Repair stripped threads

[Seppi72]

I'm just getting started tearing down an L28E engine to retrieve the F54 block as part of a future stroker motor.

Unfortunately, as I was hoisting the engine to put it on a stand, I discovered that one of the tranny mounting holes was stripped. It's the hole located at one o'clock as you look at the engine from the backside. I don't remember the actual bolt size and pitch, but I should be able to figure that out from other blocks I have laying around.

Does anyone know how I can fix this problem? I presume the best thing is to use a threaded insert like a Helicoil, but where is the best place to get one of those? And how hard is it for an infrequent mechanic to install?

Any advice is appreciated.

[Ed]

A helicoil would be the easiest way to fix it and it's available at any automotive supply store. They are also pretty easy to install. Drill tap, and insert the coil. Another option for you is when you take the block to the machine shop to have it worked, mention the stripped threads. Have them weld the hole then drill and retap. They might also suggest the helicoil. Up to you.

[Inf]

Heli-coils can be found at lots of auto parts stores. I recommend you pay the extra $ and get the genuine heli-coil kit. I've tried the no-name versions before and it led to some complications because of inferior quality.

It isn't that difficult to do yourself, especially if you have some sort of jig to drill a hole perpendicular to the face (i.e. along the same axis as the original hole). I went through this with the exhaust studs on a head rebuilt by some dork out west. He did a pretty poor job installing heli-coil inserts into the stripped out exhaust stud holes. I ended up needing to modify my manifolds slightly with a file so that I could fit them on over the studs.

Just be careful. I learned the hard way to do it right the first time. The aforementioned retard had a helicoil skip a thread so a stud was impossible to put in properly. I couldnt get it out myself because the heli-coil material is too hard. Ended up taking it to a machine shop so they could get it out, as well as do a bunch of other things.... but they forgot to do it! They didn't charge me for that at least. At that point it was too late since I was about to move, so I just made do as best I could. A new motor is probably in order in the near future anyway.

[Bambikiller240]

Same thread/pitch as head bolts.