I stripped a hole on my flexplate

[HighHooder]

Do I have to replace it?  I was thinking about drill and tapping the hole but then I thought about balance.  Do I do have to do both sides (3 & 9 o'clock)?  Or am I just over thinking the problem?

[volkenstein]

Highhooder,
                   With the TEENSY difference using Helicoil would make I'd do it. Re-thread back to original size, tiny amount of hi-strength
Loctite on the insert and away you go. The plate is balanced and don't forget the Torque Converter absorbs a hell of a lot of imbalanace anyway. If you want it balanced, balance it as a seperate unit on it's own.

If I was going with a whole built up 1776 or bigger new engine, yeah, I'd throw it all at a balance shop.


HTH
Volkenstein

[68autobug]

Hi
Yes, the flexplate has to be perfectly balanced..
You could tap ALL the threads, maybe not in metric, if You can use the same or slightly larger  sized hole..
At one time, I used 4 allen headed hi tensile bolts on My flexplate, and I cut and ground down the ends so they were all the same... identical.. 6mm x 12mm long
[the heads were about 7-8mm long]  You could also use a multi splined bolt.. [allen type]

I believe the best solution would be to retap all 4 holes to the same thread and use identical bolts.  I believe that would fix the problem..
   Don't use any thread locker [loctite etc] as I did once, and one of the nut pieces came off the back of the flexplate..  as they are only sweated on...  I still have that flexplate... hanging on the wall in My shed.. lol..  I should get it brazed back on and then balanced..
maybe someone who balances things on motor cycle clutches etc.. should be able to balance them by adding weights... [I don't know what they use to balance clutches etc??}

so, also be careful when tapping the nut threads..  You don't want a nut coming loose..
The flexplates I have, some have holes drilled on one side and weights added on the other side, but they are ALL different..   so they have been perfectly balanced.. individually..
You wouldn't think there would be much difference in the weight of the flexplate as apart from the nut pieces, which would seem to be identical, there is only the center hub part...

so, 5/16 inch bolt threads may be the closest to the original 6mm threads..
about 7/16" long or very slightly longer..
now the 6mm allen headed bolts are about 12mm round [diameter]
I don't think You can go much larger before it hits the gearbox housing.. so You would need to think about that.. If they were too big and hit the gearbox sides then You could grind the top  down slightly..  again, just making sure that they are all identical..

best of Luck

Lee in Australia

[68autobug]

Hi Sean
You answered while I was measuring My bolts.. lol
as I said all the flexplates I've seen are all different with holes and small weights to balance them so it seems they must be perfectly balanced.. 
I just know that unbalanced the flexplate can vibrate and loosen the rivets in the hub..
and re punching the rivets doesn't fix the problem... maybe new rivets??  mine was welded in 4 spots and still broke away.
its now welded all the way round but I haven't re used that flexplate....
My Son has a welding ticket too..  lol
I know You have more experience with torque converters etc.. so maybe the flex plates don't need to be "perfect"..   lol
OK on the helicoil also.. something I hadn't thought of..  [still thinking perfect.. lol]

cheers

LEE

[HighHooder]

Thanks for the replies! 

Here is a complimentary picture

[volkenstein]

Highhooder,
                   That's a move not often seen, single IDF. So, knit & macrame...I spy a 009....so where is the vac source for the control valve and how is it actuated at the carb? Via the distributor vac port they supply? Give it up ....

A guy - 73Kafer (IIRC) on www.Thesamba.com has a similar setup. Might pay to pick his brains.


HTH
Volkenstein

[HighHooder]

;)here is the source for the big vacuum line.  I tee'd the two ports and ran a single hose to the control valve.  The smaller line is just a vacuum port off the carb. 



The

[68autobug]

Hi
I can't see why that won't work.

Lee

[HighHooder]

It actually works well, Bugsly @ Mouse Meat said that it would have worked fine even if I had tapped just the one side.

She should be up and running later today (fingers crossed) and then I get to break in the new cam... Scat C35.