flexplate bolts and reinforcing ring needed

dooghssr

I have search for the past 3 hours and called Summit and ARP with now luck. I am putting a TF-727 behind an AMC 401 and need to know the flexplate bolt size and where I can find the reinforcing ring that goes between the flexplate and bolts. Any info would be appreciated.

ironman_gq

bolt size is probably the same as the flywheel bolts. might even be the same as chevy or ford. take a tap set and find the one that you can thread in by hand.

dooghssr

I have the old flywheel bolts so I know the threads just need the length. It is either .680 or 1/2 long. I think the reinforcing plate is going to be the bigger issue.

AMX69PHATTY

Scroll down in this thread about halfway and there's a picture of a pile of misc. parts for sale with some flexplate mounting bolt rings in the upper left corner. Looks like there is more than one type there, not sure which type you're looking for, seller is 71SC360 in New York I believe.

http://theamcforum.com/forum/forum_posts.asp?TID=7089

dooghssr

I see 3 of them. I will PM him. Thanks

RacerAMX

Use the 1/2 inch length bolts. Any longer and the bolts might hit the block when they come out the backside of the crank flange.

dooghssr

I ordered the reinforcing ring from 4wd.com and only 4 of the 6 holes line up. The flexplate is good, but not the ring. Not sure where to go from here.

AMX69PHATTY

The Flexplate / Crank / Boltring Pattern aligns only in 1 position. Sure it is clocked correctly ? The 4 Torque Converter to Flexplate Bolts are the same way. All 4 line up in only one position. Best to determine where that is and mark parts before mating engine to trans. If misaligned, converter will not rotate 360 deg with trans bolted to block. The tapped pads on the converter with hit the flexplate balance weight. Both of these is because the Flexplate is part of the engine external balance. :idea:

dooghssr

I rotated the ring a million times. It just doesn't match no matter what. I made sure the flexplate did and the torque converter to the flexplate, but the reinforcing ring won't mate at all. Not sure what to do from here. About to uni-bit the other 2 holes and make it work. I wish I could say too much beer, but thats not the case. I will try and take a picture and post it.

AMX69PHATTY

Was it flipped over and tried using the other side ? iirc only one hole is "off", but not sure. :-|

dooghssr

I tried everything. 2 of the holes are about half off. Is this ring really needed?

AMX69PHATTY

Have always used one.
Guess it prevents the bolt heads from digging into the flexplate.
Would imagine it helps to evenly distribute the clamping force.
Last thing wanted is a craked flexplate.
Was 71SC360 able to sell one from the "pile of parts" picture ?
Wonder if they're still availble from a Jeep / Chrysler Dealer ?
One for the TH400 Flexplate may be different.
Don't have the part number for those.
This is info for the TF727 and Borg Warner trans Flexplates.

Try Part # J3152968 or # J3214094 at a local Jeep Chryco Dealer maybe ?

What Transmission is it ?

Zoner

The bolts are 1/2" fine thread place bolts. Threaded section is .550 long The ring is stamped out of .050 steel. Outside diameter = 4.750. Bolt hole diameter is 0.525. It's probably something one could fabricate in a pinch. I'd agree with Phat, the ring is there to distribute stresses from the bolt heads. There's a *lot* of energy being transferred from the crankshaft to a relatively thin metal plate there.

dooghssr

The trans is a 727. I got the bolts from the dealer. I guess I could order the ring from them too. I am just afraid it will be the same one. Could I just hone out the 2 holes that don't match up. About a 1/4" on both.

dooghssr

I got it. Lined up the 4 holes and marked the other 2. Used a dremel to widen out the one side of the hole. Fits well now. What is weird I could get 5 holes to also line up, but the 6th was off by over half a hole. This work now. Going to go install now.

Zoner

What style crankshaft are you trying to bolt to? The flexplate has a balance weight on it that is placed to counteract dynamic vibration that the internal rotating masses in the engine will produce. It's supposed to bolt to the crankshaft in one position only, and that's the reason for the offset hole.

dooghssr

Got the flexplate and reinforcing ring mounted. I think I am good to go. Just need to get the Lokar shifter positioned before the trans goes up. Have the flexplate and torque converter lined up and marked, so the rest should be straight forward.