Sealant for cam housing gasket

[Wfolland]

Am getting ready to install my cam housings onto engine head of my 2L. What, if any, sealant would you recommend that I apply to the gasket between housing and head?

[124JOE]

if they are rubber then nothing is needed

[nibbes123]

I always use LOCTITE 515 gasket eliminator on both surfaces with gasket in middle works really well, this is what I use on most of the engine rebuild, great stuff.
Nick

[Wfolland]

Thanks for your suggestions.

[bradartigue]

None. Sealants are a cure for warped parts and lack of surface prep. They end up inside your head (and eventually your oil pump) after you squish the parts together. Nasty stuff.

[toplessexpat]

IMHO Loctite 515 is good for when you don't have a gasket (i.e. as a gasket eliminator), Curil T is a gasket sealer and stays malleable. If you'd like to stay with Loctite, then their Aviation Gasket Sealant is good (albeit slow drying). Loctite Gasket Sealant #2 is good for seals that have vibrations, and sealant #1 for fixed assemblies.

But - if you need a sealant and your gasket doesn't fit right without it, then you've got a problem with the surfaces you're trying to seal, and that needs fixing.

EDIT: Cross posted with Brad.... oops

[majicwrench]

I'm with Brad, if it has a gasket it doesn't need sealer for the most part. Way too many people use way too much sealer on way too many things. Something like you are doing, a flat, machined surface bolting to a flat, machined surface, certainly does not need sealer.

[fiatfactory]

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[nibbes123]

Glad to hear someone else has used the loctite 515 with good results.

Nick

[toplessexpat]

I'd read the OP as saying he's using a gasket plus a sealant....

Agree if no gasket then using sealants like 515 is handy...... Although I know a guy with virtually no gaskets in the entire engine, or sealants, and a lot of patience for hand lapping....

[TimpanogosSlim]

A good friend of mine with a degree in mechanical engineering has been building engines at a machine shop full time for about 12 years now.

I've visited his work area numerous times. They mostly attract chevy, pontiac, olds, ford, and for some reason jeep engines but he's done some of everything over the years.

The shop he works at warranties every engine he builds. If it leaks he has to fix it for free.

And i can tell you that nearly every major gasket he installs goes on with one kind of sealant or other.

Preferably the surfaces should be totally clean - wipe down with acetone or brake kleen on a rag.

On things like cam boxes, particularly those that have been machined to return them to flat, I've seen him use black RTV out of a caulking gun on both sides of the gasket.

If you know the surfaces are likely not really well matched, it's best to place the part but not torque down the hardware more than finger tight until you've given the RTV time to cure.

He is of the opinion that all major brand RTV products are basically just as effective as any other provided proper surface prep and usage. Many will disagree, but not many have assembled as many rebuilt engines as he has.

When i was building my 1.6TD, he seemed to fully approve of my use of permatex hi-tack on stuff like the carriers for the main seals. fwiw he insists that the main seal carriers MUST be glued on, and to hell with whatever the service manual says.

Permatex copper spray-a-gasket imho works great for adding a little assurance to paper gaskets. If only my can of it didn't clog every 5 seconds.

I hear good things about Hylomar.

He even still uses Indian Head Shellac for . . . something. he said there's something that it's the only good sealant for. I forget what.

Most freeze plugs get some red loctite. Certain ford blocks have to have the freeze plugs jb-welded in for some fool reason that they haven't found a better resolution for -- they're using the factory specified size, the holes haven't been messed with, maybe there isn't a standard freeze plug that happens to be 1/64" larger diameter?

So, here's my advice:

If the gaskets are paper or other fiber composite, or cork, RTV that stuff up. A light application will do. If the surfaces aren't factory-perfect, maybe a heavier application. hylomar or hi-tack works good too.

If it is rubber, silicone, neoprene, etc, you can probably get away with just the gasket provided that there is a spacer to prevent the gasket from being excessively crushed (I understand that this is NOT the case with fiat cam boxes?), and in any case torque specs should be followed carefully. I wouldn't use RTV on a rubber gasket that may squish and slide. But i might use hi-tack or hylomar.

For the cam box gasket, I might use a thin coating spray-a-gasket or hylomar spray or hi-tack.

Here's my basic logic:

Manuals often do not specify whether a gasket should or shouldn't have a sealant applied. When in doubt, i evaluate the surfaces and decide on a light or heavy application. For example, the oil filter flange on my 1.6D block had been glued on with some kind of space age lord knows what - and had still clearly been leaking. I had to remove it from the block with a strike from a mallet. The adhesive residue on the block resisted 3 passes through the block washer at the machine shop and several passes with dremel wire wheels. It also resisted acetone and xylene. I used a razor to remove all i could, and there were still squidgy little specs of it on the block.

So when i reassembled, both surfaces were cleaned again with acetone. I applied a thin bead of permatex ultra copper to the flange face, stuck on the gasket, applied a thin bead of ultra copper to the block side of the gasket, and placed it on the block with the bolts lightly turned. Then after an hour i torqued them down.

My filter flange does not leak, and my oil pressure sender in the flange buries the needle on my 80psi pressure gauge.

Sometimes the manual will specify that a gasket should NOT have sealer. In these cases, I consult the experts and find out how much success they have had following the factory instructions.

Sometimes, like with old VW diesel engines, the bentley manual and the factory shop guide both say NO sealant on the head gasket, and it turns out that this is a shameful lie because there is clear evidence that the original gasket had a thin coating of a hylomar-like substance on both sides when installed, and your new gasket has no such coating.

And other times, like the oil pump on a fiat twin cam, when they say no sealant they mean it and they have good reasons. Not that i understand those reasons, but the guys with experience stand by it.

If the manual says to use sealant and the guy who sold you the gasket says that with their gasket you won't need it, the guy who sold you the fancy gasket is talking out of his butt. Even if you're going from paper or cork to rubber. Even if it's rubber, if it's a seal that won't be broken again except in case of catastrophe that would require a replacement gasket anyway, yes i absolutely break out the sealants. Oil pans are a good example here. The last engine i built has a steel windage tray with a molded rubber gasket that has neat little sealing blades on it, and i put half a tube of permatex ultra-black on it because if i drop that pan something truly horrible has happened, and until then i'd prefer not to leak.

But my similar rubber and bladed (and spaced to prevent excess squishage) valve cover gasket on the same engine, I'm going to have to take that off again and re-torque the head bolts in a thousand miles. And i will have to take it off again every time i adjust timing or change the timing belt because it's an old mechanical diesel. So i will reserve judgement on whether to use sealant until there is an obvious problem.

If a seal is holding back pressure, it gets sealant.

If a seal is the proverbial toad at the center of the universe, unless there is a damn good reason not to, it'll get sealant. Rear main is a good example here - though pulling an engine from an old spider is surprisingly easy.

At this point i sound like I'm rambling. So, two bits on cam box gaskets:

I've heard that the valves should be adjusted every time the cam box is removed and replaced, because the distance between the cam box and the head will vary. This sounds to me like horrid design and something that could be resolved with studs and carefully selected spacers.

Plenty of oil passes near by and the exhaust cam box is a common leak on these engines.

In this position i would use the best gasket i could lay hands on, and i would use a thin application of a high quality sealant regardless of how good the surfaces are. Because i never want to have to take those pieces apart again.

[majicwrench]

The above post is a perfect example of what I posted earlier:

Way too many people use way too much sealer on way too many things.

[131]

The above post is a perfect example of what I posted earlier:

Way too many people use way too much sealer on way too many things.

X2.

[TimpanogosSlim]

The above post is a perfect example of what I posted earlier:

Way too many people use way too much sealer on way too many things.

And the downside is?