Tech miss-directions to win races - and make a lot of money

[Kevin Johnson]

First block distortion. Our measurement system was always plagued by vibrations so we had to do quite a few tests then, by averaging out results, come up with a number. Unfortunately the accuracy of this was always questionable but it was better than 'no idea what-so-ever'. On our Cosworth block the twist at 270 hp and 7000 rpm was tested five times over three consecutive days. Answers, going up the scale of the measured twist were, - .0045, . 0077, .008, .0082, .0126. Any one of those numbers could have been right or wrong but they were at least numbers we could re-produce in a static test. With the block mounted on a giant pre WWII horizontal mill we put the seen twists into a long block assembly less crank. With dial gauges measuring the mains defection we saw up to 0.004 out of alignment from front to back to center main.

The question is what would this be worth if we were to fix it? If it was that much what is the point in worrying about the mains alignment down to the last tenth of a thou when its on the engine stand.

There seems to be at least two different issues that may or may not be related (distortion of a block under load and power loss from prior distortion due to main bore misalignment). An initial pertinent question is whether the engine tested had pre-existing main bore misalignment.

Aside: I finally found Bill's (bill@bhj) post from 2010 viewtopic.php?f=15&t=22589

I can only partly answer the question -
While testing OEM crank dampers on an inline 6, (292 Chevy) we used to make a quick sweep across the rpm range to spot the general pattern of where the torsion peaks were, then go back and go very slowly across the rpm band where the worst peaks were to get a more exact reading of where those peaks were. We wanted the frequency of those peaks for fine tuning the damper. Inline's are not alone here, I just use it as an example - They usually had several nice peaks to contend with.
If we would set the engine directly on a high peak, (say .6° p-p) we would see that peak slowly rise (~20-30%) and see a corresponding rise in the oil temperature ( say 20-30°) Since the engine owner didn't want to pursue this any longer than necessary, we never sat there to see how high either value would go.
All it proved was that the torsion was enough to make each of the bearings into a small viscous damper which would absorb some energy at the expense of heating the oil in the bearings and consequently in the pan. ...

I mention it because it is another possible confound whether at 7000 rpms the YB has resonance of any sort with the rotating assembly.

[David Vizard]

First block distortion. Our measurement system was always plagued by vibrations so we had to do quite a few tests then, by averaging out results, come up with a number. Unfortunately the accuracy of this was always questionable but it was better than 'no idea what-so-ever'. On our Cosworth block the twist at 270 hp and 7000 rpm was tested five times over three consecutive days. Answers, going up the scale of the measured twist were, - .0045, . 0077, .008, .0082, .0126. Any one of those numbers could have been right or wrong but they were at least numbers we could re-produce in a static test. With the block mounted on a giant pre WWII horizontal mill we put the seen twists into a long block assembly less crank. With dial gauges measuring the mains defection we saw up to 0.004 out of alignment from front to back to center main.

The question is what would this be worth if we were to fix it? If it was that much what is the point in worrying about the mains alignment down to the last tenth of a thou when its on the engine stand.

Trying not to get diverted here but continuing on from my previous 'tech' per above post:-

A friend of mine who was a really good championship winning engine builder gave me a call and asked if I would like to test their championship leading Mini- cross car at Cadwell Park. This road course is probably my favorite as it is very much like the roads and lanes around where I used to live in the Cotswold hills, namely all bends and not much in the way of straights. Now the engine was coming out of the car after this outing so I accepted the offer. Had a great day with at least 2 hours on the track.

After this I went over with my engine builder friend to his shop where the next day the engine was to be R & R'ed for the final round (winner of this race takes all)' So day or two later i get a call informing me the center main saddle on this Mini engine was just a shade over 3 thou off the center line of the other two bearings. This car had been pretty much dominant with this main bearing misalignment so the expectation with this much error it would be even more competitive for the final round. A few more days on he calls and sounds a little disappointed. Fixing the miss-aligned center main showed absolutely no difference in the output curve. It was 54 hp before and 54 after. The torque curves laid one over the other.

conclusion - at least 0.003 thou was not signiffican IN THIS PARTICULAR CASE.

As for backup on this assumption was over to collect some parts from legendary mini engine builder Paul Ivey. Paul did a lot of testing for the factory. After I told of the aforementioned test he relayed to me that he had done some similar tests for the factory on miss alignment but, in this instance, with the cranks center main out of alignment in steps of 0.001 at a time. The base engine was a stock 850 mini unit and cranked out about 30 hp. At 0.003 main bearing miss-alignment no power loss was measurable. It was not until a crank with the C/main 0.004 off that any power loss was seen. As I remember the loss at this point was at or a shade under 2 up. As a % that would have been about 7.5%

As to how this related to the Cosworth YB motor we never got around to testing as there was a big rule change in the wind for the following year which would prohibit the use of turbo motors.

However, within the context of this thread there were a lot of uses of regulations that would be very much in the favor of a more informed team.

Last point - what would this deflection look like on a cup car motor - anybody got some thoughts on this before I pitch mine into the public arena!

DV

[David Vizard]

OK let's have the moral view of this 'disinformation' deal

Was down in Florida for the 500 and a short Vacay. On the following weekend I thought I would go see Harvy Crane and say goodbye.
When I got there he was in a tearing hurry to tell me that his cam won the 500. He was a little surprised it had worked well but it had 'leack out' he had sold quite a few replica's.

Not to long after that ( 6 months maybe) I was over at the team that had won the 500. Can't remember who won - might have been Junior Johnson's team - just too long ago but for sure I mentioned 'the cam'. Their engine builder said "there's the cam over there on the shelf. Never did or even intended to use it because it has only a slim chance in hell of actually working. But it sure has led the other guys up the wrong path. I know of some of our competition that has already spent a small fortune and a lot of time trying to find the combination to make it work. So long as they keep trying we are in good shape!"

DV

[Stan Weiss]

Talking NHRA Drag racing. Have no idea what goes on now. But years ago when people put a decal for cam company "X" on their car because they payed contingency money but they were really running a cam from a different company what was that?

Stan

[Kevin Johnson]

Not trying to be a pain here but I went through an extended period of trying to analyze what distortion Luerenbaum's reverse torsion crankshaft test machine was actually imparting to crankshafts.*

* Luerenbaum's work published in Germany and cited by C.F.Taylor. I purchased an original German copy that was surplus from the US Government (ex Library of Congress). Photographed pages below. Needless to say, with the thorough bombing in the war the original records for the experiment were likely destroyed so one needed to work off a photograph of the apparatus.

http://www.crank-scrapers.com/Taylor%20MIT/Luerenbaum/


The description of misalignment in the bores is open to multiple yet consistent interpretations. This is why in technical journals an exact diagram of the testing apparatus and exactly how samples are mounted/constrained is so important (for other labs to reproduce the results).

[Tuner]

Talking NHRA Drag racing. Have no idea what goes on now. But years ago when people put a decal for cam company "X" on their car because they payed contingency money but they were really running a cam from a different company what was that?

Stan

Probably a Comp Cams decal and an Isky or T. Willy cam.

[modok]

Thanks for sharing David.
Guys seem to be very misdirected by this particular story, and THAT'S what you call IRONY

I do a LOT of line-boring, and crankshaft straightening, thus have some grasp of what can and does happen, so I am finding it a very entertaining subject.

[David Vizard]

Kevin,
We did not use anything as complex as this. The description of misalignment in the bores is open to multiple yet consistent interpretations. This is why in technical journals an exact diagram of the testing apparatus and exactly how samples are mounted/constrained is so important (for other labs to reproduce the results).

The most expensive part of the test was the 14.000 lb plus mill and we only borrowed that. There was no intent to give away any results here unless it could slow down our over budgeted competition. We did, with a scrap YB block. try a miss-alignment of 2 thou in the center main 1 thou in the #2 and #4 main and zero in 1st and 5th. Rotating the crank was really hard to do - about 80 lbs-ft as I re-call. To get it to rotate 'normally' took about 150 psi oil pressure.
DV

[superpursuit]

[quote="David Vizard"
However, within the context of this thread there were a lot of uses of regulations that would be very much in the favor of a more informed team.
DV[/quote]

David. Any chance you could give some examples of the above. Thanks.

[Kevin Johnson]

Kevin,
We did not use anything as complex as this. The description of misalignment in the bores is open to multiple yet consistent interpretations. This is why in technical journals an exact diagram of the testing apparatus and exactly how samples are mounted/constrained is so important (for other labs to reproduce the results).

The most expensive part of the test was the 14.000 lb plus mill and we only borrowed that. There was no intent to give away any results here unless it could slow down our over budgeted competition. We did, with a scrap YB block. try a miss-alignment of 2 thou in the center main 1 thou in the #2 and #4 main and zero in 1st and 5th. Rotating the crank was really hard to do - about 80 lbs-ft as I re-call. To get it to rotate 'normally' took about 150 psi oil pressure.
DV

The mill would be a good example. How was the block mounted so as to create an axis of distortion co-linear with the central axis of the crank? It sounds simple but is actually a very complex problem.

A center main that is out of alignment with two co-linear end bores could be translated anywhere in the x-y plane that bisects the z-axis (crank centerline).

I ran into a related issue when studying the 928 sinter forged rods where the big end bore to small end bore centers was consistent but this pair of bores was randomly translated in the plane of the rod forging.

[David Vizard]

Kevin,

Basically the block was mounted at the flywheel end on a 4 inch square mild steel bar about 2 ft long. ths was bolted with about 3/4 bolts to the bed of the mill.
The back end of the block was then bolted very stoutly on to this 4 inch square bar. the other end was supported by a round bar the inside of a large roller bearing that fit inside #1 bearing housing. The round bar also rested on a heavy v block about a ft or so out from #1 bearing. From here is was a question of a stout lever arm on the block and a torque load the duplicated the block twist. The motion of the mains was recorded on five magnet mount 0.0001 increment dial gauges on the mill bed. All somewhat crude but non-the less repeatable. Might not have been super accurate but it was a whole lot better than no idea!

DV

[Kevin Johnson]

The first thing that I would question is why the lever was not attached to the round bar so that the torque was introduced to the block via the first main rather than a location on the block (engine mount?).

The issue came up with respect to the reverse torsion testing because modern simulations of stress did not match the empirical testing results in ranking the designs and materials.

[David Vizard]

The first thing that I would question is why the lever was not attached to the round bar so that the torque was introduced to the block via the first main rather than a location on the block (engine mount?).

The issue came up with respect to the reverse torsion testing because modern simulations of stress did not match the empirical testing results in ranking the designs and materials.

Kevin,
You might be missing the point here. The object was to get my engine cranking out more power than the rest of them out there. This was in an effort to win races not to do and SAE paper on block distortion. This was a down and dirty test for sure. As for the point at which the loads were input input the block the front of the block proved to be the most convenient. this 1989 and I had now idea whether or not any SAE papers existed on block distortion. I did what I did when I had the opportunity and used the measurements gained to further my cause to win races - which did in that one case.

You brought up the subject of bore distortion as weel a will back.

I have some evidence that SUGGESTS the bores on my 289 only distort about an average of 0.0015. I cannot say with much confidence in what form they distort but I don't think the overall distortion is as much as is commonly calculated. As for how I came up with this I'd rather not say as it is definitely proprietary.

[David Vizard]

Guys,
I just want to remind every one we are trying to come up with enough good tales that would make a book. (please check my original post) I have a publisher that will look at the MS I have a prospective person to actually assemble the books contents. If we use the 'Smokey Yunick' format (ie don't correct grammer or spelling) then this book should go together really quick. I had envisaged half the royalties to who ever does the book and the rest going to a charity of this sites members choosing.

Please think about that before throwing any negatives into the fray. If you have a compliant PM me - I am sure we can sort it out to the best.

DV

[Rosenbluth]

I have a friend that used to work in a tire shop. He raced IMCA mods, and would take the sticker off the tires he'd sell and put them on his mod tires so it looked like he had brand new tires on for every race.

I knew a guy that made a "cap" that would go on the LR hub, where the drive flange bolted up, he had a shop rag over the cap, then duck taped around it as if it was a "secret" drive flange.