Head Studs, Etc.

[Walter Pearson]

My head stud threads are in fairly good condition, but there is some mottled, surface corrosion on the shank portion. At what point are new studs warranted? The diameter might be 0.010 under in the worst areas.

Some suggest anti-sieze compound on the shanks when reassembling. Is there any problem in doing this? I would probably prefer to put a thin coating of anti-sieze in the corresponding cylinder head holes instead so any excess would be forced up and not skived off at the gasket interface.

There are a couple stud thread locations in the block (near #4) where I cannot get a cleaning wire through. It feels solid and not like crud buildup. Can I assume there are blind holes there?

Your original newletter on head removal and reinstall calls for Permatex to seal the lower stud threads and the excess spread for the gasketed surface. Loctite Red has been mentioned in your recent responses. Any reason for the change?

[Don Moyer]

Walter,

Here are the answers to your questions:

1) At what point are new studs warranted?

We usually only replace studs if the threads on either end are defective.

2) Can I assume there are blind holes there (in certain stud holes)?

The only cylinder head stud hole that does not enter the water jacket is the one in the center of the head on the reversing gear end of the engine. This is the stud hole that one of the coil bracket bolts intercepts.

3) Loctite Red has been mentioned in your recent responses. Is there any reason for the change?

We find that ruby colored Loctite (called "stud locker") adds a bit of strength to the area in cases where there may be some concern over the integrity of the threads, and - more importantly - it seems to be more reliable in preventing water leaks from around the studs.

Regards,

Don