Failed flexplate.....

Thought it worthwhile to post some pics of my son's failed "aftermarket" flexplate & associated damage to the race car. The starter ring disintegrated into several 2-3" pieces, and exited the ultrabell "scatter shield", during the 7600rpm, 1-2 shift in his ultraglide at about 90 mph.

Needless to say, this failure caused an immediate unbalanced condition with high driveline vibration so the run was aborted!

At the end of the track he was able to idle the car back to the trailer & we inspected the damage. Seems like the starter ring gear fractured at one or more of the welds & left the rotating flexplate tangentially. The inside of the aluminum ultrabell is pock-marked and torn(like a carbide burr would do when carelessly head porting!);a piece(s) exited thru the inspection cut out at the bottom and really gouged one of the bottom frame rails; another piece notched the top of the oil pan sump. Now the pan leaks when loading/unloading the car.

After further inspection we noticed that the starter nose gear/shaft is also broken & the oil pump pickup screen became detached from the tube - probably from the high vibration.

In retrospect the [NHRA-required] parts did what they were designed to do, i.e., protect the driver! On the other hand I think the weld quality of some of the aftermarket stuff is questionable......

I hope it wasn't a JW wheel, I just ordered two of them.

It looks like its brittle from the weld(too hot)

Wasn't going to name names, but yes, it was a JW "wheel". It has been in service for ~5 years & has seen ~250 runs behind my hi-comp, hi-winding, W2 headed, R3 block, 416 stroker.

JW says something to the effect that if you run too much compression & the starter kicks back often, the flywheel could be compromised.

BULL [Edited by Moparts - Family Friendly Site - Keep it clean]!

I say: "Just weld/heat treat it better; and considering the price charged, it should be fool[fail?]proof!" Who knows though, these things may come from China/Taiwan/Korea/etc. too....

Try one of these....

Olan @ Reactor..

http://www.reactorproducts.com/mainProducts.html


Chris..

A couple of years ago I was at mobile dragway when a flex plate came apart like that , sent a chunk of the ring gear into the stands hitting a girl in the arm . I seem the sparks from under the car them the scream. Not a good situation. Didn't Fred's come apart also?

We had a few also years ago and blamed the welds on several different flexplates. We sawed off the headers complete and went through the right side torsion bar in one explosion. I went on to build a completely welded one and it failed also.

After furthur studying the breakage I noticed that it originated closest to the converter pad where the converter was flexing the flexplate forward excessively.
Do a check on the thrust bearing in the motor for damage and check the cooler pressure to see what it is.

Hutch

I thought I read some where the Wheel became SFI certified a year or so ago. did yours have the SFI sticker on it? I just recieved both my wheels yesterday and they have the SFI sticker on them.

I'll be sure to change them in three years and send them to the scrap man so no one can but them on thier car and hurt some one

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Wasn't going to name names, but yes, it was a JW "wheel". It has been in service for ~5 years

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Sorry to hear about the damage. I agree that is disappointing. A racing flexplate should be inspected at least every 3 years. The NHRA/IHRA safety rules require SFI 29.1 flexplates (9.99 or 135 mph) that expire 3 years after date of manufacture.