legacycentral bbs

I miss-read the Haynes manual when I was removing the timing belt and started loosen the tension pulley instead of the tensioner. I backed it out few turns before determining that was a bad idea. I switched over the endwrench removal method. After the belt was off I removed the tensioner pulley to get the water pump off. However, when I went to put the tension pulley back on, the block mounts treads are stripped. I've reviewed some history on this site:

Engine Noises then Abrubtly dead
http://bbs.legacycentral.org/viewtopic. ... t=helicoil

The Story of Bearings in My Timing Belt Cover
http://bbs.legacycentral.org/viewtopic. ... ioner+bolt

I was able to get a longer m10x1.25x75 at ace which is only an 8.8 grade bolt to test if a longer higher grade bolt would work. But it will not go past the problem spot without messing up the treads more. I can get a m10x1.25 tap and take it down to the bottom or I can get a helicoil kit at pepboys for $45 plus the drill bit for $6 and a 90degree drill convert for $31.

So am I better off installing a helicoil on the top of the hole where the original bolts treads or go deeper with a non-stock 10.9 grade m10x1.25x70mm bolt after re-tapping it using no helicoil? The stock bolt is 55 or 60mm long... I think.

Or can I get around this problem by using a phase II tensioner and mounting bracket? That tensioner looks like it would be less stressful on that pulley block mounting point.

Timing belt tensioner- new part number?
http://bbs.legacycentral.org/viewtopic. ... ioner+bolt

It's a 93 turbo ss auto with 156K.

how much threads are there in the block that arent stripped? if there is a good amount I'd probably try and chase the messed up threads first and see if you can get the right torque and if not then do a helicoil.

For the thread length of the bolt, about 2/3rds was gone and the last 1/3rd was messed up. I could not go very deep with the longer bolt without re-stripping at just 18ft-lb. I ended up using a helicoil a few nights ago. I set the coil with a small amount of loctite red and let it dry over night. Last night I reassembled it with no problems torquing correctly at 29ft-lb. The hardest thing about the helicoil install was getting the 90degree drill attachment straight. Even with the threads gone out of the front on the hole, making a nice pilot hole, I was off angle by about a 1/16" at the end.

I way over thought this helicoil install. I thought I would have to stack the coils to match the bolt thread and was worry about the lateral force on the tension pulley. But after thinking about it and reading on the web, one coil is all you need because most of the bolt pressure is on the first three threads. Think about it like a nut with less threads. It holds large torque without a problem.

For anyone else that has to do this... When you set the coil make sure it is not flush with the top but about two thread deeper. When you look at the bolt coming out of the pulley collar you will see why.

Here is some info that I found:
http://www.hotrodders.com/forum/will-ch ... 510-3.html
http://www.emhart.com/products/helicoil.asp