Head/Manifold studs

[Tim]

I am in the process of rebuilding an A4 I bought on EBay. I have completed the disassembly of the engine. About half of the studs came out when I removed the head, the other half I removed with a cheap stud puller. The stud puller caused a small amount of damage to the center section of the studs (the area with no threads). Do I need to replace the studs with damage to the center, non threaded part of the stud? Also, is there a way to get the nut off of the stud without causing any damage to the stud?

[Al Schober]

Tim,
Some damage to the center part of the studs doesn't matter - just file off any raised metal. The strength of the studs is related to the minor area at the root of the threads. The middle portion of the studs has a lot more metal, and removal of some will have no affect.
As for removing the nuts, some heat and PB Blaster should do the trick. Try putting them into a small soup can with some kerosene and let them soak a few days.

[hanleyclifford]

It would be a good idea to chase each stud hole with a tap to thoroughly clean all foreign matter. When you reinstall the studs use Permatex #2 on the threads. Most of those stud holes lead to the cooling chamber.

[sastanley]

If it was me and I was rebuilding an old engine like this, why would I notreplace all the studs/nuts/bolts?

But then again, it is always easy to spend other people's money!

I would be sure to carefully examine the studs and make sure they have a sufficient amount of threads left..particularly the coarse end which sees corrosion and wear from whatever cooling liquid is flowing thru the block all those years.

[Tim]

All of the studs but one have six threads left on them. One has four threads left. The threads in the block are in very good condition with no signs of corrosion.

[Al Schober]

Tim,
A standard 3/8" nut is 5/16" thick, or 5 threads. I'd replace the stud with 4 threads.

[67c&ccorv]

Without pics...well, you know the saying?