I'm installing heads on a 454 this weekend, and I plan to use Permatex "Hylomar" spray as a gasket dressing. Although the stuff is recommended for this use, instuctions on the can are minimal. If anyone has used this product for steel shim head gaskets, I'd sure appreciate sharing some wisdom. One coat? Several coats? Any tips would be great.

It works excellent on shim gaskets. Put a couple of even light coats on & let the solvents dry for about 10 or 15 minutes. This is VERY important.
After the solvents dry you basicly have all day to install the gaskets.
There are other things that will work quite well but Hylomar is real good stuff for shim gaskets & also head bolts that go into water.

What is this stuff b/c all I have used is both Copper-Cote spray and dauber??

I've even used good old Indianhead shellac gasket cement in the shoe dauber bottle as well as aluminum spray paint.

Thanks in advance.

pdq67

The version I'm using is put out by Permatex (Item # 81998)and comes in a 5 oz spray can. It is specifically designed to seal flanges and head gaskets, and is supposed to be good to 600 degrees F. I called all over the place to find it (SF Bay Area), and my local parts store finally had to order it for me.

pdq,
It was originaly used by Rolls Royce on their aircraft engines. It is a non hardening sealant & a very lightweight threadlocker.
Sold by Permatex in spray & by Valco in spray & in a brush can. We use the Valco spray on head bolts & intake bolts etc. & uncoated shim gaskets.
Used to use aluminium paint on the gaskets also & never had a problem with it but this stuff seems to do a better job & it never hardens.

Here's a blurb from Valco:
GASKET MAKER AND THREAD SEALANT
HylomarŽ is a polyester polyol-based compound that turns from a gel into flexible putty within minutes of application. Originally developed by where Rolls Royce, where it performed under the most stringent aerospace tolerances, Hylomar brings superior qualities to automotive applications. Its non-hardening formula maintains seal integrity even when subjected to thermal distortion and vibration.

Hylomar is impervious to oil, gasoline, glycol and other engine fluids. Hylomar is oxygen-sensor safe, seals gaps .01" or less, and performs at constant temperatures up to 600°F. with Hylomar, components are assembled, reused and reassembled with ease.


Steve,
If you need any more email me. I get the Valco & it comes in a bigger can than the Permatex & as I recall it's cheaper smile.gif

NEET!!!

Thanks guy's, I will look for the stuff..

pdq67

Digging up an old post........

I am using GM steel shim head gaskets for my 454. Is Hylomar still they way to go?

Used the Copper Coat on my Mr Gasket shims last Oct. with no problem. Sprayed a couple light coats both sides and let dry.

And aluminum spray paint too.

pdq67

I use the Hylomar for various applications including steel shim head gaskets. It works EXTREMELY well. I've also used Copper Kote and aluminum paint and they both work OK, too.

I prefer Hylomar because it's very versatile and tough but it is MUCH more expensive when compared to more standard sealing agents. Because of that, it's also harder to find locally.

Randy