Steel shim head gasket sealant

[user-17438]

Hylomar.. because Rolls Royce couldn't figure out how I make an engine that didn't leak. This stuff works..

[cjperformance]

Hylomar.. because Rolls Royce couldn't figure out how I make an engine that didn't leak. This stuff works..

[Krooser]

https://www.autozone.com/sealants-glues ... et-shellac

[PackardV8]

Re: Hylomar; didn't we have a member here from Dakota Parts Warehouse who was the Ferrea valves and Hylomar distributor? Anyone buying Hylomar from them?

[rocketracer380]

Hylomar works mint I've used it on copper gasket with great success no leaks ever expensive tho

[tenxal]

Re: Hylomar; didn't we have a member here from Dakota Parts Warehouse who was the Ferrea valves and Hylomar distributor? Anyone buying Hylomar from them?

Jack, the ebay link I referenced in my earlier post is him. Brian @ Dakota Parts Warehouse in Rapid City, S.D.

[novadude]

While we are on the topic, how flat does the deck need to be for a steel shim? Can you get away with running these on an undecked block if the block is reasonably flat? What are the limits?

[F-BIRD'88]

It is the flatness of the head that is more critical.
Never used a sealant on sbc and bbc steel shim head gaskets in 40++ years. Have instructed others too same. No failures even with nitrous and supercharging. Waste of money.

[rfoll]

My concern about sealing mostly comes from the usage of a steel shim on a 400 block. Steel shim gaskets fore this bore size are very rare, and getting them to seal is probably the reason. I'm not worried about combustion seal, but I have had coolant seepage on these blocks in the past. The gaskets don't have steam holes, but I will drill the bottom 3. The holes on the upper side of the block have been plugged.

[Newold1]

Rfoll, maybe my eyes are really getting bad or thats not the gasket type in question but those pics on the Speedway motors listing appear not be a steel shim gasket but some type of composition gasket with a definite separate compressible fire ring around the bore opening. If so then steel shim seems to be a misnomer. In any event if those are indeed composition head gaskets at $10 a pair, just the pricing alone would make be a bit suspect of the quality of the gasket set.

In any event I have found over my history that early on when surface decking, surfacing and head gasket construction was not as refined as it can be today, using head gasket sealants as a crutch for some pretty sloppy decks and finishes that head gasket sealants were just about a must. I can say that in the last 30 + years I have never used head gasket sealants not because they are a problem necessarily when used but because I as well as many engine builders today realize that properly squared and surface deck RA's with good head fasteners properly torqued and using quality head gaskets that sealant is not needed. No redo or failures in my experiences. My thoughts, the "right surfaces at the right torque with quality head gaskets make leaks a thing of the past."

[Truckedup]

While we are on the topic, how flat does the deck need to be for a steel shim? Can you get away with running these on an undecked block if the block is reasonably flat? What are the limits?

How flat were the blocks GM machined? They often have a rough finish, I think they were broached, not milled...I used silver paint on GM and Mopar in the past...Last one I did got the copper spray...

[engineguyBill]

When installing thin, steel shim head gaskets, I have used high temperature silver paint that is made for barbecue grills (both spray and brush on) for 50+ years with no issues/failures. Installation procedures are of utmost importance, i.e. gasket surfaces must be clean and dry; head gasket threads and threaded holes in block must be clean (I use thread chasers, NOT tap and die); coat head bolt threads with very light coat of thread sealer; coat the gaskets with silver paint and install heads while the paint is slightly tacky; torque the heads bolts in recommended sequence - in at least three steps.

[PackardV8]

When installing thin, steel shim head gaskets, I have used high temperature silver paint that is made for barbecue grills (both spray and brush on) for 50+ years with no issues/failures. Installation procedures are of utmost importance, i.e. gasket surfaces must be clean and dry; head gasket threads and threaded holes in block must be clean (I use thread chasers, NOT tap and die); coat head bolt threads with very light coat of thread sealer; coat the gaskets with silver paint and install heads while the paint is slightly tacky; torque the heads bolts in recommended sequence - in at least three steps.

Bill, agree with all the above but one, "(I use thread chasers, NOT tap and die)" in fifty years of chasing threads in blocks with standard taps, I've never had an issue I could trace to same.

FWIW, I do use bottoming taps on any block which has been aggressively decked beyond just cleanup or which will use heads milled more than cleanup. There's a lot of crud hiding in the bottom of bolt holes, even those baked/blasted/pressure-washed.

On the crusty/rusty stuff we build, it's sometimes necessary to chase head bolt threads with a die and to use a washer under the head. On the shorter bolts, sometimes there's a later more current production bolt which will interchange, but I still haven't found anything as long as the Packard V8 rocker stand head bolts.

[rfoll]

The gaskets are in hand, and are in fact shims. The deck is freshly machined, the heads are nearly new and very heavy. First time I have heard if putting it together with the paint wet. Interesting thought.

[roc]

The gaskets are in hand, and are in fact shims. The deck is freshly machined, the heads are nearly new and very heavy. First time I have heard if putting it together with the paint wet. Interesting thought.

Good deal, do they look like the ones in the picture? https://www.speedwaymotors.com/Speedway ... 39728.html

The ones pictured do look like composite ones.