Intake gasket question

[kylenautique]

I'm tearing my intake manifold off and re-sealing it. I'm using the Felpro MIK 98000T gasket set. This is not my first rodeo replacing intake manifold gaskets, but they have all been on older 350s without vortec heads. I usually spray the intake gaskets with copper before sealing it up.

Is it wise to put RTV silicone or spray copper on gasket and head surface around the coolant and cylinder intake port holes? I know that overtime the aluminum can wear down and have sealing problems. I just want to do this one time. What do y'all recommend?

 

[someotherguy]

Not on a Vortec, but a TBI, I put a thin ring of RTV around each coolant port, because the heads and intake had slight pitting in those areas. Can't hurt, IMO, unless you put too much.

(edit and for those that were wondering - the MIK98000T set he referenced is same gaskets as MS98000T, just includes intake bolts for about another $5. I hadda look it up out of curiosity.)

Richard

 

[Schurkey]

I'm tearing my intake manifold off and re-sealing it. I'm using the Felpro MIK 98000T gasket set. This is not my first rodeo replacing intake manifold gaskets, but they have all been on older 350s without vortec heads. I usually spray the intake gaskets with copper before sealing it up.

Is it wise to put RTV silicone or spray copper on gasket and head surface around the coolant and cylinder intake port holes? I know that overtime the aluminum can wear down and have sealing problems. I just want to do this one time. What do y'all recommend?

These are the stock-type gaskets with the big squishy molded-in silicone sealing beads...right?

Follow the service manual procedure for them, which is probably "Clean and Dry".

DO NOT use additional silicone except as beads across the two China Walls. (NOT on the gaskets except where they touch the China Walls.)

If the heads are eroded, I'd clean them with a wire brush and solvent, fill 'em with epoxy that sets hard, sand 'em smooth using FINE sandpaper backed by a piece of plate glass (for flatness.)

Fel-Pro's official policy is that their gaskets do not need additional sealer. Permatex's official position is that RTV silicone is a gasket REPLACER, not a gasket sealer. Use RTV silicone INSTEAD of a gasket. (A "dot" of silicone at the seam between two gaskets, or the seam between a gasket and rubber seal is fine. Just not spread onto a gasket with the idea of sticking it in place.)

Having said that, I'm very likely to use a gasket sealer on paper/cork gaskets. Gasgacinch is my favorite, but there's thirty different brands of gasket sealers and any of them can work wonderfully.

 

[Pinger]

I replaced the gaskets on my Vortec last year with the Felpro ones and installed them as per Felpro's instructions.
Felpro made them so understand them was my view.

 

[someotherguy]

These are the stock-type gaskets with the big squishy molded-in silicone sealing beads...right?

Follow the service manual procedure for them, which is probably "Clean and Dry".

DO NOT use additional silicone except as beads across the two China Walls. (NOT on the gaskets except where they touch the China Walls.)

If the heads are eroded, I'd clean them with a wire brush and solvent, fill 'em with epoxy that sets hard, sand 'em smooth using FINE sandpaper backed by a piece of plate glass (for flatness.)

Fel-Pro's official policy is that their gaskets do not need additional sealer. Permatex's official position is that RTV silicone is a gasket REPLACER, not a gasket sealer. Use RTV silicone INSTEAD of a gasket. (A "dot" of silicone at the seam between two gaskets, or the seam between a gasket and rubber seal is fine. Just not spread onto a gasket with the idea of sticking it in place.)

Having said that, I'm very likely to use a gasket sealer on paper/cork gaskets. Gasgacinch is my favorite, but there's thirty different brands of gasket sealers and any of them can work wonderfully.

Fair enough, I haven't personally done a small block Vortec intake gasket set (I loathe the engines and haven't owned one other than parts trucks) so I haven't held those gaskets in my hands. I do know the part # OP bought includes the "updated" gaskets that are better than the OEM plastic crap. Looking at pics, I'd say they do not appear to be paper gaskets like a TBI application. As mentioned, in that case, I did use RTV on mine (TBI, paper) and had good results. Would they have been OK without? Dunno, but I didn't want to find out the hard way by going back in a second time.

Richard

 

[Erik the Awful]

I've installed intake gaskets dry, I've installed them with gasket compound, and I've installed them with RTV. I'm not a fan of installing them dry unless there's a known problem, or unless they have a molded in rubber section. With the factory-style Vortec gaskets, I installed them clean with a dab of RTV at the transition to the china walls. If using fiber gaskets, use gasket compound, but if the intake ports are rough, it's not a bad idea to forego the gasket compound and put a thin layer of RTV around the port. Just don't use too much, because that booger of RTV hanging into the intake does cost power.

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[tinfoil_hat]

Something I never see mentioned is sealing the bolt threads. My shop manual calls out for sealant but it's never discussed in these threads. I will have to look up the part number but the product in question functions as a sealant, threadlocker, and antisieze.

 

[twiz]

Somewhat related, I also purchased that set and I'm having trouble figuring out what this gasket goes to. I'm assuming something emissions related but I can't find anything that matches the shape.

 

[L31MaxExpress]

Somewhat related, I also purchased that set and I'm having trouble figuring out what this gasket goes to. I'm assuming something emissions related but I can't find anything that matches the shape.

IIRC that is for an air injection tube. Need one when you remove the valve cover for the manifold to clear. On California trucks the air injection tubes run across the valve covers.

 

[someotherguy]

IIRC that is for an air injection tube. Need one when you remove the valve cover for the manifold to clear. On California trucks the air injection tubes run across the valve covers.

That sucker looks every bit the classic smog pump gasket. It threw me for a while as we're not used to seeing much of that around TX.

Richard