Wrist-Pin Clip Failure

[Denny Trimble]

Has anyone had a wrist-pin clip on Wiseco high-compression pistons spontaneously disappear? This is on an F4.

The Scene:
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom07.jpg


The Back:
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom12.jpg

The Front: (notice the chunk of rod embedded in the case)
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom20.jpg

University of Washington Formula SAE ('98, '99, '03, '04)

[Denny Trimble]

Has anyone had a wrist-pin clip on Wiseco high-compression pistons spontaneously disappear? This is on an F4.

The Scene:
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom07.jpg


The Back:
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom12.jpg

The Front: (notice the chunk of rod embedded in the case)
http://students.washington.edu/dennyt/fsae/thrown_rod_web/images/Ka%20Boom20.jpg

University of Washington Formula SAE ('98, '99, '03, '04)

[HB]

It doesn't appear that it's a wrist pin clip failure but a case failure...the case failed to hold everything together! It looks like you are leaking some fluid, you might want to check that out too.

Dave

HB

[gug]

thanks for these photos. my supervisor has some messed up idea that a good place for the engine would be inbetween the drivers legs. i should now be able to graphically show him one of the many reasons why this is not a good idea. http://fsae.com/groupee_common/emoticons/icon_smile.gif

bad luck with the engine, at least you will have a bucketload of spare parts now...

- the problem with the world is stupidity. i'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety lables off of everything and let the problem solve itself?

[James Waltman]

Damn, that sucks.

We heard about that happening to you guys. I didn't think that the damage to the case would be so extensive. What kind of down time will this cause for you? We have two running cars right now and we were hoping that we could get down there with you guys to drive soon. Maybe the weekend of the 13th-14th (finals will be done). What do you think?

Good luck.

James Waltman
http://dot.etec.wwu.edu/fsae/
Vehicle Research Institute at
Western Washington University

[Denny Trimble]

Hey James,
We're driving this Sunday, but it's a driver cut day so we need the lot to ourselves. We were hoping to finish driver cuts last week, but you see the results.

Next weekend should work out, I'll get back to you.

Also, I just heard from an alumnus about the a-arm failure you saw on the 2001 car a while ago. It turns out a steering rod failed, which caused the a-arms to wrap up.

University of Washington Formula SAE ('98, '99, '03, '04)

[BStoney]

Looks like you're leaking something. May want to get that checked out... http://fsae.com/groupee_common/emoticons/icon_wink.gif

That really sucks, sorry to hear that. Hopefully you have a spare so you can get driving again. Good luck.

University of Cincinnati
bjstoney13@yahoo.com

[karter]

If you use spiral locks they wiil not fail unless they arn't installed correctly and that would be tough to do. internal snap rings (the kind with 2 holes for the plyers) are noted for failing allong with wire snaps. So what happened, did the piston get stuck in the cylinder?????

[Denny Trimble]

The wiseco's come with very simple wire locks. One disappeared, the wristpin worked its way out, and as soon as one end left its bore in the piston, the wristpin cocked and broke off the top of the rod.

These pistons had been installed for over a year, with about 200 hours on them including dyno time, competition in Detroit, and Nationals in Topeka.

University of Washington Formula SAE ('98, '99, '03, '04)

[karter]

Wire locks did well to hold up that long. What usualy happens is the wire vibrates then breaks in half, particulary if the open section is to the side. I have installed them with the section up or down but, I still don't trust them.

[clancy]

Denny, Much simpathy. Don't think you'll be able to save that one.

Sure enjoyed seeing you guys in Topeka.

See ya in Detroit.

Clancy @ The University of Kansas

Clancy

[Denny Trimble]

Clancy,
Thanks for the cinnamon rolls in Topeka. I'll stop by and say hi in Detroit! How's the new car coming? We're starting to get elbow-deep in carbon fiber molds...

University of Washington Formula SAE ('98, '99, '03, '04)

[PatClarke]

Hi all,
Back on line briefly after the Aus comp. More about that later.
Wire clips should always be installed with the gap at the top or at the bottom. If the gap is at the side, piston acceleration will pop them out.
If the clips have a tail on them, cut it off very short, otherwise the tail will vibrate off and do dreadful damage. A slamm relief can be milled into the gudgeon tunnel to permit the removal of earless clips with a sharp picking tool.
I hate to see good engines reduced to scrap.
PDR

Rudeness is a weak mans imitation of strength

[Jackson]

Ok, stupid question:

what are spiral locks? We are probably going with custom pistons, which will undoubtedly come with just the simple wire locks as described above.

Hope you guys have a spare block-- That looks like a bit more than JB weld will handle.

Brian
Washington State FSAE

[Denny Trimble]

Thanks for the advice, Pat, nobody around here had heard that little tidbit. The clips were oriented every which way. By the way, we had just bumped the rev limiter up from 12 to 13, so the increased accelerations of the piston probably got to it.

Jackson, we'll be patching the bigger hole with duct tape as a "form" for the JB weld.

University of Washington Formula SAE ('98, '99, '03, '04)

[karter]

sprial locks look loke internal snap rings except they continue arroundfor 540 deg. see http://www.raceeng.com/Pages/Page_3_4cyl.html