RTV for end gaskets on intake

[Steve D.]

63 convertible

I have just reset the intake manifold, and have used the RTV Copper to form the gasket as recommended by Joe L. How long should I wait before torquing down the manifold. The verbiage on the tube says it take 24 hours to fully cure.
I should have asked before I set the manifold down, but it didn't occur to me until I started threading in the bolts.

Steve

[Edward J.]

Re: RTV for end gaskets on intake

Torque The Manifold As Soon As You Set Manifold Down, This Way It Conforms To The The Engine Block And Sets Up That Way And Then Let Stand For A Few Hours.

[Steve D.]

Re: RTV for end gaskets on intake

Ok to start the engine after a few hours?

[Edward J.]

Re: RTV for end gaskets on intake

I would recm. three to four hours is okay. but read the container sometimes they give you the set time.they all tend to be different.

[Brandon T.]

Re: RTV for end gaskets on intake

I've always used Permatex ULTRA black form a gasket for my intakes.

give it a try

[Joe L.]

Re: RTV for end gaskets on intake

63 convertible

I have just reset the intake manifold, and have used the RTV Copper to form the gasket as recommended by Joe L. How long should I wait before torquing down the manifold. The verbiage on the tube says it take 24 hours to fully cure.
I should have asked before I set the manifold down, but it didn't occur to me until I started threading in the bolts.

Steve

Steve------


As soon as the Ultra Copper starts to "skin over", install the manifold and torque it down. This just takes a few minutes from the time you lay down the RTV. Make absolutely sure that the manifold and block contact surfaces are are COMPLETELY free of ANY oil or grease. Clean with brake cleaner. I even recommend the use of a primer, but it's not essential.

Also make sure that you apply the RTV so that the bead of gasket extends up onto the "tabs" of the side gaskets with a little extra "blob" at this point. After the RTV cures, you can trim off any "squeeze out" with an Exacto knife or razor blade.

4 hours should be enough cure time but, to be safe, I like to let it cure at least overnight.

[Tom P.]

Re: RTV for end gaskets on intake

Torque it down as soon as the manifold is in place.
I personally don't wait for any curing time when using RTV for front/rear of manifolds. As soon as the RTV is applied, I set the manifold in place and toruqe it down.
I like to wait about 6hrs before starting the engine.
Also, I apply a THICK bead of RTV to assure everything is thoroughly sealed. The excess which squeezes to the outside can be neatly trimmed off after it is fully cured using an Exacto knife, razor blade, etc. The excess that squeezes to the inside will just stay there forever.

[Paul L.]

Re: RTV for end gaskets on intake

Torque it down as soon as the manifold is in place.
I personally don't wait for any curing time when using RTV for front/rear of manifolds. As soon as the RTV is applied, I set the manifold in place and toruqe it down.
I like to wait about 6hrs before starting the engine.
Also, I apply a THICK bead of RTV to assure everything is thoroughly sealed. The excess which squeezes to the outside can be neatly trimmed off after it is fully cured using an Exacto knife, razor blade, etc. The excess that squeezes to the inside will just stay there forever.

Is there a difference between the copper and black Permatex?

[Edward J.]

Re: RTV for end gaskets on intake

Paul, there about 10-15 types of RTV sealant on the market all have different qualitys and different types of uses but basicly used for the same automotive uses, some work better around high temp.s some work better on oil pans ,valve covers, tranmissons, alumnim, cast iron.


My shop uses a permatex brand its called the Right Stuff, excellent all around use, the seal is superior to most that I have used. as with most RTV sealants the cleaner the surface the better the seal.as Joe L. say braker cleaner is great to remove any oilly film that most of us cannot see.

[Terry M.]

Re: RTV for end gaskets on intake

Also, I apply a THICK bead of RTV to assure everything is thoroughly sealed. The excess which squeezes to the outside can be neatly trimmed off after it is fully cured using an Exacto knife, razor blade, etc. The excess that squeezes to the inside will just stay there forever.

I wish that were true, but after cleaning the oil pump intake screen on several engines -- one of which was so bad the main bearings also required replacement -- I know that the excess RTV will remain inside the engine but not where it was applied.

[Tom P.]

Re: RTV for end gaskets on intake

I wish that were true, but after cleaning the oil pump intake screen on several engines -- one of which was so bad the main bearings also required replacement -- I know that the excess RTV will remain inside the engine but not where it was applied.

I have always used the Ultra Copper and have not had this problem. Possibly some others are prone to coming loose inside the engine.

[Edward J.]

Re: RTV for end gaskets on intake

Tom, most RTV sealants do warn of excessive amounts, sometimes more is not always better, that is the case of RTV sealants. as Terry states it does make its way to the bottom of oil pan overtime, if drawn into oiling system it will create problems, especially so on high preformance motors.

[Jim T.]

Re: RTV for end gaskets on intake

I wish that were true, but after cleaning the oil pump intake screen on several engines -- one of which was so bad the main bearings also required replacement -- I know that the excess RTV will remain inside the engine but not where it was applied.

When I bought my 1985 from the original owner in 1992 I also got the previous repair invoices (some people are really organized). I had some oil seepage/leaks from both valve covers and removed them to install new gaskets. Discovered from the invoices that the local Chevrolet dealership had used the RTV silicone stuff to seal the gaskets instead of cork. The RTV was also wrapped around some of the pushrods on both sides of the engine from the generous application of the RTV. Don't know what may be in the oil pan, will someday when I get around to replacing the rear seal.

[Brandon T.]

Re: RTV for end gaskets on intake

ultra black is for heat, better to go with the best one for heat not that its needed on the intake for better safe than sorry.

so that I've read anyway.

[Joe L.]

Re: RTV for end gaskets on intake

I have always used the Ultra Copper and have not had this problem. Possibly some others are prone to coming loose inside the engine.

Tom-----


Yes, when cured Ultra Copper has a very high durometer. It's VERY tough. I don't worry about any inner "squeeze-out" becoming "dislodged". In fact, that's one of the advantages of using Ultra Copper.