I need a bit of advice from the SMC V8 guys on which RTV I should use to seal an iron intake manifold on the block ribs between the heads.

I've used Permatex products before and they recommend their Ultra Black Hi-Temp Silicone RTV, but is that the best product for the job - http://www.permatex.com/pro...one_Gasket_Maker.htm

I will also appreciate input on how thick to apply the goop on the ribs.

Just wants to make sure I don't get any oil leaks.

Thanks.

black, red, grey, itll all work the same imo.... and to put it on, i buy the stuff int he cheese-wiz type cans, makes a nice even bead and saves time from having to squeeze the crap outa the tube..

I use the Permatex Ultra Black Hi-Temp Silicone RTV, but I do not install the rubber spacer, just put a 1/4 thick bead of the RTV.

another vote for "ANY" rtv/silicone.
there is no real pressure, and temps are mild.
I would expect rubber cement would even work.
as to how much ---
put the peices in place, and see how much of a gap there is. depending on casting & machining - this will vary.
I myself go for roughly an 1/8" bead, on both the block & the intake, then dab it with all along, so it is "spikey", then mate the parts.

quote Originally posted by fieroguru: I use the Permatex Ultra Black Hi-Temp Silicone RTV, but I do not install the rubber spacer, just put a 1/4 thick bead of the RTV.

x2. Use a bead of black silicone and no rubbers.

Thanks to all that responded - Black Silicon RTV it will be.

I have ALWAYS used "Copper" on intakes, pans etc, NEVER had a leak. you use it WITHOUT the gasket !

quote Originally posted by Lou6t4gto: I have ALWAYS used "Copper" on intakes, pans etc, NEVER had a leak. you use it WITHOUT the gasket !

Copper? jeeeez - overkill, eh? I save copper for exhaust joints

We use the orange/red stuff in the caulk gun. Every once and a while someone puts on the gasket instead of the RTV and it makes a hell of a mess! Our engines run 24/7 on a dyno, and once every 30 hours they get shutdown to get oil and water. The ones with the gasket instead of the RTV blow all their oil out in less then 12 hours!

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Red 86GT 4 Speed "MrDrift"

Hi Freshj,

Can you be a bit more specific on your "orange/red stuff in the caulk gun"? Is that something you get from Home Depot?

http://www.permatex.com/pro...uff_Gasket_Maker.htm

quote Originally posted by 88GTS: Hi Freshj, Can you be a bit more specific on your "orange/red stuff in the caulk gun"? Is that something you get from Home Depot?

I want to say it's Permatex brand RTV, general automotive use (not home repair caulk). Comes in a caulk gun size tube. I think we get it from Napa. I did a quick google search and found some GM stuff, but not the stuff we use.

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Red 86GT 4 Speed "MrDrift"

I use 100% silicone in the caulk gun tube from any hardware store. It's cheap and one tube will last years if you keep it capped tightly. Been doing this for 25+ years.

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1986 SE 350 V8

quote Originally posted by Pyrthian: another vote for "ANY" rtv/silicone. there is no real pressure, and temps are mild. I would expect rubber cement would even work. as to how much --- put the peices in place, and see how much of a gap there is. depending on casting & machining - this will vary. I myself go for roughly an 1/8" bead, on both the block & the intake, then dab it with all along, so it is "spikey", then mate the parts.

Very little pressure but at idle 20 lbs Vacuum and on deceleration up to 30 lbs Vacuum. If you want to go over kill use "The Right Stuff". And like some of the others said any name brand RTV. Remember how hard it is to remove the manifold and think real hard when going with Rubber Cement.

There is certainly vacuum in the intake manifold at idle/decel, but I doubt there is vacuum in this area of sealing.

Rick

The seal is between the intake manifold and the engine block, so only oil to keep in.

I've talked to my favourite parts guy this morning and his recommendations are: The Permatex Ultra Black is the better of the RTVs for oil sealing, but the Permatex Right Stuff Gasket Maker that Jake recommended is the best with a better temperature range (-75 to 450F) and resistance to almost all fluids including oil, ATF and coolents. It unfortunately only comes in a half caulk tube size and is a bit more expensive (Cdn $18.00).