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By Rono - 12 Years Ago
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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
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By skygazer - 12 Years Ago
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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...
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By Talkwrench - 12 Years Ago
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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.
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By Talkwrench - 12 Years Ago
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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.
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By 312T85Bird - 12 Years Ago
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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
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By paul2748 - 12 Years Ago
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I just put a skim coat on the water passages in the front.
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By Daniel Jessup - 12 Years Ago
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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.
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By 56_Fairlane - 12 Years Ago
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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.
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By DANIEL TINDER - 12 Years Ago
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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.
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By Rono - 12 Years Ago
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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
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By brokengate - 12 Years Ago
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Fit and torque will be far more important, a measurable air flow is unlikely to be developed through "light pitting" the water more likely to find a path. A coating of anything will close light pitting, I did my water jackets only.
As for the white lithium I grew up in the house of Pall Mall non-filters, chewing the lead paint off my crib, chasing the mercury from a broken thermometer while polishing coins, getting sun burnt, eating fried chicken, tour of duty in the land of agent orange, and yup white lithium no gloves.
That said, wouldn't let the grand kids touch the stuff!
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By 56_Fairlane - 12 Years Ago
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brokengate (3/12/2013)
Fit and torque will be far more important, a measurable air flow is unlikely to be developed through "light pitting" the water more likely to find a path. A coating of anything will close light pitting, I did my water jackets only.
As for the white lithium I grew up in the house of Pall Mall non-filters, chewing the lead paint off my crib, chasing the mercury from a broken thermometer while polishing coins, getting sun burnt, eating fried chicken, tour of duty in the land of agent orange, and yup white lithium no gloves.
That said, wouldn't let the grand kids touch the stuff!
Yes, I did all that except the agent orange stuff but I could have been exposed to something far worse in some of my adventures of mixing chemicals. In addition, I rinsed my hands in various solvents, even as a kid, and played with a container so full of mercury that I could dip my hands fully into it.
Ditto on the warning for kids.
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By Daniel Jessup - 12 Years Ago
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I have only ever used a gasket for 3 intake manifolds, and that for my own testing. I have always found that the silicone comes off the metal surfaces very easily, and if the gasket is lightly gone over with a blade the gasket will be fine, especially when putting another thin layer of silicone on the gasket for reinstall.
As far as the white lithium grease is concerned, both sides of the gasket has to be recoated before reinstallation... again, the seal is excellent and the gasket will come off easily when untorqued.
I hope I was not too confusing when I listed out my numbers in the first post of 1, 2, and 3. When installing an intake that I have settled upon using for a driver I use CopperKote spray can to coat both sides of the gasket well, but not the metal surfaces themselves. If I am running my engine run stand or not settled particularly on what intake I am going to keep permanently on the engine in the car, then I use white lithium grease to help seal the intake ports.
At any rate, I always use silicone to help seal the coolant ports.
As much as I "tinker" on Y blocks with the cars and the engine run stand (A intakes, B intake, small 2 barrel intakes, large 2 barrel intakes, etc) the cost of purchasing new gaskets every time I changed out an intake to run a carb, tune, etc. would not be too feasible.
To each his own I guess.
@Ron - lots of good ideas here on the forum
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By Ted - 12 Years Ago
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Soaking the intake gaskets with WD-40 and then coating them with white grease on both sides works fine for me. After that first application, I can reuse the gaskets for at least a half a dozen intake manifold changes by just using white grease on the intake side of the gaskets. If not concerned with saving the gasket for an upcoming intake manifold change, then Copper coat is my sealer of choice.
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By DANIEL TINDER - 12 Years Ago
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[quote]
As for the white lithium I grew up in the house of Pall Mall non-filters, chewing the lead paint off my crib, chasing the mercury from a broken thermometer while polishing coins, getting sun burnt, eating fried chicken, tour of duty in the land of agent orange, and yup white lithium no gloves.
(quote) Yes, I did all that except the agent orange stuff but I could have been exposed to something far worse in some of my adventures of mixing chemicals. In addition, I rinsed my hands in various solvents, even as a kid, and played with a container so full of mercury that I could dip my hands fully into it.
I've got both you guys beat! I once had my own indoor shooting gallery with a concrete backstop in the early 70s. Many a night I spend the entire evening standing there inhaling huge clouds of lead dust from cheap, soft nosed 22 ammo. It's lucky I can still remember my own name.
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