Ok this is crazy, last night I broke a 2nd flexplate. Why are the factory and stock replacement ones so weak? They only seem to last for 50K miles if that.

Where do I buy a heavy-duty flexplate for our cars?

Thanks!

Alex

 

Are you hard on them? Have you been re-torquing them after so long? What part are you breaking? Where it bolts to the crank? I am just curious.

 

I guess maybe but only full throttle launches on the street with street tires, not the track with race slicks or anything, and even these are rare.

No I've never re-torqued them. They are shearing in the middle around all of the bolts that hold it to the crank, maybe about 1/4" away from the bolts all the way around.

 

What did you do to break it ? You can try racingjunk.com they sell heavy duty flexplates for daily driving to towing applications made from thicker gauge steel than oem.

 

Forgot Link

http://www.racingjunk.com/Automatic-...lexplates.html

 

something is missaligned and causing the flexplate to
flex around the crank hub,fatigue,and break...i'd start
checking the tranny bellhousing and pump bushing etc.
to see where the missalignment is.

 

buy a SFI cert flexplate. if you have done anything to make more power AT all!

 

i agree

 

I'll look into it but the 2nd flexplate, rebuilt converter, etc. was installed by the best tranny shop in town who rebuilt my tranny for the 2nd time also only about 30K miles ago. My bell housing is in 1 piece and straight.

Thinking about it, my car is very low, especially the teeth of the flexplate and the TQ converter. I'm perhaps thinking maybe a rock I have hit in the road who know how long ago contributed to it.

 

I'd talk to a manufacturer who can advise on something like new washers and bolts and maybe a different torque spec to lock it down more solidly. Biggest washer and bolt head that fits; flattest washer surface with chamfer at the outer and inner end of the face surface so there's no stress to the surface unnecessarily; loc-tite if they recommend it. Run a steel dust shield so you know when you're coming close to hitting it (and can avoid that particular speed bump, gutter etc.)

And on that lowered car, if you happen to be running a 168 tooth flexplate (both starter bolts are the same length if you are,) then change to a 153 and corresponding starter (unequal length bolts)

You're not running enough power for that to be the issue. Hopefully new bolts, washers and a thicker `plate gets you good for a much longer time.

 

dowl pin locations of engine or tranny could be "off"-
miss-manufactured when these parts were made,
check real close when it's apart-engine will be easy to
check,tranny harder to check since it's input shaft can
move some when not supported.
Found the same flexplate breakage on a '79 malibu
once,had a 267v8-about 120hp-excess HP/abuse not
the cause. Bellhousing bolts were not loose and it was
fully mated to engine-probably tranny bellhousing was
miss-machined and tranny not concentric with engine
crankshaft..

 

i have the same problem, my 92 rs broke two of them from just punching the gas

 

Even though I am going to a T56 I am curious as a friend had broke three before selling a chevy truck he had. I would want to wonder about the misalignment issue but I will not discount it at this point. It would explain alot.