I'm aware that it's a good idea to use Silicone sealer on the front and back of the intake manifold, but is it also necessary to use it on the cylinder head-to-intake mating surfaces?

Will a good gasket prevent the coolant from leaking and prevent vacuum leaks?

Any help is appreciated,

Jason

 

This is what I do.

Run a big fat bead accross both lifter valley ends on the block. Throw away the end seals they give you.

Put a little around each water passage on both sides of the intake gasket. (just spread a little with yout finger)

Thats all. I don't put anything on the intake ports or the ex. crossover port.

What I also do is to use a center punch and lightly punch a bunch of dots accross the intake manifold and block where the lifter valley ends are. This gives the silicon something to adhere to.

I also use liquid teflon sealer on all the intake bolts to avoid "mytery" oil leaks up the threads of the bolts.

ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited December 10, 2000).]

 

Thanks for the help Engineboy,

Jason

 

i use the china wall gaskets ,if i have the engine on a stand, other wise i do as engine boy said. i too use a center punch and mark the china wall and intake for the gasket or silicone to hold on to.

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ICON Motorsports
1st & 3rd

 

I don't know why you guys insist on getting rid of the end seals and replacing it with silicone...

I used RVT Black on both sides of the seals and some red Loctite on the bolts and I've NEVER had a leak.

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The '82Z
Hugger Orange
383 4 bolt main
3000 lbs
Bad cornering
NOS Sportsman Fogged
10 bolt braker

Coming to a street near you in the spring...
The car's website

 

read it again crazeinc, i said i use the china wall gaskets. the risk of them shifting i why i don't when the engine is in the car. you can't tell if it's in place or not. last gasket set i bought,fel-pro, had black silicone instead of the china wall gaskets.

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ICON Motorsports
1st & 3rd

 

i have had the gasket shift around on the rear side and leak. couldn't see it untill it blew oil all over the firewall. that was way back in the days before high tack, that stuff is great for sticking a gasket and not having it move on you.

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ICON Motorsports
1st & 3rd

 

When you buy a new Edelbrock manifold the instructions also say to throw away the end gaskets and use silicone.

Something not mentioned yet but if your car still uses an O2 sensor then make sure you use sensor safe silicone/RTV.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
454 Big Block buildup now in progress for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car
91 454SS daily driver
95 Homebuilt Harley

 

The reason I don't use gaskets on the "china wall" is because I have to gurantee these engines I install won't leak anything.

This isn't my car that if it leaks I just fix it. These are customers cars that if they leak I fix it for free.

If there is any chance of a leak I won't take the chance. The end seals are high failures. They can be, and I have installed them right but they are prone to leak.

I just go with what I have the best results with. I put too many engines in a year to take chances with them.

A side note:

When not using end seals, make sure you get all the paint off the block where the silicon will be. I have seen the paint "pop" off the block and since the silicon is sealed to the paint, oil will leak under the paint. I just clean all surfaces down to metal.

However you decide to do it...good luck with your install



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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

Engineboy, what's this china wall you refer to as being. I soon will be replacing my intake gaskets.

 

I swear by Ultra Blue RTV...I've used black two or three times and it always leaked...this is partly due to my own incompetence...but black has a much more picky set time than blue...I make one fairly thick bead of blue and if it ever gets too thin wipe it off and start over...you do NOT want leaks! Then let the two beads cure for about 15-20 min and set the manifold on as gently and straight as you can, with the goal being not to move it at all once it's down. I used a dremel to cut the heads off a bunch of bolts so that i can screw in the studs and guide a manifold or water pump down without having to shift it afterward. Good Luck!

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89 Iroc-Z LB9 305 TPI auto 2.73 posi:
3" Dynomax "cat" back,K&N filters, TB bypass, 3" pipe in place of cat, cleaned and flow-matched injectors, 170' thermo, mild ignition mods, synthetic oil, kicker sound system, soon to have 3.73 posi...

 

Hey I Rock, I used to swear by Ultra Blue too. If you think that stuff is good, you oughta try "The Right Stuff". It's made by permatex as well. It comes in a can, and it costs a bit more, but it has the perfect consistency. Also, it makes building up the bead on the china walls a piece of cake because you just push the nozzle and dispense away! For the guy who was wondering what the "china walls" are, they're the surfaces on the front and the back of the engine block that your intake manifold rests on.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

Ya, what Pat said.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3