- 4 months ago
Leave it to Technical Editor Kevin Cameron to start in 1862 with the first guy who conceived the four-stroke combustion cycle. KC proceeds with Editor-in-Chief Mark Hoyer on the journey to the combustion chamber we have today and why it's shaped how it is, flatheads to hemis, two valve, four valves and more valves! There's so much to cover in such a small space. Join us!
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SportsTranscript
00:00:00we're here once again with the cycle world podcast i'm mark hoyer i'm the editor-in-chief
00:00:04and with kevin cameron our technical editor today's topic inside the hot room
00:00:11this is everything about the combustion chamber our uh our striving to get a homogeneous charge of
00:00:19gasoline and air most specifically oxygen yes that's the part we care about that stupid nitrogen
00:00:28get rid of it um it's there to keep the lid on that's good if we breathe pure oxygen bad things
00:00:36happen yeah not not good um but yeah every everything that's happening with a combustion
00:00:42engine of course we need good combustion we want a homogeneous charge we want everything to be
00:00:47perfectly mixed mixed and within some confines what we're looking for is perfectly complete
00:00:53combustion because we'd end up with what water and carbon dioxide yeah that's when it's complete
00:01:01if it's perfectly complete that's what we want yes that would be great if we could do that we're
00:01:07striving for that um we'll talk about you know ways that we reduce hydrocarbons and other things about
00:01:14the combustion chamber because the combustion chamber would you say the combustion chamber
00:01:18extends from the top of the top ring yeah the lid of the chamber clear around to the other side yeah
00:01:25this stuff we're gonna talk about that um so thoroughly complete combustion and within the confines of
00:01:33the crank rotation combustion is short as we can practically make it yeah because the longer hot gas
00:01:43sits against cool comparatively cool metal the more of the energy in that hot gas will be lost
00:01:51as heat to the cooling system right whether that be fins or or water yeah that's a great point we want
00:01:59to keep the heat in the chamber and not have it transfer out through the engine and this reminds me of a
00:02:04story uh of early drag engines the iron drag engines were faster than the ones with the aluminum heads
00:02:13yeah because iron wasn't transferring heat out of the chamber as quickly so in that short duration
00:02:20where you didn't have to like on an air cool racing motorcycle where you had to make a great big heavy
00:02:25cylinder head to be the repository for all the heat that you were getting on the front straight and
00:02:30then roll off let it cool get rid of some of that in a drag car you're just like it's cold
00:02:36and you're done so it's the iron ones were for a period of time until the advantages of aluminum uh could be um
00:02:44exploited or faster so you want to keep the heat in the chamber if you could keep all the heat in the chamber
00:02:50man is that 100 efficiency close well it's yeah because there's all sorts of things in nature that are
00:02:57constantly nibbling away at perfection and um we wear pointed shoes when we walk around in the combustion
00:03:06chamber to to deal with those little critters well in 1862 while the u.s civil war raged and brother
00:03:17i love how it goes back to 1862 a frenchman named beau de rochard um came up with the four stroke
00:03:29concept and he got so many things right he said that the combustion chamber must have the smallest
00:03:39possible surface area which we were just talking about um we we want to lose this little heat from
00:03:46combustion as possible so he says this in 1862 and how come we blow it so hard over and over again
00:03:53like how do we screw that because when we when we get in the internal combustion engine is already there
00:04:00and there's already a stack of little cards with handle with sticks glued to them with all the right
00:04:06answers on them so they hold them up and we memorize them here's another and only by going back to first
00:04:14principles do you say oh wait a minute i get it now uh so beau de rochard was he's not given credit for
00:04:27inventing the four stroke cycle because otto and and uh langen really made it work uh in the late 1870s but
00:04:36the greatest possible peak pressure from combustion that was another beau de rochard's ideas and once
00:04:46you've created you've heated the gas above the piston you must expand it as far as it can still give
00:04:54uh meaningful work to the crankshaft well terrible fuels fixed it so that the early model t fords had a
00:05:03three to one compression ratio so it had this huge combustion chamber lots of surface area but
00:05:12gasoline was cheap in 1915 so it all worked out along came otto and langen in 1878 with the four stroke
00:05:24concept and interestingly enough the idea of overhead valves was a russian invention baris lutski in uh
00:05:391888 came up with a combustion chamber that was a cone had an intake valve at the top and a exhaust valve at
00:05:50the top and an intake valve at the side but very quickly all those ferociously creative inventors
00:06:02in france where the seed first took hold and grew fast internal combustion mania uh every conceivable
00:06:14combustion chamber chamber shape was created this was especially easy because the combustion chambers
00:06:21as i've said were large because the compression ratio was low in modern engines if you want a 13 to 1
00:06:30compression ratio you can't have a lot of valve overlap that is the valves intake and exhaust both being
00:06:38somewhat open at top dead center because you've got to cut clearance for those valves at that lift
00:06:46into the piston yes plus a safety margin
00:06:52we don't run anything down to zero no and so i mean he's the safety margin he's talking about is how
00:06:59close is the squish area of the piston which is this band on the edge to the head how does it how
00:07:05close does it come to the head because you're and how close do the valves come to the piston yeah but
00:07:10this is all dynamic right there's a little bit of it might be steel but oh it's expanding and contracting
00:07:17expanding and traction with heat and then when you're spinning everything at really high rpm that
00:07:21how many ps or yeah how many psi of pressure are we exerting on the rod and there's just a lot going
00:07:27on so we we street guys are like hey 40 thou of squish is a good place to stay and then some of the
00:07:33the fancy people will get it down to you know 28 thou or something yeah yeah really on edge so uh
00:07:43boris lutzky is one of those overlooked names uh he went to work for man in uh in germany a diesel
00:07:51company um around 1903 a whole bunch of different things happened mechanically operated intake valves up to
00:08:00that point they'd been atmospheric in our podcast about uh glenn curtis we talked about his early
00:08:07engines having intake valves that were pushed open by atmospheric pressure the piston creates a partial
00:08:14vacuum in the chamber the intake valve with a weak spring on it uh uh air rushes in
00:08:22and so 1903 was also uh the year in which the side valve engine became prominent lots of them were
00:08:35built thereafter a side valve engine has the intake and exhaust valves stems pointing downward next to the
00:08:42piston not above it as in overhead block yeah in the block next to the piston and it's nice because you just
00:08:49have a you have the tap it and the valve in the spring and it's all this kind of like relatively
00:08:55compact little guy yeah and it just sits right there on the camshaft and hard to float those lightweight
00:09:00parts and then the air goes in but it has to go like this into the chamber and then into the piston down
00:09:07down to follow the piston sure yeah well lutzky pointed out that having the valves in the head
00:09:13meant that the airflow was nearly straight in through the intake follow following directly the piston
00:09:21on it once again i looked at a 19
00:09:28a 37
00:09:32uh rolls-royce small horsepower inline six cylinder yeah the small horsepower the large horsepower cars
00:09:39were the v12s phantoms and all that and then these were the this is called the 2025 which was like the
00:09:43horsepower rating for taxes in england and uh it was an inline six it had a carburetor an updraft carburetor
00:09:54on one side of the block and it pulled the air up and went through the block and then into the intake
00:10:00manifold and into the engine i mean that's a lot get lost that's a that's a long trip and it
00:10:08i don't know what it rev to but and you had you know spark control and and mixture control
00:10:13on the string that's all i wanted it for was to yeah to be income i wanted to get rid of those stupid
00:10:19rider aids well yeah the side valve was very popular because it was simple if you want to make an overhead
00:10:28valve how are you going to lubricate the the rocker arms and the valves um the push rod ends and to be
00:10:36fair as you yeah and you pointed out compression wasn't a big deal so having a long chamber like
00:10:40that was like who cares you know yes the the side valve chamber extended out over the valves that were
00:10:47next to the piston yeah so we're in a nice little round zone but you know if the valves aren't on top
00:10:52of this circle and they're over here that means the combustion chamber extends out yeah more shaped like
00:10:58a wide shoe yeah so uh fuel really didn't get understood very well until the mid 1920s
00:11:13uh but the concept of squish is usually attributed to harry ricardo who patented in around 1920 in england
00:11:26he licensed the patent to harley davidson uh ricardo heads two things with that very good marketing my
00:11:34friend way to take the idea and do something to put your name on it and also cha-ching
00:11:41made a buck the idea of squish is and you can see how this would be easy to implement in a flathead in a
00:11:48side valve engine the piston comes up and you've located some part of the cylinder head quite close
00:11:56to the top of the piston at tdc so as the piston arrives at tdc the air between it and the squish
00:12:05zone on the cylinder head goes it is squished out into the chamber above the valves where it creates
00:12:13turbulent motion this is what makes combustion move fast that's why we have this piston and the spark
00:12:22plug is in the middle of the valves and so this ring all the way around the edge squishes it all and
00:12:28concentrates it also mixing it up giving it lots of turbulence yeah and then it gets lit right in the
00:12:35middle and it's nice and compact in this area and bang and away we go and this is this is a out of a
00:12:40probably 12 to 1 engine and uh r1300 gsa is uh 13 to 1 i believe or more even the r12 g slash s and
00:12:54you know air oil cooled flat twin they have pushed that i believe to 12 or 13 to 1 yeah through other
00:13:03you know there's lots of hocus pox going on but yeah so that's the squish and that's what we want
00:13:07mixing mixing mixing and then concentration around now this concept of squish was invented at least four
00:13:15times um pique pique pique a mokan company in geneva is one inventor they didn't bother to patent it
00:13:27it worked for them another inventor was walter moore who later designed norton's cs1 camshaft one
00:13:35their first overhead cam engine which later became the celebrated manx norton road racer
00:13:44venerated too venerated yes indeed and uh charles franklin the irishman who became a
00:13:57self-made racing success at the great brooklyn speedway in england and was then made chief
00:14:03engineer of indian in the usa he invented squish sort of by accident uh walter moore too they had a new
00:14:13four horsepower douglas and they took it to the test hill at brooklyn speedway and it would not go up
00:14:20the hill it just started knocking immediately and quit running so
00:14:26so walter moore wasn't going to take any nonsense from reality so he took a brand new casting the
00:14:36cylinder head and the cylinder were cast in one piece sawed it in half and looked at the geometry
00:14:44and he went to the foundry department he said boys i'm sending out in those days it wasn't for pizza
00:14:50uh for dinner and we're going to be here all night and they made a number of different changes to this
00:15:00shape and he came up with a shape that seemed to run particularly well and today we would call it
00:15:07squish i wonder what they all called it you know i wonder if they had a name for it because typically
00:15:12what happens in academic circles is like you i don't know in the areas of philosophy
00:15:18they they make an entire career on just changing what they changing the language you get it it's
00:15:24kind of the same thing we're talking about the same topic but somebody comes up with like michael
00:15:29foucault had this like uh no was it derrida had this concept of deference and it was like the difference
00:15:37between it was i mean i love philosophy because it's just this is so academic endless noodling
00:15:45it has no consequence let's how are we going to choose the main jet probably not derrida yeah exactly
00:15:56it's a weird relief anyway the reason i go on about this uh multiple invention of squish is that
00:16:04at the beginning of any new technology there are a lot of people worked on it they haven't decided
00:16:09the best way to do it yet and everyone's hoping to hit the hit right and so at least four inventors
00:16:18of squish and during the 1920s and 30s
00:16:23side valve engines were noted for their good pulling power from low speed why was that because squish
00:16:32gave a vigorous stir to the fuel air mixture so that when it was ignited it burned rapidly too fast
00:16:41for the chemical process that lead to knock to take place meanwhile the overhead valve engines such as
00:16:49the eight valve indian board track racer and harley's eight valve they were good on top end but if you
00:16:56pulled the engine down to low speed oh knocka knocka knocka if only they had yeah if only they had good
00:17:03squish right so but the compression ratio was so low that the piston was never anywhere near the head
00:17:09in those early engines so people weren't thinking how can we transmove transpose squish from a side valve
00:17:17to an overhead valve and uh charles franklin's yeah we were getting turbulence without needing it to
00:17:27happen because only because of velocity yeah because there's a lot of velocity in the intake process
00:17:34especially once you realize there's an advantage in high speed intake anyway um
00:17:43charles franklin's side valve indians based on the power plus engine often won races against the
00:17:51eight valve overheads how could that possibly be squish is how so and how and how misleading that was for so
00:18:01long yeah because we didn't have the answer that took us to where we are today we didn't have dfv
00:18:10to look at oh yeah wouldn't that be great could you imagine taking a dfv
00:18:15cosworth back in time and just secretly applying that to the metallurgy that was available and
00:18:21have a look at this fella walking out of a shed and going to brooklyn's and just kicking ass
00:18:25yeah uh that's i think the basis of every time travel movie is that kind of all-knowing power
00:18:32right that gives us yes and that's the basis of vintage racing because you do know now what you
00:18:39should have known then well it's it's really true you know you go out to arma and you look at the bikes
00:18:44that are competing in in 500 premiere or whatever the you know the 500 class where you get manxes and all
00:18:51that stuff nobody's really winning on a truly vintage manx you know it's all it's all remade
00:18:58the g and they're turning 9 000 rpm yeah they're kind of scratch built and they've got electronic
00:19:03ignitions and there's just many many pieces of that new metallurgy new parts all the good stuff it's all
00:19:11due respect to a team obsolete for showing up with stuff that's actually vintage and got magnetos but
00:19:16you know and what what robert ianucci says is that so often they've been able to win races using the
00:19:25standard stuff because it was so optimized at the time it worked well anyway it's not just not as often
00:19:34yeah from well from the middle 1920s through the 30s fuel octane number its resistance to knock
00:19:43was steadily improving and in order to to live right on detonation store step they raised the
00:19:53compression ratio with each improvement in fuel quality and when you raise the compression that
00:20:00is make the combustion chamber smaller you create a higher peak pressure and you also have a higher
00:20:09expansion ratio 10 to 1 compression is also 10 to 1 expansion so what this was doing is it was moving
00:20:19the cylinder head closer to the piston sooner or later somebody's going to say now that the cylinder
00:20:28head is so close to the piston maybe we could create squish between the two and that somebody was
00:20:36connected who had to exchange bond on a lesson and looking for each ROBERT 2 until that it has been
00:20:42hybrid to this Growing Folks lot ÅŸoke lead to the?".
00:20:50His journey on their journey, reading not the same rykshireFT, you know, that was Leo Kuzmicki who escaped from Poland during World War II on a magnificent
00:20:55And Norton's race director got to talking.
00:21:04And the result of this was maybe this idea of bringing parts of the piston close to the head could work in an overhead valve engine.
00:21:18And this is strange because Joe Craig, who was in charge of racing at Norton and virtually ran the company, he sucked up their whole R&D budget, which is why they kept on making singles when other companies were, well, Triumph was raking it in with the parallel twin.
00:21:40Norton's were sort of stuck in the mud until 1947.
00:21:43But when at Norton, they decided to build a squish piston, they solved two problems.
00:21:53Well, I won't say solved.
00:21:55They ameliorated two problems.
00:21:57First of all, to get high compression 10.5, say.
00:22:01Should we call it research and amelioration?
00:22:05Yes.
00:22:06Instead of R&D.
00:22:07I've often wished to be ameliorated.
00:22:10In any case, here's this piston dome and it's sticking up there, but you can't create squish in the center of the head.
00:22:18You can only do it around the edges.
00:22:20So we get to take that material, lower it in the middle and raise it up to the points where there aren't valves to where it can nearly touch the cylinder head.
00:22:34What this did at first was it removed the obstruction of the piston dome to a considerable extent so that the rapid motion of the intake entering the cylinder head created a tempest in a teacup.
00:22:50Lots of turbulence.
00:22:51Lots of turbulence.
00:22:53As the piston rises, when you've got that terrible piston dome on there, the turbulence is sort of, I quit.
00:23:03Nice one.
00:23:04That's a better one than the steeple, church steeple type.
00:23:09Yeah.
00:23:09So when they made the squish piston, they picked up horsepower and torque.
00:23:18Oh, thank goodness.
00:23:19And it's been squish ever since.
00:23:25Now, the combustion chamber, as I said earlier, originally it had, there was such a variety.
00:23:33There were engines that had three exhausts on one side with their stems pointing down, three more exhausts on the other side, and a huge intake valve in the head.
00:23:45Any concept you can think of, any concept you can think of, they tried it.
00:23:50And to extend the combustion chamber out over these side-located valves meant that there could be crevices, nooks and crannies, as a certain brand of English muffin calls it,
00:24:07in which flame could persist after the combustion process so that when the next fresh charge was compressed, it would go off prematurely or otherwise at the wrong time.
00:24:24And this, at the time, was called misfiring, meaning firing when we don't want it to, firing badly.
00:24:34I was talking to an engineer, and they were talking about the combustion chamber shape, et cetera, and ignition or injection timing and which way the injector was pointed.
00:24:48Because if you, you know, your instinct is, let's fire it into the cylinder directly with the charge.
00:24:54But in fact, that can keep it from mixing.
00:24:57But it's also one reason the showerhead injectors were extremely long distances so that at high RPM it had time to atomize, and they were just sitting in the airbox.
00:25:07But you could point the injector sideways to the flow and get it to tumble.
00:25:10But he said the goal was reduced cycle-to-cycle variation.
00:25:15And I thought, well, that's it.
00:25:16Oh, cycle-to-cycle variation.
00:25:18That's a nice way to, that's a nice academic way to put, yeah, she's running good.
00:25:24The thing is, with cyclic variation, if you could take the very best cycle that you've recorded on your combustion chamber microphone system
00:25:37and make the engine run like that all the time, you might gain 20%.
00:25:43And it might even be with improved fuel consumption.
00:25:51I need that on my 460.
00:25:55Bobby Strauman, who was the champion man for so many years at the races.
00:25:59I've seen all the pictures with his little monocle, the little magnifier.
00:26:03Yes, peering at your spark plug.
00:26:04Well, I think you could go up with the ignition advance a quarter of a degree.
00:26:11You can see a quarter of a degree on the spark plug?
00:26:14I wish we could get inside of here.
00:26:16This would be a hard one to read, but probably okay.
00:26:19Long little electrode, positive.
00:26:23You know, I'd say most of us who are still looking at this, because nobody looks at these anymore.
00:26:28All you're doing is looking at your lambda and all that.
00:26:31They're unseen.
00:26:32You don't have to use this anymore.
00:26:35We have oxygen sensors.
00:26:37Yep, oxygen sensors, others, you know, pressure, temperature.
00:26:41Yeah, we're going for it.
00:26:43But, you know, it's, oh, cocoa brown.
00:26:46You know, he's like, oh, light brown, cocoa brown.
00:26:48And that's where a lot of people's spark plug reading, you know, begins and ends.
00:26:52But it's actually all those little rings that are down here on the center electrode and how's it coming out on the negative.
00:26:59This is sort of a bad example because it's a twin.
00:27:02But this is like tricks to make the linotype work faster.
00:27:06We don't use linotype machines anymore.
00:27:10Well, we do in ARMA.
00:27:12Yeah, sure.
00:27:14Well, the two valve, four valve thing in the 1920s, the four valve engines of World War I aircraft engines were complicated.
00:27:28They weren't necessarily unreliable.
00:27:32But the more parts you have, the more failures you can potentially experience.
00:27:39And at Fiat, they came up with the idea of putting two valves above the piston and allowing them to be very large by angling them apart so that they were on the long diagonal rather than having to fit inside the bore circle.
00:27:54And that was the ruling paradigm in combustion chamber design from 1923 until the early 1950s.
00:28:07But even, yeah, even then, the Jaguar XK engine that they used in, you know, the XK 120, 140, 150, E-types, and pretty much everything that they made until they made the V12, that engine persisted.
00:28:20The XK engine persisted until 87, 88, 89, 90, somewhere in that range when they came out with the double overhead camber and they were still using that.
00:28:33And it's the chamber that you described.
00:28:34This is a piston from a Jaguar, hemispherical head, and the cams are out.
00:28:39I forget the included angle of the valves, but the cams are tuned way out.
00:28:44Yep.
00:28:44And, yeah, they made it work, although they do detonate at 1,800.
00:28:48That's a very susceptible RPM.
00:28:51A bad time.
00:28:53Yeah, you got it.
00:28:54Yeah.
00:28:55So 90 to 96 degrees included angle.
00:29:01Well, this was fine when compression ratio was low because you could have that big hemispherical combustion chamber.
00:29:09That and the flat top piston worked out just fine.
00:29:12Five to one compression.
00:29:15We're good.
00:29:16But when the fuel octane began to improve as the chemists and the engine people began to cooperate
00:29:23and understand each other's problems, they began to push detonation away.
00:29:33All hail leaded 110, folks.
00:29:35You got it.
00:29:38So this two-valve thing, when the fuel octane got better and the compression ratio rose from five to over 10 by 1939,
00:29:50then you had this tremendous piston dome sticking up into the combustion chamber,
00:29:57both of which had a large surface area violating Beau de Rochard's first principle,
00:30:05smallest possible surface area in the combustion chamber.
00:30:09And it wasn't that Keith Duckworth was thinking of Beau de Rochard.
00:30:20He was simply dealing with the problems that were in front of him.
00:30:28Frank Cosson.
00:30:29Yes.
00:30:30Keith Duckworth.
00:30:31The chassis man.
00:30:32Frank Cosson, Keith Duckworth, Cosworth.
00:30:35Joined to make Cosworth, yes.
00:30:37And Cosworth, you know, as we've said many times, I just want to put the stamp on it that, you know,
00:30:42Cosworth really did it.
00:30:43Cosworth built the combustion chamber four-valve head.
00:30:47That everything has nowadays.
00:30:49We're all.
00:30:50There's a little step along the way in the middle of 1960s when Honda re-adopted four-valves per cylinder,
00:30:57not because it flowed so well, but because those little tiny valves were so much easier to control at very high RPM,
00:31:06up to and including 21,500 for the 1965 RC-115 50cc twin.
00:31:19And so four valves came back into automotive use and then into motorcycle use,
00:31:26but still with the large valve-included angle.
00:31:29And Duckworth moved forward by increments in his thinking.
00:31:37And what he ended up with was a bore that was about 1.3 times the stroke,
00:31:44so a fairly large bore with four valves with their stems at a 32-degree included angle.
00:31:54So the chamber is now like a shaving off of a hockey puck.
00:32:02And instead of having a squish to generate all of the turbulence,
00:32:10he decided to compromise on the uses of the intake flow.
00:32:17If they tipped the intake port up so that it aimed down at the piston, cylinder filling was best.
00:32:27If they had it at a lower angle, it flowed across, hit the other cylinder wall, and formed a barrel motion.
00:32:37That's what Duckworth called it at first.
00:32:40Today we call it tumble.
00:32:42Tumble.
00:32:42And it's a way of storing intake energy in the cylinder so that as the piston rises,
00:32:49it's like the skater who draws his or her arms to the chest and spins faster and faster.
00:32:59So what happened when the Cosworth V8 of 1967 went up against the French engine,
00:33:10which had much more valve area.
00:33:14And in those days, if you read the books that we've all read, if we're mad enthusiasts,
00:33:23the Matra V12.
00:33:26Legendary sound.
00:33:27Yes.
00:33:28Well, we love 12 cylinders.
00:33:30No question about that.
00:33:34The little V8 just left that V12 behind.
00:33:38What was going on?
00:33:41The V12 had a slower burning combustion chamber.
00:33:44It had a lot of combustion chamber surface area.
00:33:49Beau de Rochard, are you listening?
00:33:52And so heat that should have been driving the rear wheels of those Matra racing cars was driving the radiator.
00:34:02And in the Cosworth V8 DFV, that heat was indeed driving the rear wheels.
00:34:12And it took a couple of years for the competitors to kind of, what are these guys doing?
00:34:18How are they getting these unreal results?
00:34:21And that four-valve, flat, turbulent combustion chamber using tumble is the world standard now for combustion chambers for cars, light trucks, motorcycles.
00:34:38Because it works, it's best for racing, and it's best for grocery getting.
00:34:47Because it puts everything in a reasonable place.
00:34:51It burns quickly, so it doesn't waste fuel.
00:34:55And it's just an all-around winter.
00:35:03And that pretty much concludes the combustion chamber story, except for the fact that now, with the aid of electronics, we no longer are relying on ignition that comes at a fixed point.
00:35:21For example, if you have an old parallel twin triumph, say a 65 Bonneville.
00:35:26Well, I know people are thirsty by now, so what I want to say is Velocet.
00:35:31Okay.
00:35:32And I'll use the Velocet BTH Magneto as an example.
00:35:36You were going to...
00:35:38I was going to say...
00:35:39I'm hopefully saying what you're going to say.
00:35:41Yeah.
00:35:42Yep.
00:35:42Is that mine has an automatic timing device, but it's sort of the same if you're doing the manual timing device.
00:35:48Which, in the old days, on a Magneto, you would move the lever and change your timing.
00:35:54So when you set your timing, you'd set it at max advance, because that's what was important.
00:35:57And you'd set it at 36 or 40 or whatever the book was asking for.
00:36:01And then when you went to start it so that it didn't backfire and throw your leg through your chin, you would turn it to the starting...
00:36:08Retard.
00:36:09Retard.
00:36:09You retard it.
00:36:10And it's 10 degrees before top dead center or 5 degrees instead of 40.
00:36:16Yep.
00:36:17And it did...
00:36:18So anyway, because you can't kick it hard enough to get past compression and do all of that with enough momentum to get it to go over and start.
00:36:27Because it's happening too soon.
00:36:29And that's why it kicks back and goes kapang and then ow.
00:36:32But if you take it back to 5 degrees, you can...
00:36:35And you have time and then dip, dip, dip, dip.
00:36:37And then you can mess with the timing a little bit and get the nice idle that you're looking for.
00:36:41But as soon as you roll away, you're turning the timing to advanced.
00:36:46You're giving it max timing.
00:36:48The ignition on the Velocet, another drink, is an automatic timing device.
00:36:56And it has springs and weights.
00:36:58And pretty much, it's not much of a curve.
00:37:01It comes all in at a certain RPM.
00:37:03It happens fairly quickly.
00:37:05Like 1200, yeah.
00:37:06Yeah.
00:37:06Even with fresh springs, even the 1995 Ducati 900 SS with Kokusan ignition modules, all they did, just like a 1975 Leverta with an early Bosch electronic system, it's practically a switch.
00:37:22It has an idle RPM.
00:37:25And on the Kokusan, I want to say it's like 2700, 2200.
00:37:30It goes from 10.
00:37:32I can't remember.
00:37:33Sorry if this is wrong, Ducatisti.
00:37:35But it's 10 and then say it's 36.
00:37:38It doesn't go, ah, it goes, I mean, in an RPM range, it's like 100.
00:37:45It's a step function.
00:37:47It goes from 10 to 36.
00:37:48That's why when you're on choke with a standard ignition on a 95 Ducati, it's like, and you're like, no, no, no, less, less choke.
00:37:56And it stalls because it doesn't have timing to run where you want it to.
00:38:01And I spent, I don't know how many hours on the dyno with my Leverta, 75 Leverta triple, thousand.
00:38:08I had bought a new pipe for it because the stock clock Franconi had a collector that was the size of a pencil.
00:38:14Yes.
00:38:15This is a thousand and it's making, and it was quiet.
00:38:17You know, they were, they were trying to quiet them down.
00:38:19You know, it was making like 54 horsepower or something like that, which is about what a commando would make, a good running commando.
00:38:27And I'm like, dang, this is, this doesn't seem right.
00:38:29So I got the key and exhaust system, which was a stainless system made in England.
00:38:33Cost a fortune.
00:38:34But I put that thing on and I started rejetting the carburetors and I was going up and down the street to Ron Wood, you know, uh, on the needle exchange because Ron Wood racing, racing was doing all the Dell Ordos for the flat track guys.
00:38:46And people were using them, uh, at that time.
00:38:49And that's what, that's what the Leverta had.
00:38:51And I was on the needle exchange program and, uh, I am detail oriented and I have a, an ability to concentrate on things.
00:38:59A lot of people find very tedious, but you think about it a lot.
00:39:03It's just a trait, you know, it's a trait.
00:39:05And it comes, comes about sometimes when I'm cooking and even I focus too much and I'm not having enough fun.
00:39:10Uh, but, uh, I got the jetting, what I thought was really good, but I couldn't get rid of the stumble.
00:39:17There was the stumble and I would hold, and the dyno is nice because you, you can just stand next to the motorcycle and do things with the throttle and listen to it.
00:39:25You're not, no helmet, none of the, no traffic.
00:39:27And so you're just running down on our dyno jet two 50.
00:39:30It's right there in the other room.
00:39:31And you're just running it and I couldn't get rid of the stumble and I forget the RPM, but it was around 3000.
00:39:38And I mean, this was, I had done it, man, that they were synchronized like crazy.
00:39:42I put a straight edge across the top of the carburetors cause they were metal mounted and you could kind of rotate them and it was all on cables.
00:39:49Yeah.
00:39:49So what they're not racked, that meant that, you know, let's make them perfectly straight.
00:39:53So I got my machinist edge, you know, and put that on there and I did all of that work.
00:39:57And I got exactly the right needle and I got the right slides with the right cutaway and the right damn, uh, accelerator pump ramp.
00:40:05Cause there's a ramp on them that kicks the accelerator pump.
00:40:08So there's a lot going on and I worked it and it was running great.
00:40:11And I'm like, I could not get rid of the stumble.
00:40:13I tried, okay, we'll go to smaller pilots and, you know, and I burned a lot of brain cells and I just, you know, I had to hit the reset button and I did reading and I read and I read and I read and I finally found an instance where the Bosch electronic ignition was explained.
00:40:32And it said it, it holds 10 degrees or whatever, you know, I'm guessing it holds 10 degrees until 3000 when it switches to 35.
00:40:42And I was on the dyno going, and I'm getting like a little, I'm like, what is that?
00:40:49So today, yeah, today's ignition boxes have optimized timing, uh, minimum for best torque MBT.
00:41:01That has been, uh, determined on the dyno with standard units.
00:41:07And that is stored as an ignition map, uh, in the ECU and the engine does not breathe equally well across the whole power band.
00:41:19If the cylinder is quite well filled, the flame is going to spread more rapidly.
00:41:25The flame speed will be higher in areas where negative wave arrives.
00:41:30Just as the intake valve is closing and sucked out some of what should be in there, it's going to need more ignition.
00:41:37So what modern ignitions do is they provide the timing that is best for that speed and that throttle opening.
00:41:45And that is all canned in the ECU.
00:41:48And by the way, check company, Ignitech makes a programmable ignition box that you can plug into your Ducati system.
00:41:59And then you can put a true curve in it.
00:42:01And you know what I, I mean, I got a lot of benefits out of that.
00:42:04A lot of low end smoothness because now the, the timing is happening at a place that's optimal.
00:42:09Like what are you, what are you looking for at idle for say when you're tuning, you're looking, the reason you change the mixture on a carbureted bike and even on a fuel injected bike is the RPM.
00:42:22You tune it, you tune a carburetor idle mixture screw to get the highest RPM.
00:42:30What is the highest RPM?
00:42:31It's the most horsepower.
00:42:32It's the maximum power mixture that you're looking for.
00:42:37You're looking for the maximum power mixture.
00:42:39That's what you're doing.
00:42:40The ideal spark timing could be 10, could be 14, you know, you move it around and you're going to naturally, well, not naturally, but anyway, you're looking for the maximum horsepower.
00:42:50And then now you can look for that everywhere across the, and the Ducati completely changed that low speed tractability from the Cocusan to the Ignitech.
00:43:00Low speed tractability, ability to set the choke at 1800 without it either running away or stalling.
00:43:07It became a much different motorcycle.
00:43:10I never changed one in the Laverda and Velocet.
00:43:15It's still mechanical advanced, but you can put a BTH replacement electronic ignition on those.
00:43:22Hide your battery.
00:43:23And if you don't want to, people talk about the unreliable magneto and they're going to replace it with the electronic ignition.
00:43:29And I say, you realize that magneto is 50 to 80 years old or more, a hundred.
00:43:36Yeah.
00:43:37Could be a hundred.
00:43:38Well, here's the last problem for combustion chambers.
00:43:42And that is, uh, we want, uh, we want to be able to have good performance on top end, but we want to have very high compression for acceleration.
00:43:53Now, acceleration just means performance below top end with the engine accelerating.
00:44:00And compression ratio, the highest possible, highest usable compression ratio, HUCR, uh, is what we'll use if we have electronic means to prevent disaster.
00:44:15And this is why modern engines such as 1300 GS from BMW have knock sensors.
00:44:24If the engine begins to knock, it retards the spark a little bit and then tries again.
00:44:30Oh, he's got a bad tank full of gas.
00:44:33Well, we'll have to sort of hover down here.
00:44:35But once you're protected against detonation, you can go way up with compression ratio without disaster.
00:44:45And that's what manufacturers have done.
00:44:5013.3, 13.5 to one.
00:44:53Those numbers were just, uh, madness 20 years ago.
00:44:59I haven't looked recently, but I have searched in the past for essentially an aftermarket knock sensor that I could, like, I could hook up to an ECU and control spark on vintage engines just so that.
00:45:13Well, you, um, wear a stethoscope and, uh, keep your thumb near the spark lever.
00:45:20Push the screwdriver on there and stick your ear on it.
00:45:23That's the one.
00:45:24Works good.
00:45:24Long screwdriver, folks.
00:45:25So now we've raised the compression ratio.
00:45:29So the piston is very close to the head.
00:45:33What does this do?
00:45:35It kills charge motion.
00:45:37It kills turbulence.
00:45:39It slows down combustion.
00:45:42Well, we go in there and we round any sharp edges like the edges of the valve clearance cutaways.
00:45:50We smooth them out.
00:45:51We do everything we can to prevent energy loss from this mixture that's turbulating around inside there.
00:46:03But we find that it really isn't good enough.
00:46:06So at some point, for example, if you're racing, if you're going to a track that features a lot of acceleration, you run the high compression.
00:46:17Knowing that, yes, you'll lose on top end because the turbulence won't be there to support the fast combustion.
00:46:29It's a worthwhile sacrifice because you'll win on the acceleration much more than you lose on top end.
00:46:36And there have been engines that were very much this either or way.
00:46:42But to create an engine that can do it all is quite an achievement.
00:46:47And this is one of the areas in which it almost seems as if Euro 5 is cooperating with engine designers because Euro 5 says, well, we want to cut down on unburned hydrocarbon.
00:47:04And so we don't want the intake and the exhaust valves open simultaneously more than just a little bit.
00:47:12Well, you're thinking to yourself, that means we can make the valve clearance cutouts in the piston crown shallower.
00:47:21That will help to raise compression.
00:47:25So now we can move the piston away from the head a little bit for the same compression.
00:47:32Another thing that happens, of course, I talked to Claudio Domenicali, who's now the CEO of Ducati, about this years ago.
00:47:40He said, often we have to go to excessive ignition lead to burn very large bore engines with short strokes because that combustion chamber is so slow burning.
00:47:56So that compromise remains.
00:47:59There is no way to have it all.
00:48:01But you can slant the compromise in whatever direction you need to go.
00:48:07So another sideline is that the United States Army used a lot of diesel engines.
00:48:20And naturally, those diesel engines require a long supply train back to a ship somewhere tied up at a pier.
00:48:29They're loading barrels of fuel onto trucks, and the trucks are grinding their way through Pakistan and into Afghanistan, just to give an example.
00:48:40So it would be a good idea if the engines used less fuel.
00:48:45What if we made an engine whose combustion chambers stayed at a very high temperature the whole time?
00:48:53Heat loss is proportional to the temperature difference between the hot thing and the cold thing.
00:49:01This is called delta T, delta meaning a small change in.
00:49:07Delta T rules.
00:49:10The Army put a lot of research into designing what they called an adiabatic engine, one which neither gains nor loses heat through the vessel.
00:49:20And they found they couldn't do it.
00:49:27They found that the turbocharger energy, which comes from the exhaust and creates some back pressure, required to push hot air, to push any air into such a hot combustion chamber, the air immediately heated and said,
00:49:47I'm not going in there, I'm not going in there, I'm not going in there, no way.
00:49:50And so it expanded.
00:49:52Yeah.
00:49:53And you're trying to compress air whose temperature is rising.
00:49:58A fool's game.
00:50:01And so they gave up on the adiabatic engine.
00:50:06But subtle people in the engine business, like Rob Muzzy, for example, or the people at Ducati, Gigi Mengele, are thinking about these basics that go back to Bo de Rocha.
00:50:25And they are trying A, trying B, trying C, so that combustion chamber design continues to evolve.
00:50:36Now, you'll notice that automobile engines are going back to bore and stroke approximately equal, or even that strokes are now in some engines longer than the bore.
00:50:49That's a many-sided sort of change.
00:50:54On the one hand, you're making the combustion chamber smaller, reduces heat loss.
00:50:59That's good for economy.
00:51:01It's good for carbon reduction.
00:51:04You don't use as much fuel.
00:51:05You don't spew out as much carbon dioxide.
00:51:08And also, of course, the piston ring crevice in a big bore.
00:51:13It's a long way around a four-inch piston, but a three-inch piston, it's only three-quarters as far.
00:51:20So, yeah, let's pause there.
00:51:21That's where unburned hydrocarbons are coming from.
00:51:24So what he's talking about is, here's the piston.
00:51:26And you can see the top ring is here, and the crevice is this amount of piston to the top of this ring.
00:51:33So there's air fuel mixture coming here, because as soon as it lights, the pressure goes up.
00:51:38And these piston rings are designed to be essentially inflated by the pressure.
00:51:43And so the pressure goes in behind the ring and blows the ring out against the cylinder, and then you have that crevice.
00:51:52If you look at the top land on this, it's a little bit farther.
00:51:57The rings are thicker.
00:51:58These have a higher friction ring.
00:52:00But that distance is farther, and that would hold more hydrocarbons.
00:52:03And then if you make the bore this big, 6th and an 8th, versus this, which is probably 85 or something, 82.
00:52:16Yeah, you know, this is a lot more crevice, right?
00:52:21Look at the distance there.
00:52:22So, B25.
00:52:24B25.
00:52:25Lots of rocks.
00:52:26Lots of friction.
00:52:27Sorry, Spotify.
00:52:32I just showed you some pistons.
00:52:35We used props.
00:52:37Occasionally, we used pictures.
00:52:40Also, one of the things that came to mind is that we've talked about tumble.
00:52:44We talked about barrel motion in the DFV.
00:52:47But we skipped how two valves were doing that kind of thing.
00:52:51Ah, yes, so we did.
00:52:52And the funny thing is, the English went with it, and the Italians, with the exception of Dr. Taglioni, ignored it.
00:53:02So, here we have the bore, and here's the intake port and the intake valve.
00:53:08If that's what we have, the air goes in symmetrically.
00:53:13You get no rotation of the air one way or the other.
00:53:16So, basically, what he's saying is the port comes in perpendicular to the cylinder.
00:53:20Right, but if we move the port off to one side, it's like the game we play, filling a bucket with a hose.
00:53:31You can make the water swirl to the right.
00:53:34You can make it swirl to the left.
00:53:35You can make it stop by using the velocity of the water coming from the hose to make the water, in our case, the fuel air charge, spin.
00:53:50That is a way to store intake energy above the piston that may make it to the ignition point so that it will, that turbulence will accelerate the flame speed because it shreds the flame kernel created in the spark plug
00:54:08and carries the shreds quickly to all parts of the chamber, causing a rapid pressure rise.
00:54:17Exponential flame propagation, man.
00:54:19Yeah.
00:54:20Everybody's shaking hands, as you said.
00:54:21More people doing it, faster the disease spreads.
00:54:25So, this is the piston, but we'll call it the chamber.
00:54:28And here's my pencil pointing to the center.
00:54:30If that's the intake, then the air is going this way.
00:54:33It's hitting this big knob in the middle, not doing its thing.
00:54:36But if you just go kick it to the side, here's the hose at the side of the bucket, and it's whipping around and tumbling and doing its thing.
00:54:45Yep.
00:54:46Yeah, those offset ports, you find them all over.
00:54:49You certainly do.
00:54:50It's great.
00:54:51And so, you don't need, well, here's, here's, I would like to bring up the Norton Commando because it's a great example of a two valve that's doing a lot of things right.
00:55:04So, overhead, overhead cam, four valves for cylinders, definitely where we are.
00:55:09It's definitely superior.
00:55:11But this parallel twin designed, what, in 40, 38, 9?
00:55:18You know, the essential beginnings of the Norton twin.
00:55:221947.
00:55:2347.
00:55:24Yeah.
00:55:27It ran great.
00:55:28And the ignition timing, the max timing on a Norton Commando is 28 degrees.
00:55:33Quick.
00:55:34Very quick.
00:55:35I know you're thirsty.
00:55:36Velocet, you take a Velocet, very typical hemispherical combustion chamber.
00:55:40Your two valve spec is somewhere in the 38 degree range.
00:55:45Can't do that with our, the fuel we have, like the 91 that we have here.
00:55:49You just can't do that.
00:55:49So, I love a leaded 110.
00:55:50You put that in.
00:55:51You can do whatever you want with the timing.
00:55:53Yes, sir.
00:55:54Optimal good times.
00:55:57But, yeah.
00:55:57So, it's, you can't.
00:55:59That is why, in classical times, when Grand Prix racing teams had no idea what fuel would
00:56:09be the official fuel in Spain, in Italy, wherever they were running the next GP, teams that were
00:56:19wise carried a drum of toluene, which has a good anti-octane number, and they would just add 10%, 20% to the official brew.
00:56:34And moderately less bad for you than tetraethyl lead.
00:56:38So, that's good.
00:56:40Yeah.
00:56:40Great solvent.
00:56:41It's usually a lot, a big, a big part of your, you know, carb cleaners and stuff.
00:56:46It's a great solvent.
00:56:48So, you.
00:56:48And it's not available during wartime because they need the toluene to make tri-nitro toluene, which is TNT.
00:56:57A high explosive.
00:56:58So, these engine things that we've been working on, they're not at the end point yet.
00:57:09New ideas keep coming along.
00:57:12And just the other day, I saw that somebody is making a rotating sleeve diesel engine.
00:57:20Yes.
00:57:21Because they found that most of the piston ring friction occurs within a few millimeters of top and bottom dead center where the rings are not moving for long enough for the oil between them and the cylinder wall to squeeze out.
00:57:38So, there is not metal to metal contact maybe, but certainly metal to oil additive contact, which causes a friction coefficient that may be 10 to 100 times greater than an oil film.
00:57:55Well, you do get a lot of zinc in the diesel oils, the ZDDP.
00:57:59So, that's sort of the last line of defense, particularly on, you know.
00:58:03Yes, it is a solid lubricant that comes into action wherever there's high temperature.
00:58:11I found out that it's in.
00:58:13Oh, yeah.
00:58:13Go ahead.
00:58:14It's self-healing.
00:58:16As long as there's ZDDP, zinc, diethyl, alkyl dye, something.
00:58:24Anyway, as long as there's additive in the oil, it's self-healing.
00:58:29And so, there can be a polishing action.
00:58:34Right.
00:58:34So, it lays its little surface and then it just, it's always there.
00:58:38Scrapes it off.
00:58:39Unless, what I've found out recently, that there's a high instance of calcium and I think another mineral, some of the detergents.
00:58:46And that's the interesting thing about diesel oil is it has the ZDDP you might want for a flat tab at engine.
00:58:52Yeah.
00:58:53But it also has a very high detergent, which actually can work against the ZDDP to a little moderate.
00:59:00Because preventing it from forming the coating in the first place.
00:59:04Yeah.
00:59:04Or even removing it.
00:59:08Dispersons.
00:59:08When you think people as old as I am, their doctors are constantly talking to them about stroke and dismal topics like that.
00:59:19And it's very much like the formation of terrible stuff in the oil.
00:59:27Oil can polymerize with oxygen to form gum and horrible sticky stuff.
00:59:38Oh, well, the old oils had a wax content in them.
00:59:42Yes, that's really old, but they could wax up.
00:59:45Just like now, if you don't have an anti-wax agent in heating oil and your heating oil tank is cold if it's outdoors, you may have to pour some kerosene in there in the winter to prevent it from waxing up on the filter.
01:00:02Just build a fire under it.
01:00:04But sludge and stroke are related because it's really the formation of sludge in your bloodstream, which is capable of occluding small blood vessels that may lead to intermediate algebra.
01:00:18Why can't I think of that anymore?
01:00:21I'm trying.
01:00:22And so dispersants, as they call them, coat the outside of any particles they find so they can't clump together and they are taken out at the filter.
01:00:37When you change the filter, you are taking away the bad guys and putting them in a safe place away from your engine.
01:00:45Nice.
01:00:46So we think of, I know I think of changing the oil and filter.
01:00:50Oh, I have to do this.
01:00:52But we actually should do it cheerfully because we are triumphing over evil.
01:00:59Well, and let's talk about evil because part of that evil from the combustion chamber goes into your engine.
01:01:06And a really good combustion chamber, you would have an oil change interval of 5,000 or 10,000 miles.
01:01:13And the oil will remain nearly honey colored or whatever color it was when it went in.
01:01:18Oh, so lovely.
01:01:19And again, I know you're thirsty, Velocet.
01:01:21So I ran my Velocet with various sort of standard pistons in, you know, remanufactured, like new cylinders, new manufactured cast iron cylinders.
01:01:34I took my standard piston and my cast iron cylinder that I bought brand new, and I took them to the machine shop because I said, hey, guys, I would like to see if these are roughly, just check the clearance first, three and a half, four and a half, five and a half, somewhere in that range, something.
01:01:54And also, is the cylinder round?
01:01:56And, you know, just bore gauges.
01:01:59I've never invested in bore gauges, so I don't have that.
01:02:01And, you know, I also wanted to get the cylinder surface scratched, basically, like, let's put a nice crosshatch because it's iron.
01:02:11And I took it there, and I went to pick it up.
01:02:13And he's like, yeah, the clearance is whatever it was, four thou, it's fine.
01:02:17And I said, is the cylinder round?
01:02:21And he says, well, it's round enough for your purposes.
01:02:23So I ran that, and it ran okay.
01:02:28It ran okay, you know.
01:02:30It was a piston much like this Jaguar piston, you know.
01:02:34Ran okay.
01:02:35But, you know, as I ran it, oil would get black in 1,500, 2,000 miles.
01:02:40Pretty dark.
01:02:41It would get quite dark.
01:02:42And I didn't really understand why.
01:02:44I was just like, oh, yeah, the oil's dirty.
01:02:46I better change it.
01:02:47And I have a filter in it, in that bike.
01:02:49Well, I reverse restored that motorcycle.
01:02:53I cracked engine cases.
01:02:54I've written about it a million times.
01:02:55But I've cracked the engine cases.
01:02:58I measured the rod.
01:02:59This is the factory rod.
01:03:01Someone's pet, you know, it's polished.
01:03:02It looks like a really great rod, except that it's bent and twisted.
01:03:06And in practical terms, it was unfixable.
01:03:08I tried to do V-blocks and pins and V-blocks next to the pin on the deck.
01:03:17And then, okay, it's out of, it's not dropping into the V-blocks.
01:03:22There's an illustration of this in tuning for speed.
01:03:26And it's in a Harley book, too.
01:03:28Yeah.
01:03:28It's great.
01:03:29You just take a big bar and put it, try to bend it so it's straight.
01:03:36And it was not practical to do that.
01:03:38So I went through the entire engine, and I fixed a lot of things.
01:03:41And the crank is as perfect as, you know, a couple of different humans could work on it.
01:03:46And everything, I used a Carrillo rod that was also perfect-ish.
01:03:50And put all that stuff back together.
01:03:53And then I did a Nicosil bore, bored with a bore plate.
01:03:57And that bore plate squeezes the, what does it do?
01:04:01It simulates the compression of the material when you put the cylinder head in place.
01:04:08And on a Velocet, I think it's like 25 foot-pounds or 18 foot-pounds for the four studs,
01:04:13long studs that go from the engine case.
01:04:16And remember, everything, all these solid-looking parts are elastic.
01:04:21Very elastic, right?
01:04:22You know, a steel tank, a steel tank, if you overpressure it, if it's a cylinder, you know,
01:04:28with toruspherical heads, it'll balloon.
01:04:33And it'll stay.
01:04:33If you do it enough, it's stretched.
01:04:35It's really fluid.
01:04:36That's why Hammer and Dolly, that's why Hammer and Dolly works.
01:04:39Because you're peeling out the metal.
01:04:41You're squeezing it.
01:04:42You're stretching it.
01:04:43You're stretching the metal.
01:04:44So anyway, you bore it with this compression.
01:04:48And so that when you build the engine, the cylinder is therefore compressed.
01:04:52And the bore is as close to perfect that you can do with your boring bar.
01:04:57And there's, you know, you, Nicosil played it like Millennium does Nicosil.
01:05:00You, Nicosil played it.
01:05:02Nickel, silicon carbide.
01:05:04Very hard.
01:05:05Very beautiful when it's done right.
01:05:08And you put a, you bore it and then put a plateau finish on it,
01:05:11which means you're knocking off the highest disparities.
01:05:16Yeah.
01:05:16And, and take a drink, folks.
01:05:20You're knocking.
01:05:21So if, if this is the point, you're knocking the top of the point off,
01:05:25but you're also leaving a reserve in the texture of the surface for oil.
01:05:29It's pretty cool.
01:05:30Yeah.
01:05:31And you make, the point of all this blah, blah, is that you're making a perfect chamber.
01:05:35You're getting rings that go inside of there that fit that circular bore beautifully.
01:05:41And you have a very wonderful, I am a chamber, not a snob, but an elitist.
01:05:46I'm a chamber elitist.
01:05:50I want great ceiling.
01:05:52And when I did all of that work to that Velocet, an air-cooled 1954 motorcycle,
01:05:58the oil stays clean practically forever.
01:06:02It doesn't change color because nothing.
01:06:05Isn't that a son of a gun?
01:06:06Nothing is getting by the rings.
01:06:08Virtually nothing.
01:06:09Very little is getting past the rings.
01:06:11Well, there we were, there we were at Monza in 1981 with a 250, TZ250H.
01:06:20And I thought, let's have a look at these rings.
01:06:23We had a stack of them from, from Yamaha.
01:06:26So one after another, I put them, this was a sunny day.
01:06:31I put them in the cylinder, squared them up with the piston and held them up to the sun.
01:06:36Only about six of them.
01:06:37I couldn't see light past the ring.
01:06:41How about that?
01:06:43We put, we put two of the good ones in and gained RPM.
01:06:50So ceiling is real.
01:06:54Gaining RPM means he's making more horsepower just to clarify.
01:06:58Yeah.
01:06:58And that's how a lot of, a lot of racers will talk, especially two-stroke racers,
01:07:02because you're not looking at a speedo, but you know, oh, I'm pulling, I'm,
01:07:06I'm pulling 11,000 instead of 10,8 on the straightaway and six or whatever.
01:07:11And that's how you know you did it.
01:07:13That's a great.
01:07:14And you add that little bit every lap, say it's a 24-lap race.
01:07:19You have time to take several breaths of air, which means you could win.
01:07:24And those others would be toiling in your wake.
01:07:27Yeah.
01:07:28That's worth some effort.
01:07:30Yeah.
01:07:30Leak down.
01:07:31We could tell you, leak down's part of chamber.
01:07:33So when I raced that BMW last year at Barber, the owner, Dan May, who's the executive director of Arma,
01:07:40it's a BMW R75 slash five.
01:07:42We have a video you should go watch on Sega World's YouTube channel of me doing that.
01:07:46And, um, that flat twin, he, uh, he had the cylinders, uh, re-nicacilled at Millennium.
01:07:53I don't know if he replaced the pistons, uh, but certainly re-ringed it, did the top end essentially before I raced it.
01:07:59And he showed me his leak down results of 0%.
01:08:04And I called Bia.
01:08:05I was like, no way.
01:08:07And he's like, no, I'm not, I'm not messing around, man.
01:08:090% leak down, meaning nothing got out.
01:08:11You inflate the cylinder to a pressure and then you measure the drop.
01:08:14And, you know, your fancy boys would be like, oh yeah, I got 3% or I got 5%.
01:08:19And if it's more than that, that's not good.
01:08:21You're kind of like, oh, I should, I should freshen this up.
01:08:24Two stroke.
01:08:24It's just like re-ring it, put a cylinder on it.
01:08:26I miss those days.
01:08:29I miss the circuit.
01:08:29Yeah, you want your, you want your engine to hold pressure like a scuba tank does.
01:08:35And that's why, yeah, that's why seating the rings, particularly in the old days when you had, you know,
01:08:40you were putting a crosshatch on it and you don't want to use your fancy low friction synthetic oils for break-in
01:08:47because you actually want the rings.
01:08:50You don't want a shadow, especially on a fat, you know, a fat ring like these.
01:08:55You can run an engine.
01:08:56You can run an engine.
01:08:57I had to take apart my Velocet so many times, take a drink.
01:09:01I had to take apart that bike so many times.
01:09:03I got to look at the rings after certain runnings and there would be shadows.
01:09:09So what you want is the whole ring to be perfectly shiny all the way around.
01:09:12So hold it up in the sun and look at the edges of the rings that are rubbing against the sun.
01:09:17You want it to be shiny and wonderful, mirror-like.
01:09:20And what I was getting was areas where they were gray.
01:09:24And if they're gray, they're not making contact.
01:09:26Something's getting past.
01:09:27And that's how your damn oil gets dirty.
01:09:29And it's also how the oil will make it past into the chamber and do yuck.
01:09:35Here we get to use the word intimacy.
01:09:38We want intimacy between the piston ring and the cylinder so that there is no room for a third party.
01:09:45So during World War II, the engines on the B-29 bomber, which was used in the Pacific part of the war, had a lot of problems.
01:10:02And the one tool that best predicted disaster was static leak down because it would tell you, you have a valve, an exhaust valve seat that has moved sideways.
01:10:18So you have one point of contact.
01:10:21Everything else is gray.
01:10:24Or the exhaust valve seat has become oval.
01:10:30You have two points of contact.
01:10:32Is that a lot better?
01:10:33I don't think so.
01:10:34So they would leak down test those engines and they'd be able to, the tester would hand the crew chief a sheet telling which cylinders should be changed.
01:10:47And they'd just pull those cylinders off and put new ones on.
01:10:50Oh, I, I had a friend with this tool.
01:10:54It was called the motor meter.
01:10:56I think it was called the motor meter engine meter.
01:11:02It was a compression tester that had a little trace.
01:11:07You put a piece of paper in it and you, you do your compression test.
01:11:12It would swing a little pen.
01:11:14Yeah.
01:11:16And it was great.
01:11:17Oh my gosh, it was a great.
01:11:18So you put the little card in.
01:11:20I just loved using it.
01:11:21And you just, you went one, two, three, four, five, six, seven, eight.
01:11:24I'd use it on a Cadillac 429, 1964.
01:11:28They, when they moved the accessories to the front, they put the distributor in the front because on previous models on the 390, it was at the rear.
01:11:35They did a bunch of improvements on the 64, including a turbo hydromatic 400 first year for that long live, wonderful, uh, automatic transmission, but, uh, the motor medic.
01:11:44And I, I had great compression.
01:11:46Yeah.
01:11:47One, whatever it was, 140, 140.
01:11:49130, 138, 70.
01:11:52Oh.
01:11:54And I still have that piece of paper in my Cadillac file even when I sold the car forever ago.
01:11:58Sure.
01:11:58But just that, that, that week, that we cast trace.
01:12:01So the bottom line here is, uh, it sounds boring working on sealing, piston to cylinder sealing, but it is actually supremely important because what's the point of flowing a lot of intake CFM, flowing a lot of exhaust CFM, having a high compression ratio?
01:12:23So if you're just letting the compression pressure, if you're just letting the compression pressure piss away because the springs aren't sealing against the cylinder wall, criminal.
01:12:34No, it's not for everyone, but for those of whom it's for, it's really for, and also, it's nice to see others doing it and not have to do it yourself.
01:12:46Yes, it's important.
01:12:50It is.
01:12:50It's just, you know, a lot of, a lot of the fancy people in engine building kind of, I don't know, self-deprecate a little bit by saying, I'm not that smart.
01:13:01It's just attention to detail.
01:13:05Right.
01:13:05You know, I don't, intelligence is an interesting subject.
01:13:08It is.
01:13:11Yeah.
01:13:11Feel, emotion.
01:13:12How does it all work together?
01:13:14How many watts of energy do we use to run this thing anyway?
01:13:18It's fairly expensive.
01:13:20That's what they tell us in biology, that the brain uses a large fraction of the body's available energy.
01:13:27So, sort of like these AI centers, they're putting in gas turbine combined cycle units right and left, talking about having private nuclear power plants to run AI.
01:13:40These are just the crude beginnings of artificial brains, crude beginnings.
01:13:48Yeah, I mean, I think if you, if you think about it, you know, bacon or a pork shoulder or a really nice brisket with all its fat content is kind of the uranium of foods, is it not?
01:14:03Yeah.
01:14:03It just does lead to deposits, though, combustion deposits.
01:14:07The old Eskimo gentleman, I know we're not supposed to say Eskimo anymore, but his name was Kisik.
01:14:16And in describing a hunt, he was describing the animal first.
01:14:23He said, talk about fat, because a nice fat animal ready for the beginning of winter is the ideal for eating, because it gives you maximum calories.
01:14:36If you're hunting every day, if you're trotting behind the sled dogs, you've got to have calories.
01:14:45Well, it's just, can you give people context as to why you might have been talking?
01:14:51Oh, the family went to Alaska in 1952 when I was 10 years old, more or less.
01:14:58And we went to the North Coast and we were there for a couple of months.
01:15:07And there was a gentleman in his family who had been in Barrow.
01:15:14Barrow, he said, too much movie.
01:15:16So they went back to their fundamentals and each day he would walk a number of miles to a particular place where he could get water that he liked the taste of to make his tea.
01:15:32And he had sled dogs.
01:15:37They were crazy, which you always hear about them, because there they are, staked out.
01:15:42They get food sometimes.
01:15:45And it was an adventure.
01:15:48I can't imagine.
01:15:48How'd you get there in 1952?
01:15:50We drove to Fairbanks.
01:15:54We flew from there to Bettlesfield.
01:15:57But what did you drive to Fairbanks?
01:15:58Oh, 51 Kaiser.
01:16:00Oh, yeah.
01:16:02With, what is it, Gold Seal 6, Continental Gold Seal 6.
01:16:08Yeah.
01:16:09Side valve, like we started talking about in the 1920s.
01:16:12It's so interesting because you think about this 1951 car.
01:16:17That's all we had, right?
01:16:19It was a new car.
01:16:20You drive it to Alaska.
01:16:22So people look at me driving around in my 89 like, you drove that here?
01:16:25You know, somewhere out far afield.
01:16:27Or the Velocet, I'm riding up Pacific Coast Highway.
01:16:29I left before dawn, and I got the Deachan's Big Sur Inn, which is a great place to eat, especially if it was cold.
01:16:36And it's a great place for breakfast, especially for me.
01:16:40And I pull up on my 54 Velocet, and I'm getting out, and I'm going to eat breakfast.
01:16:44And I'm pulling off, and I got my bell staff because it's misty and cold, and it was a little rainy.
01:16:49And I got my bell staff jacket, and I'm all windblown, take off my helmet.
01:16:54And this guy pulls up in a very fancy Porsche, and he gets out of the car, and he's fascinated by this old motorcycle.
01:17:02He's like, man, what is that?
01:17:03And I'm like, oh, I tell him what it is.
01:17:06He's like, you rode that here?
01:17:08Where'd you come from?
01:17:09And I'm like, oh, I came down from LA, Orange County.
01:17:12He's like, what?
01:17:14And this is like 10 years ago, and this is in 1954.
01:17:19It's like 50 plus, 50, 60 years, 50 or 60 years old.
01:17:24And there you are using it, but that's what people did.
01:17:26And I've had my problems.
01:17:27Don't get me wrong.
01:17:28Anyway, it's just always great to hear like, yeah, of course you had a 51 Kaiser driving to Fairbanks.
01:17:35Carry on.
01:17:35New car, yeah.
01:17:36Yeah.
01:17:37And we flew by DC-3 to Battlefield in the interior, but south of the Brooks Range.
01:17:45And then my dad's friend and sometime author, Bud Helmrichs, came and got us with the Cessna 170.
01:17:55And we flew into-
01:17:57Great push plane.
01:17:58Yeah, we flew on floats at the time.
01:18:01And we flew to the North Coast in that.
01:18:05And flat six.
01:18:11It really looks strange because in that coastal land, it's perfectly flat.
01:18:19And you can look around 360 degrees and there's no evidence of humanity.
01:18:26Nothing.
01:18:28It's just yourself.
01:18:31Kind of cool.
01:18:33It is.
01:18:34Yeah, what was that?
01:18:40That was a Continental, I think, in the 170.
01:18:48I think it was a C-145.
01:18:50I think it was a C-145.
01:18:51They used to name the engines by horsepower.
01:18:53But I think it was 300 cubic inches.
01:18:57So now they would call it a different name.
01:18:59Like, Continels are usually an O.
01:19:03It's probably an O-300.
01:19:03Yeah, O numbers.
01:19:05Yeah.
01:19:05Well, they had combustion chambers, too, folks.
01:19:11That's why we're talking about them.
01:19:14Well, thanks for listening.
01:19:16That's inside the hot room.
01:19:21And it's where it all begins and ends for us, really.
01:19:24It's everything around it is all concentrated on.
01:19:28We compress the gas.
01:19:29It has fuel in it.
01:19:31We ignite it.
01:19:33It adds heat to the gas.
01:19:34Its pressure rises.
01:19:36And then we let that gas press the pistons down and spin the crankshaft.
01:19:42And what an emotion it brings to us, for some reason.
01:19:47Yep.
01:19:47I think it's worse.
01:19:49I think it's because we associate it with high-speed motion, which, if you're that kind
01:19:54of person, we find exhilarating and wonderful.
01:19:59Is there a better feeling than clicking into seventh gear?
01:20:05Well, thanks for listening.
01:20:07Yeah, well, thanks for listening.
01:20:08We'll catch you next time on the Cycle World Podcast.
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