best thread sealer- head studs.

[MadBill]

A SpeedTalker whose handle I forget mentioned a while back that he drops a ball bearing into each hole before screwing in the stud, to prevent it wedging into the last of the thread. If you're really A-R, you could verify that the stud doesn't thread in as far once the ball's in place.

Madbill. I believe they are referring to an open hole, and thus the need for sealer.

Ah, good point. My focus was diverted by the suggestions re locking materials rather than the predominant strictly sealer alternatives proposed, which would of course be irrelevant for a blind hole.

So, by way of remediation: "Guys, don't play Russian Roulette by randomly dropping ball bearings down open threads leading to who knows where!"

[RD_Racing]

I just finished going through this.. Had to send my motor back to the builder twice because of head stud leaks. After the 2nd time i decided to do it myself.. I read 100's of forums on what others were using and couldnt find anything consistant.. What worked for one person didnt always work for another.. What i found is that its all in the prep. I first chased all the holes with a thread chaser (not a tap).. Then i ran a stainless steel wire brush (from a gun cleaning kit) down the threads a few times and then ran it down again with some brake cleaner and then blew it out good with air. Then i took the studs and cleaned them up on a wire wheel (bench grinder wire wheel).. After everything was totally clean and free of any oils I used 567 (same as the engine builder) and put some on a brush and dabbed it down in the threaded holes and then put some on the studs too before installing them.. Guess what???? NO LEAKS!!! Like I said, I believe its all in the prep work..

[pamotorman]

I just finished going through this.. Had to send my motor back to the builder twice because of head stud leaks. After the 2nd time i decided to do it myself.. I read 100's of forums on what others were using and couldnt find anything consistant.. What worked for one person didnt always work for another.. What i found is that its all in the prep. I first chased all the holes with a thread chaser (not a tap).. Then i ran a stainless steel wire brush (from a gun cleaning kit) down the threads a few times and then ran it down again with some brake cleaner and then blew it out good with air. Then i took the studs and cleaned them up on a wire wheel (bench grinder wire wheel).. After everything was totally clean and free of any oils I used 567 (same as the engine builder) and put some on a brush and dabbed it down in the threaded holes and then put some on the studs too before installing them.. Guess what???? NO LEAKS!!! Like I said, I believe its all in the prep work..

i agree if there is rust in the block threads you can have a leak. what wised me up was used blocks vs new blocks and which one i had leakers.

[dfarr67]

I learned a hard lesson many years ago with head studs,
use high strength loctite red, some in the block some on the stud, screw all the way down then back out half a turn. work quickly to do all studs, then slip a head down into place, let sit overnite, take the head off and clean up the residue. fit head and tension as per normal.
Believe me this works, never had a head gasket issue or any problem doing it this way ever! One man I told, did not believe me and bottomed the studs out with pipe sealant and promptly split the top of the block as the stud moved down into the taper at the top of the thread.
This is why you back them out a half turn.

I thought the lesson you were going to confess to was heating the studs red to remove them after chemically welding them into the block.

[dfarr67]

I just finished going through this.. Had to send my motor back to the builder twice because of head stud leaks. After the 2nd time i decided to do it myself.. I read 100's of forums on what others were using and couldnt find anything consistant.. What worked for one person didnt always work for another.. What i found is that its all in the prep. I first chased all the holes with a thread chaser (not a tap).. Then i ran a stainless steel wire brush (from a gun cleaning kit) down the threads a few times and then ran it down again with some brake cleaner and then blew it out good with air. Then i took the studs and cleaned them up on a wire wheel (bench grinder wire wheel).. After everything was totally clean and free of any oils I used 567 (same as the engine builder) and put some on a brush and dabbed it down in the threaded holes and then put some on the studs too before installing them.. Guess what???? NO LEAKS!!! Like I said, I believe its all in the prep work..

I think where this ends up is- the manufacturer doesn't account for assemblers ignorance. I would agree that there are a lot of opinions out there as far as chemical and most sealers would work with proper cleanliness.

[RD_Racing]

I just finished going through this.. Had to send my motor back to the builder twice because of head stud leaks. After the 2nd time i decided to do it myself.. I read 100's of forums on what others were using and couldnt find anything consistant.. What worked for one person didnt always work for another.. What i found is that its all in the prep. I first chased all the holes with a thread chaser (not a tap).. Then i ran a stainless steel wire brush (from a gun cleaning kit) down the threads a few times and then ran it down again with some brake cleaner and then blew it out good with air. Then i took the studs and cleaned them up on a wire wheel (bench grinder wire wheel).. After everything was totally clean and free of any oils I used 567 (same as the engine builder) and put some on a brush and dabbed it down in the threaded holes and then put some on the studs too before installing them.. Guess what???? NO LEAKS!!! Like I said, I believe its all in the prep work..

I think where this ends up is- the manufacturer doesn't account for assemblers ignorance. I would agree that there are a lot of opinions out there as far as chemical and most sealers would work with proper cleanliness.

I agree... I also think its important to get some sealant down the hole before you install the studs.. By putting it on just the stud threads allot of it gets pealed off as you install the stud and ends up on the surface and by the time the leading thread gets to the bottom, there probably isn't much sealer left on the thread..

[smeg]

I learned a hard lesson many years ago with head studs,
use high strength loctite red, some in the block some on the stud, screw all the way down then back out half a turn. work quickly to do all studs, then slip a head down into place, let sit overnite, take the head off and clean up the residue. fit head and tension as per normal.
Believe me this works, never had a head gasket issue or any problem doing it this way ever! One man I told, did not believe me and bottomed the studs out with pipe sealant and promptly split the top of the block as the stud moved down into the taper at the top of the thread.
This is why you back them out a half turn.

I bet they are easy to remove when you want to or need to. So do you bake the block in a cleaning oven at 700 degree's F to get them to come out?
I'd like to hear more.

Yes some are difficult to get out when they come back for a freshen up but if you have good quality stud drivers it is not a real problem.
On the engines that have through to water holes we use permatex non hardening sealer and that works fine.
I have a 5 man workshop and we do a shit load of engines per year and we don't have any stud or bolt leaks ever, so we keep on doing what works.

[Krooser]

Mostly used permatex non hardening but the last time I had some plumbers liquid teflon sealant and used that... engine is still running so it may have worked.

[ProPower engines]

A SpeedTalker whose handle I forget mentioned a while back that he drops a ball bearing into each hole before screwing in the stud, to prevent it wedging into the last of the thread. If you're really A-R, you could verify that the stud doesn't thread in as far once the ball's in place.

That was CNC blocks carl H.
But that is only for blind holes.Which don't really need sealer.
But an anaerobic sealer from permatex or loctite will do the job. personally I use the loctite stuff on studs that go through to water. Or any other fastener for that matter that is subjected to stress. others get liquid teflon in the brush top bottle.