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flex plate bolts wont stay tight ...I have fought this problem for years with a 8 bolt flex plate sfi approved ,3 passes and they are beating up the back of the block ,,,they are red locktighted and tight ,Jim VanZee is now having the same problem ...one guy years ago said buy "the wheel " but I never did Jim said some guys say it isnt the flex plate its the Harmonic ballancer ,,,whose got the real answer ,,,,???

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I would say find the common things about both of your set ups.
If you have the same engine guy, that may narrow down the balancing.. Same converter company.?? T/F or Glide..






Chris..

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My bolts never come loose. They have no thread locker. Why are there hundreds of cars out there W/O locktite that have no issue? If they come loose with locktite there's a real problem. The only real cause that I can think of is harmonics whether it's a balance issue, detonation, or other. Oblong holes shouldn't matter,the bolt is not driving the plate,the clamp load is what holds it tight.

Doug

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Respect your opinion...but if oblong holes do not matter then they would come from the factory that way...

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Respect your opinion as well...but most factory holes are anything but perfect in size relationship to the fastener employed. And why would they spend more on an oblong shape anyway, if not needed? Factory stampings are about cost containment.

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Ran into this last year after changing convertor in a customers car. The convertor fit fine on a 6 bolt crank but on an 8 bolt, the flexplate to convertor bolts hit the hub on the convertor before the bolts into the convertor were tight.
Look to marks in that area of the convertor from the bolt heads. Thin spacers between the two fixed the issue but we used longer bolts to ensure enough thread engagement.


I have absolutely seen this as a problem with several cars. The bolt heads are barely rubbing on the rounded part of the converter housing, and they will back out almost every run, or every couple runs.


I think its already been said here.

1) Check for interference of bolts/TC cover
2) Balancing/damper ( we have no idea on this one, only YOU know if the shop balanced it.Get the records from them and see if anything looks suspect)
3) I agree 100% with torquing the bolts everytime. A converter bolt SHOULD NOT need red loctite to STAY IN. Only to be a preventative safety measure.

My

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Ran into this last year after changing convertor in a customers car. The convertor fit fine on a 6 bolt crank but on an 8 bolt, the flexplate to convertor bolts hit the hub on the convertor before the bolts into the convertor were tight.
Look to marks in that area of the convertor from the bolt heads. Thin spacers between the two fixed the issue but we used longer bolts to ensure enough thread engagement.


I have absolutely seen this as a problem with several cars. The bolt heads are barely rubbing on the rounded part of the converter housing, and they will back out almost every run, or every couple runs.


I think its already been said here.

1) Check for interference of bolts/TC cover
2) Balancing/damper ( we have no idea on this one, only YOU know if the shop balanced it.Get the records from them and see if anything looks suspect)
3) I agree 100% with torquing the bolts everytime. A converter bolt SHOULD NOT need red loctite to STAY IN. Only to be a preventative safety measure.

My

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To go into detail a little further we had an aftermarket damper that looked great last year but the outer ring spun 180 degrees. Double check top dead center to see if the outer ring could be moving. An ATI damper is going on this years engine.

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Like everybody else said and check to make sure the converter bolts aren`t bottoming out, i.e. too long, I had this problem that I kept cracking flex plates, turns out the bolts were one thread too long, we cut them , put loc tite on them , retightened them with an impact thru the starter hole ( Like Mr P body said) and haven`t had a problem since.

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