The heads for this motor project were done years ago and over time some very, very light pitting has occurred on the head intake mounting surface. I typically don't use any sealant on intake gaskets, but in this case I was thinking about a very light ("skim") coat of high temp RTV silicone (orange). I thought about the spray copper sealant, but the directions say to spray both surfaces and since the heads are already on the block, that would be messy and/or require alot of masking. Any thoughts?

Thanks,

Rono

  Ron Lane,  Meridian, ID

My professional mechanic friend advised me to use black permatex on both sides of the intake gaskets, particularly around the coolant passages... and plan on replacing the gaskets if I ever pull the manifold.

This has worked fine so far...

I wouldn't use RTV or silicones not good for intakes [fuel] . I use permatex no.3 however not sure if it makes much diff' , the RTV type might be ok around the coolant holes tho', better than nothing . There will be gasket goos that are fuel resistant.



"Came too close to dying to stop living now!"

I wouldn't use RTV or silicones not good for intakes [fuel] . I use permatex no.3 however not sure if it makes much diff' , the RTV type might be ok around the coolant holes tho', better than nothing . There will be gasket goos that are fuel resistant.



"Came too close to dying to stop living now!"

Having R & R'ed many intakes on 'Y's thru the years I have never used any sealant on the intake gaskets but have had the displeasure of removing the sealant that others have when I had to work on the motors after.

Good clean surfaces are the key.

Good Luck

312T85Bird

What?

I just put a skim coat on the water passages in the front.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Rono...

In the past I have done intake manifold gaskets this way with great success.

1. I always use some type of silicone tube RTV or something similar around the coolant ports - nothing too thick.

2. I have used the Copper-Kote spray gasket in a can because of the thin layer it puts down. I know the directions say to spray the other surfaces, but I have only ever sprayed both sides of the gasket itself and have had 0 issues... even with light pitting on some of the metal surfaces. Obviously, this sticks very well and I do this when I have no plans to remove the intake anytime soon.

3. I have also used Ted Eaton's trick by using White Lithium Grease around the intake/exhaust ports. Even when I use this method I still use a little silicone around the coolant ports... This method works well when I need to remove the intake manifold, switch them out quickly, etc. However, I have left an engine this way for quite a long time, and through many different heat cycles, and have had no issues with temp changes or longevity.

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I've used Permatex no.3 on every sealing surface. I've been using it for many years and I have yet to have a leak where I've used it.

~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

Dan,

Should I assume, that if you plan to change manifolds down the road, the white grease & silicon need only be applied to the manifold side (Copper coat or Perm. #3 would likely be the best choice for the head side)? I can see where a skim coat of silicon MIGHT be removed without gasket damage, BUT, can a gasket that has been torqued down using different manifolds be expected to seal as well as a new one long term? Gaskets aren't all that expensive, and unless you are doing a series of dyno tests (Like John), wouldn't you use the best sealant available for a final installation (?), which would naturally then indicate the use of white grease/skim coat on both sides initially. Confusing.

6 VOLTS/POS. GRD. NW INDIANA

For better or worse I just completed the intake install and decided to use a very light coat of #3 Aviation non-hardening Permatex. There was some light pitting on the intake manifold surface as well as the head ports so I just went for it. Hopefully I won't have to remove the intake for a while, but I have another set of gaskets if I do.

For those of you using white lithium grease, at a minimum please wear gloves because that stuff is very bad for your health if absorbed through the skin. I followed the suggestion of some who feel that the RTV high heat silicone is not compatable with fuel. While the directions on the tube say the same, I think the manufacturers may have been referring to it's use on fuel line fittings where the silicone would come in contact with liquid fuel and not so much in the vapor phase as in the application on intake manifold gaskets. Nevertheless, I didn't use it. Thanks to all for your comments!

Rono

  Ron Lane,  Meridian, ID