Proper intake manifold gasket install
Thread Starter
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Proper intake manifold gasket install
I used a regular Fel-Pro blue when I assembled the motor and later read Edelbrocks warning never to use fel-pro blue with aluminum. Apparently aluminum doesn't have the clamping force to properly compress the gasket. Sure enough, I think I have an intake vacuum leak.
Went and got a fanzy Reinz Nitroseal gasket (Reinz is OEM for GM and is used on the LS1, LT4 etc).
Now my question: I already know not to use the end-seals and use a bead of RTV instead. But what about the water and intake ports? Should I leave them clean? Service manual says use sealer around water ports, but the manual was written 30 years ago... These are new types of gaskets. So:
1. No sealer.
2. RTV around water ports, no sealer around intake ports.
3. RTV on water and intake ports.
4. RTV around water ports, gaskacinch around intake.
Which of the above is correct? Is there a #5?
BTW, Engine has Aluminum heads and intake. My EFI manifold does not have the bolt holes between intake ports (4 bolts less than stock) so getting the above right is essential as clamping force is less than with a stock style manifold.
Went and got a fanzy Reinz Nitroseal gasket (Reinz is OEM for GM and is used on the LS1, LT4 etc).
Now my question: I already know not to use the end-seals and use a bead of RTV instead. But what about the water and intake ports? Should I leave them clean? Service manual says use sealer around water ports, but the manual was written 30 years ago... These are new types of gaskets. So:
1. No sealer.
2. RTV around water ports, no sealer around intake ports.
3. RTV on water and intake ports.
4. RTV around water ports, gaskacinch around intake.
Which of the above is correct? Is there a #5?
BTW, Engine has Aluminum heads and intake. My EFI manifold does not have the bolt holes between intake ports (4 bolts less than stock) so getting the above right is essential as clamping force is less than with a stock style manifold.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Proper intake manifold gasket install (zwede)
Use Permatex #2 around the water ports. Its different than rtv. Ive had no problem using cork end gaskets when I glue then inplace with 3M weather strip adheasive. then use a dab of rtv in the corners front and back. I also use the 3m adheasive to glue the intakegaskets in place. it sets to a soft set pretty quick and holds them in place when you drop the manifold down. so thats it
1. permatex #2 on both sides of the intake waterports
2. 3m for holding end seals in place and rtv on the corners or a thick bead of rtv across the ends if you prefer.
1. permatex #2 on both sides of the intake waterports
2. 3m for holding end seals in place and rtv on the corners or a thick bead of rtv across the ends if you prefer.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Proper intake manifold gasket install (zwede)
My manual specifically says and ive also read the same in the gasket kit instructions to use permatex #2 for the water ports on both sides of the gasket. I think the that rtv in that location is prone to leaks. im not saying it wouldnt work. Im just repeating what ive always read as the recomendation for any water port including thermostat gaskets as well. #2 is the same stuff they recomend for head bolt threads as well.
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Proper intake manifold gasket install (zwede)
I have used a very thin coat of RTV around the water passeges the four times I have intalled my alum intake with alum heads on three diff eng with no leaks. I have also intalled the end gaskets using super tack sealer on teh bottom and rtv ont he top having it seal fine once and leak once. I have also intalled with no end gaskets, just rtv, with it leaking once and not leaking the other so it is a toss in my book with regards to the end gaskets.
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Re: Proper intake manifold gasket install (zwede)
RTV around water ports, and intake to head corners. I'd also throw away the forward/rear cork or rubber block gaskets and use a 1/4" bead of RTV instead. Even with the rubber "****" seated in the block....I still blew out the rubber during the dyno. RTV has held ever since.
Eddie
Eddie
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Proper intake manifold gasket install (zwede)
I don't think there is one "correct" way. In the past when I was dealing with stock heads and stock intakes, I've always just put RTV (Ultra Copper) around the water ports and a dab at the corners. This has always worked out for me. I also used the end peices with no problems.
I don't think so. This will guarantee that there will be no leaks. On my current engine, I have to RTV the ports as I have a small mating problem, and getting that fixed by milling is way to much $$ and a crapshoot at best. So, now I use Ultra Black around the ports and Copper around the water passages. I believe the scare is that RTV is not supposed to be used where it will be in contact with gas. I have called Permatex and they said it would be OK for this application. I also pulled the intake after 10k miles and the RTV was still holding strong. I still use the end peices as I'm afraid I'd put too much RTV in their place, and have had good results.
So RTV around the intake ports would be a bad idea?
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
