piston damage question

[Belgian1979]

Going to venture to say that this issue might have been caused by wrist pins sticking from either inproper clearance or expansion of that wrist pin for some reason. I would venture to say that it stuck in a certain position and tore at the top of the piston. The rod that exploded might have galled the pin and stuck it so bad that it locked/siezed it onto the small end shattering the rod.

As stated this is an engine with an experimentational wrist pin (steel outer shell with an alum inner)

This would seriously concern me. Why would someone do such a thing?

Lightening/reduced weight.

[Warp Speed]

Going to venture to say that this issue might have been caused by wrist pins sticking from either inproper clearance or expansion of that wrist pin for some reason. I would venture to say that it stuck in a certain position and tore at the top of the piston. The rod that exploded might have galled the pin and stuck it so bad that it locked/siezed it onto the small end shattering the rod.

As stated this is an engine with an experimentational wrist pin (steel outer shell with an alum inner)

This would seriously concern me. Why would someone do such a thing?

Lightening/reduced weight.

VERY POOR decision in most ANY combo........let alone a Blown Alky deal!!!!!!!

[Dave Koehler]

Can you show us a picture of a good pin itself?

[robert1]

I don't think they are aluminum wrist pins. Who's ever even heard of such a thing. The shop that gathered this stuff up knew about putting buttons in the skirts they surely would have known not to use aluminum pins. I think early on there was some confusion about the buttons being the pins.

[Dave Koehler]

Kind of what I was wondering. Just wanted verification.

[avengerengines]

This has been posted on the Vette board 2yrs. ago with lots of pictures.

http://www.vettemod.com/forum/showthread.php?t=7088

[robert1]

Better pics. I still don't see an aluminum pin.

[Belgian1979]

Better pics. I still don't see an aluminum pin.

You can see the 2 colors : outer steel shell which is coated. Alu insert. There is a hole in it to have some communication of pressure left to right. There is no mistake in this aspect. It was manufactured by the shop that asked for the coating.

[SchmidtMotorWorks]

Going to venture to say that this issue might have been caused by wrist pins sticking from either inproper clearance or expansion of that wrist pin for some reason. I would venture to say that it stuck in a certain position and tore at the top of the piston. The rod that exploded might have galled the pin and stuck it so bad that it locked/siezed it onto the small end shattering the rod.

As stated this is an engine with an experimentational wrist pin (steel outer shell with an alum inner)

This would seriously concern me. Why would someone do such a thing?

I would look for more data to support or dismiss this possibilty.

[Dave Koehler]

Better pics. I still don't see an aluminum pin.

You can see the 2 colors : outer steel shell which is coated. Alu insert. There is a hole in it to have some communication of pressure left to right. There is no mistake in this aspect. It was manufactured by the shop that asked for the coating.

Are you saying those are not push in aluminum buttons separate from the actual pin?
You have had the pin only in your hand?

since this is a 2 year old court case what was the outcome?

[fdicrasto]

Aluminum pin buttons have been around for decades,eliminating conventional pin locks such as spirolocs,tru arcs,etc. I am seeing some detonation causing the so called scratches. The burning look is pretty obvious. No spun bearing on the broken rod, who knows what caused the blow up. Ridiculous that someone could be sued over this. If the rods had a few too many runs you can never tell or predict an aluminum rod failure which may have happened bad tune or not. Thats my take,based on decades of my own observation. Phil D.

[robert1]

Belgian yes there are aluminum buttons in the end of the pins. This is completely normal. Usually they are turned down on the ends and slide into the pin. What you are seeing that makes you think they are aluminum is the button.

[PFC1]

While it appears that the pins are gaulded, which is probably what destroyed the rod. The scorched marks on the piston are from being too lean, too much timing, inadequate fuel or all of the mentioned creating detonation which in turn made the piston crown expand too much.

Bret

[Belgian1979]

The same type of buttons as on the piston skirt was used in the pin ends.

I saw the plans of the pins. They are actually what I described : steel outer shell with an alu inner. No doubt about that. Like I said this is part of an experimentation they did. I have a hard time believing this as well. In my opinion you must be a fool to use an alu pin in an engine like that, but who am I

Claim was made towards the insurer in liability of the firm that did the coating. That's were I came in. The contractual stipulations aside, you can see where the alu of the rod was deposited on the pin (see the link to vettemod). It's absent in the area where the hole in the small end is. This leads me to a oiling issue among other issues. I talked about this a length with Kevin and we saw some evidence of a shift of the bearing which could have restricted splash oiling to the pin of which the rod broke. The pin the bearing cap was out. I'm pretty sure they do run a vacuum pump as well although they wouldn't admit to it...

We compared a piston with an original pin, which slid through without effort. This pin was made too large and would not slide in except when using some effort. This makes a huge difference with regards to liability as in my opinion the builder made a big mistake of putting the pins in beside the obvious dimensional problems.

I have been building my engine and my reasoning is that the one who builds the engine and puts in a part without verifying if it fits properly is at fault.
There are 3 parties in this story : the raceteam vs the shop that made the pins vs the firm that did the coating. The shop has a racing program as side business deal.

When I saw the parts, there were no suitable mics available so I had to measure it with a digital caliper which only gave an idea at best. If a court expert will be put on the case I will bring my own mics that I used to measure my pins and bores. It will clear up a lot.
Some detonation and too much timing, leading to a possible extra amount of heat production could have been the proverbial straw that broke it's back.

[Dave Koehler]

While I would still like to see these pins I can say that the coating had nothing to do with the demise.
You covered all the other possible reasons. Those racers are in the wrong business. They need RC cars that they can exchange at Walmart.