Chevy Nova Forum banner

1 - 20 of 32 Posts

·
Banned
Joined
·
435 Posts
Discussion Starter #1
What do you use as a thread sealant on headbolts?

Not long ago I had some work done on some BBC heads. The machinist...who was very experienced...used RTV silicone to seal the threads which kind of surprised me because it's not what ARP reccomended. However, I take his experience and advice seriously because he's assembled a LOT of engines and guarantees everything he does.

Anyway, I'd enjoy hearing what others use, especially if you've done it yourself and speak from experience. If I'm not mistaken, only a few of the BBC headbolts are actually in the water jacket.

Thanks....
 

·
Premium Member
Joined
·
13,309 Posts
Permatex #2 non harding gasket maker, or Permatex RTV Ultra black...

I like the #2 non hardening.. its stays pliable and ease of cleanup.... I also prefer it because is will dissolve and breaks up in to very small pieces.. to me this is important as you can never get it all removed from the block.. so some always floats around... and the small the particial.. the better chance it will pass through the radiator with out plugging a tube
 

·
Registered
Joined
·
3,895 Posts
Ultra Black here:yes:....SEVERAL TIMES on numerous builds, rebuilds, head swaps and R & R's, etc..... Never had a problem.:no:
 

·
Registered
Joined
·
1,167 Posts
I bought a small little bottle of the permatex anti seize thread stuff, applied by a brush, just curiuos if anyone's used that stuff for head bolts? and how well it worked?
 

·
Registered
Joined
·
3,895 Posts
I bought a small little bottle of the permatex anti seize thread stuff, applied by a brush, just curiuos if anyone's used that stuff for head bolts? and how well it worked?
That's anti-seize compound, not thread sealant. It might work....It might not...

Hint: Silicone is also known to be a good anti-seize compound for low temp stuff...IE: water pump bolts (typically go into water as well), water neck bolts, intake bolts (exposed to lifter valley and crank case pressure and are in many cases, steel bolts going into aluminum heads), etc...
 

·
Registered
Joined
·
1,167 Posts
That's anti-seize compound, not thread sealant. It might work....It might not...

Hint: Silicone is also known to be a good anti-seize compound for low temp stuff...IE: water pump bolts (typically go into water as well), water neck bolts, intake bolts (exposed to lifter valley and crank case pressure and are in many cases, steel bolts going into aluminum heads), etc...
I got dragged into the cool little bottle it came in... but i guess now i have tons of anti-seize for spark plugs, thought i read somewhere antiseize on headbolts... o well good thing i have the black rtv high temp silicon stuff :) thanks :)
 

·
Registered
Joined
·
3,849 Posts
I got dragged into the cool little bottle it came in... but i guess now i have tons of anti-seize for spark plugs, thought i read somewhere antiseize on headbolts... o well good thing i have the black rtv high temp silicon stuff :) thanks :)
Oh, and for anti seize, I really like (and hate) the napa stuff in the gray can. Love it cause it works great, high temp included. Hate it cause Im silver the whole day after using it LOL The stuff is like air for me, gets on everything and doesnt come off. Great for the long suspension bolts too, where they contact the tubes, not for the threads..JR
 

·
Banned
Joined
·
435 Posts
Discussion Starter #13
Pluggin' around

As always, the comments are a great help. Now, I can see that RTV is used by a lot of people who know what they're doing. Thanks.

However, this remark caught me by surprise:

...I have tons of anti-seize for spark plugs, thought i read somewhere antiseize on headbolts... o well good thing i have the black rtv high temp silicon stuff :) thanks :)
I was told long ago never to use anti-seize on spark plugs. Spark plugs transfer heat from the combustion chamber to the cylinder heads. The problem with anti-seize is that it acts like insulation and interferes with their ability to do so. Because a spark plug's heat range is so important you don't want to use anything that affects the plug's ability to dissipate heat.

Anyway...that's what I was told. Makes sense to me but feel free to add your comments.
 

·
Registered
Joined
·
6,437 Posts
Head Bolt Sealers

Permatex #2 non-hardening as has already been mentioned is old school, but, I've never heard of anybody having problems with it.
I'd be cautious with using RTVs. A lot of them are great. A lot of them swell and get gummy in hydrocarbons, gas and oils.
Bottom line is you're problably OK cause the machine shop has a good track record with what they use.
A few of the follow ups threw up some red flags.
Anti-seize products usually have metal in them, that's why they are silver and shinny. I know you're sealing the water jackets for the most part, but, I wouldn't put metal powder suspended in magic juice anywhere inside my engine.
I think it's also important to consider torque vs tension properties of any sealant that also lubricates (the anti-seize and the sealant with teflon product) When you tighten a head you do it to a torque specification. That does two things, it provides the proper clamping pressure between the head and block, and, it stretches the head bolts the right amount to maintain that clamping pressure. Think of the bolts as very heavy springs. If you over lubricate the bolt threads with some super slippery stuff you end up turning the bolt further into the threads with the same spec torque. This puts more than the recommended clamp on the head/block but worse, it can overstretch the bolts. The bolts may not break, just yield a little causing lose of clamp and head gasket failure.
 

·
Registered
Joined
·
6,437 Posts
As always, the comments are a great help. Now, I can see that RTV is used by a lot of people who know what they're doing. Thanks.

However, this remark caught me by surprise:



I was told long ago never to use anti-seize on spark plugs. Spark plugs transfer heat from the combustion chamber to the cylinder heads. The problem with anti-seize is that it acts like insulation and interferes with their ability to do so. Because a spark plug's heat range is so important you don't want to use anything that affects the plug's ability to dissipate heat.

Anyway...that's what I was told. Makes sense to me but feel free to add your comments.
Hi,
Don't know where you heard that but that's not entirely right. As I described in my previous comments, anti-seize products have metal in them, tin, aluminum, copper, combinations, depends on the brand. Some used to have lead I think. They are better at transfering heat and electricity for that matter better than anything else mentioned so far. I still won't put it in my engine.
(Just a note. I worked five years for Loctite in the early 70s, just out of school, as an Application Engineer. Fancy title for a guy that recommends the right juice for the job.)
 

·
Premium Member
Joined
·
13,309 Posts
as for Antisize.. I prefer Nickel based... in wet locations.. dry.. and I do me arid dry.. I take a tip from Boeing.... (dont laugh) dip the bolts in Maalox or mylanta and torque immediately :D
 

·
Banned
Joined
·
435 Posts
Discussion Starter #17
... in wet locations... I take a tip from Boeing.... (dont laugh) dip the bolts in Maalox or mylanta and torque immediately :D
Veno:

You KNOW that comment is going to get more responses than anything anyone has said.

BTW, does Maalox make what's s'posed to happen naturally come sooner or later?
Sometimes, I could use the help.

Never mind...forget I said that!
 

·
Registered
Joined
·
6,437 Posts
Maalox

as for Antisize.. I prefer Nickel based... in wet locations.. dry.. and I do me arid dry.. I take a tip from Boeing.... (dont laugh) dip the bolts in Maalox or mylanta and torque immediately :D
Never heard that one. Is that why JT9D head gaskets don't leak. Real old school, for thread locking, if you worked for the Union Pacific, would be to dip the threads of the rail plate bolts into a pee bucket.
 

·
Registered
Joined
·
3,895 Posts
I was told long ago never to use anti-seize on spark plugs. Spark plugs transfer heat from the combustion chamber to the cylinder heads. The problem with anti-seize is that it acts like insulation and interferes with their ability to do so. Because a spark plug's heat range is so important you don't want to use anything that affects the plug's ability to dissipate heat.

Anyway...that's what I was told. Makes sense to me but feel free to add your comments.
The first time you take out a spark plug and the threads come out of the head with it your opinion will likely change.:yes::D
 

·
Banned
Joined
·
435 Posts
Discussion Starter #20
Real old school, for thread locking, if you worked for the Union Pacific, would be to dip the threads of the rail plate bolts into a pee bucket.
Great answer...but why do I have the feeling parts of this thread will soon be edited out?

KDee, in response to your earlier question about the source of information on the thread sealant /spark plug issue his name was Bill Fisher and he authored several publications on engines and engine building. But all of that was several years ago and perhaps it has all changed. I don't know.

Anyway, that's the source of the information.
 
1 - 20 of 32 Posts
Top