piston damage question

[Belgian1979]

What you see is common lean and the piston rock does not help Buttons on the pistons is old time not really needed if builder understands this type of engine Yes those are alluminium pin buttons vey commonly used in this type of build. Those pins are very familiar steel dlc coated all the rest asside this is common rod failure from loss of oil preassure [locating pin ripped out] the scuff marks could have happened after from the exp. Seen all of this many times over. Mike Kosky

In the age of anodizing and coatings I kind of wondered about the skirt buttons myself. The last set I had was in the early 80s.

Oh, and welcome Mike Kosky, long time blown alky racer.

JE (manufacturer) advised against them as it would weaken the skirt. One of the pistons had a chunk broken off originating from a hole where a button was.

Just talked to the lawyer handling the case. Looks as if I be put up as expert witness.

[MadBill]

One of the ironies here is the attempt to minimally reduce reciprocating weight via a highly-dubious composite pin strategy while making the pins much longer/heavier than necessary in order to use buttons rather than pin locks. Also a hollow dome version of a strut-type piston such as pictured (this example ordered from Wiseco by Roush in 2002) Vs. the 40+ year old design selected would cut the pin length in half while knocking off maybe 250 grams...

[twl]

One of the ironies here is the attempt to minimally reduce reciprocating weight via a highly-dubious composite pin strategy while making the pins much longer/heavier than necessary in order to use buttons rather than pin locks. Also a hollow dome version of a strut-type piston such as pictured (this example ordered from Wiseco by Roush in 2002) Vs. the 40+ year old design selected would cut the pin length in half while knocking off maybe 250 grams...

Yes, that does seem to be going in two different directions with that strategy!

[Strange Magic]

Look at the crack in the ring land

Am I missing something here? I'm not seeing a crack. Are you talking about that squiggly/chatter line that starts above the top ring and continues down through the second ring land and onto the third ring land? if so, from the picture it appears to be the end of the ring dragged down it from ring installation.

P.S. Look at how thin that wrist pin is!! A guess would be about .090-.110 thick.

pic below:

[Strange Magic]

The small end gets its oil from splash, which comes from the side of the rods on the big end. If the bearing shell shifts because of the locating pin being ripped out (or simply not assembled) it can work itself to the side causing splash to the top being reduced.

THIS IS NOT WHAT HAPPENED

I will tell you this, that almost all of my engines produced carry significant crankcase vacuum (north of 20) and the source of the vacuum is at the lowest point of the dry sump pans. The vacuum pumps are plumbed down at the pans as well. With that said, these engines see little to no oil at and around that wrist pin area. We run super light ring packages and can't afford for oil to really be on the wall either or around that pin area.

Dave this is not my engine.

It's a case I have to handle. A case that should not have made it into court.

I would be very concerened for the end user/owner of this engine, because based upon some of the suggestions you have made, many are just not consistant with the findings that a professional engine builder would have.

[robert1]

It's a case I have to handle. A case that should not have made it into court.[/quote]

I would be very concerened for the end user/owner of this engine, because based upon some of the suggestions you have made, many are just not consistant with the findings that a professional engine builder would have.[/quote]

Certainly needs a better grip on things. I still would like to see a good pic of the pin with NO button installed. I think the pins are coated and somehow they are thinking this makes them thin wall pins. The only pins I have ever seen even close are Titainium with a steel sleeve. I see no crack as well.

[robert1]

One of the ironies here is the attempt to minimally reduce reciprocating weight via a highly-dubious composite pin strategy while making the pins much longer/heavier than necessary in order to use buttons rather than pin locks. Also a hollow dome version of a strut-type piston such as pictured (this example ordered from Wiseco by Roush in 2002) Vs. the 40+ year old design selected would cut the pin length in half while knocking off maybe 250 grams...

All of the boxed pistons I've seen have way thicker pin walls leading to very little weight loss.

[Belgian1979]

It's a case I have to handle. A case that should not have made it into court.

I would be very concerened for the end user/owner of this engine, because based upon some of the suggestions you have made, many are just not consistant with the findings that a professional engine builder would have.[/quote]

Certainly needs a better grip on things. I still would like to see a good pic of the pin with NO button installed. I think the pins are coated and somehow they are thinking this makes them thin wall pins. The only pins I have ever seen even close are Titainium with a steel sleeve. I see no crack as well.[/quote]

There is no button in the pins in any of the pictures. The black ring is the steel outer shell, the gray is the inner alu center. That inner is one piece through and through

[Belgian1979]

The small end gets its oil from splash, which comes from the side of the rods on the big end. If the bearing shell shifts because of the locating pin being ripped out (or simply not assembled) it can work itself to the side causing splash to the top being reduced.

THIS IS NOT WHAT HAPPENED

I will tell you this, that almost all of my engines produced carry significant crankcase vacuum (north of 20) and the source of the vacuum is at the lowest point of the dry sump pans. The vacuum pumps are plumbed down at the pans as well. With that said, these engines see little to no oil at and around that wrist pin area. We run super light ring packages and can't afford for oil to really be on the wall either or around that pin area.

Dave this is not my engine.

It's a case I have to handle. A case that should not have made it into court.

I would be very concerened for the end user/owner of this engine, because based upon some of the suggestions you have made, many are just not consistant with the findings that a professional engine builder would have.

Right, piston pins slide metal over metal all the time. No need for clearance either. We can skip oil rings altogether since no oil is needed in the cylinders at all. Heck, why not put no oil in the engine at all, since bearings can slide metal over metal as well.

Did it ever occur to you that besides preventing metal to metal contact, oil also does cool things down ?

Even more so, they told me they used DLC coated steel pins before but they galled up, and it had something to do with their vacuum pump..... When I started asking more questions about that they suddenly went silent...No sir, it still is the coating that caused this.
They went drag racing with a € 50 k motor, but we weren't aware things can (and will) blow up sometimes and don't have the budget for a spare engine. So if it goes wrong there is always someone we can have paying the bill.

[Strange Magic]

Pin coatings are used mostly, and in cases whereas the material being used will gaul/sieze if the barrier of protection within the material is not present (hardness/heat treat). H-11, H13 and 9310 do not need coatings as they can ride free from gauling in that pin bore, if the clearance is set properly and the pin does not distort. C-350 and certain other materials need coatings to prevent it from gauling. Coatings in general, casidium, nikasil, dlc, ect... will not add to the structure or strength of that wrist pin.

p.s. Once again, whomever came up with this brainiac idea to use an aluminum insert for support/strength to back up or stabilize a wrist pin for the shear purpose to rid the pin area of weight, should be shot! what a shame!

[Belgian1979]

Pin coatings are used mostly, and in cases whereas the material being used will gaul/sieze if the barrier of protection within the material is not present (hardness/heat treat). H-11, H13 and 9310 do not need coatings as they can ride free from gauling in that pin bore, if the clearance is set properly and the pin does not distort. C-350 and certain other materials need coatings to prevent it from gauling. Coatings in general, casidium, nikasil, dlc, ect... will not add to the structure or strength of that wrist pin.

p.s. Once again, whomever came up with this brainiac idea to use an aluminum insert for support/strength to back up or stabilize a wrist pin for the shear purpose to rid the pin area of weight, should be shot! what a shame!

It's a stupid idea without a doubt. But I'm not sure that flexing explains this. The galling on the non destroyed piston was towards the outside of the piston pin bore. I would have though it would have enlarged and more towards the inside where the pin is. Didn't see that.

[Dave Koehler]

I just don't get suing the coating company.
Lack of clearance, lack of oil and a spaghetti wrist pin are the issue.
As fast as those pistons change direction you don't think the outside edges would get smoked first with the flex pin?
Pin flexes, clearance goes away (if correct to begin with) and boom.
Having personally had too limp of a pin in high cylinder pressure/hi rpm application before I certainly do.

[Strange Magic]

I just don't get suing the coating company.

You've got to be kidding. Is this whats taking place? A suit against the coating company?

[BrazilianZ28Camaro]

It will be interesting to find out the wall thickness of the steel portion of the pins.

Thin, like 1-1,5 mm.

WHAT??????????

Sorry but the builder assigned his sentence here^^ This pin is a joke.

I have seen evidence of distortion of the pin bore, but 90 ° to the force working on the piston (downward towards the crank) indicating the deformation is in line with the side pressure working on the piston on the downward stroke on caused by the angle between the rod and the crank.... I'm pretty sure this is sufficiënt proof of detonation.

The pins distorted badly, galled on the piston first while the rod was turning the pin. The rod angular movement rotated the pin and at small steps per cycle, and the pin finally locked at 90° of the point of force.When it locked , something should broke or the engine would stop instantaneously.

Man, you should have a deep pockets to test exotic ideas on expensive engines.

[kosky racing]

See you later too many EXPERTS on this forum may the GODs gift you bye