Gummed up threads on cylinder head....

[KCLOST]

Last night I pulled the cylinder cover water jackets for inspection....<br /><br />Most all the bolts came out easily, but a few were tight and after removal contained some aluminum on the bolt threads (only a few threads contained aluminum)... Obviously a result of seizure.. So now a have a few holes that have "slightly stripped" threads.<br />I'm planning on tapping the holes with the current thread size to clean out and try that. I think it will work due to the low torque required for the water jackets..<br /><br />But I wanted you're thoughts, and also any recommended anti-sieze that will work for a steel bolt going into aluminum...<br /><br />Motor below...

 

[Paul Moir]

Re: Gummed up threads on cylinder head....

You want to use a zinc and/or graphite based anti-seize, rather than a primarily copper based one which will not help at all. Common automotive exhaust system type anti-seize is copper based.<br /><br />Permatex makes this sort which seems alright.<br /><br />Speaking of goo, your semi-stripped screw holes might be just the place to use one of those anerobic thread repair glues.

 

[KCLOST]

Re: Gummed up threads on cylinder head....

That's what I just purchased, except it's in a stick form, kind of like a soft crayon consistancy... It's not permatex, but it has the same description and temp. range (for aluminum heads)...<br /><br /><br />I also found some thread restorer, 2-part compound made by Permatex for $10. Made for engine block repair... Going to try it also...

 

[emckelvy]

Re: Gummed up threads on cylinder head....

Permatex #3 aviation gasket dressing is non-hardening, and won't cause any issues with electrolysis.<br /><br />It effectively seals the bolts and keeps any salt or other deposits out of the threads. I use it for water jacket and outer exhaust cover bolts all the time, and it works great.<br /><br />Re: your threads issue, if they are too sloppy to hold torque after cleaning them out with a tap, install a Heli-Coil. You can get the kits at most hardware & automotive stores. The thread will be stronger than new, once the insert is installed.<br /><br />HTH.......ed

 

[KCLOST]

Re: Gummed up threads on cylinder head....

Ed, the Heli-coil is out of the question. I believe drilling out a bigger hole that will be needed for the coil, will cut into the combustion chamber.<br /><br />I tried the Permatex thread repair last night and it worked great...<br />I think I'm ok.