Loctiting Cylinder Studs
 

Am I the only one that thinks it's a bad idea to loctite the cylinder studs without tension?

It seems to me they should be at least slightly loaded to force the threads into their final engagement position prior to letting the loctite cure.

I was planning to slide a pipe over the studs and pre-load with a nut overnight while the loctite cures. Am I going overboard?

My "engine rebuild mentor" (MT912RS) thought this also, and I agreed, so I waited to put the studs in until I was ready to install the heads. I had to be carefull to get the cylinders aligned without the studs in place, but it worked out fine.

I can't think of any feasible engineering reason why tension would make a difference?

-Wayne

How about the engagement of the two threads relative to one another? There is always clearance between the stud and thread, witness the wiggle in an inserted stud, therefore the gaps between mating threads will depend on the tension. A bigger gap will cure and harden with loctite, but you could conceivably break the joint later on, either at assembly or when running the engine hot.

I would like to see the loctite cure with the thread faces loaded against each other.

The engagement of the threads should be pretty snug, If you have "wiggle" something doesnt sound right.Most threads on the stud should be in intimate contact with the threads of the case (casesaver, timesert, etc) any loctite you apply will be displaced to any voids, then cure. Axial play should be nil.

I wont hurt anything to install the studs the way you describe, dont think it has any real benefits though..

http://forums.pelicanparts.com/911-engine-rebuilding-forum/129472-head-studs-new-timeserts.html?highlight=studs

Check out this thread, it's what started me thinking.

It's normal to have some wiggling, particularly if you are using case savers. There are many ways to do things, but to me, this appears to be a non-issue. The Loctite 271 will be enough to keep the studs secure and to keep them from turning when you tighten the head studs...

-Wayne