Intske manifold gasket question

[Nick88]

I'm having issues with my intake manifold gasket sealing on my 1986 383 stroker. I have tried everything. Will some of the permatex permashield that is gas resistant seal around intake ports on both sides of the gasket??? The gasket keeps sucking oil from the valley no matter what i do. Block was decked, i elongated the intake holes and tried two different intakes now, i want to avoid having to have the intake milled. Does anyone have experience with any rtv or anything similar on the intake ports of gaskets??? A reputable machine shop i know says to use ultra black but I'm worried about gas resistance, i tried indian head sealant but it didn't work.

 

[PrairieDrifter]

You need to dry fit the intake to see what you're dealing with. Chances are the block has been decked far enough through its life to have intake machining be necessary. Especially if you're having to hog out bolt holes.

If the gasket doesn't make contact, the goop will never stay sealed, not for any real length of time. The intake surface angle is not the same as the heads intake surface.

 

[Nick88]

You need to dry fit the intake to see what you're dealing with. Chances are the block has been decked far enough through its life to have intake machining be necessary. Especially if you're having to hog out bolt holes.

If the gasket doesn't make contact, the goop will never stay sealed, not for any real length of time. The intake surface angle is not the same as the heads intake surface.

I dry fit it, the intake leaks from the bottom but the bottom was touching and the top of the intake had a very slight gap, all the bolt holes line up perfectly.

 

[Sad Sack]

Using FelPro PermaTorque gaskets?

 

[Nick88]

Using FelPro PermaTorque gaskets?

They are the composite style ones meant for aluminum intakes and heads, the Grey ones not the blue.

 

[Ricko1966]

I dry fit it, the intake leaks from the bottom but the bottom was touching and the top of the intake had a very slight gap, all the bolt holes line up perfectly.

Where was the bottom touching? It's common to have to machine an intake to fit a decked blocked or angle milled heads

 

[nvrenuf]

Chinese intakes?

Ultra Black or Ultra Blue will see fine with no issues related gas contact.

 

[Broken85]

Grey Permatex (with the green writing) for gear oil is the most reliable that I have found for nearly everything. You would think the red high temp would be the most reliable, but I see it fail a lot.

Recently I put a pair of Sanderson heads on my small block and it called for NO head gaskets and instead said to only use RTV black on the high points and that’s it. I was a little more than dubious, but I did it (liberally). Shocked, not a single problem. Sealed perfect. I even went to retorque the bolts and they didn’t budge.

 

[nvrenuf]

Grey Permatex (with the green writing) for gear oil is the most reliable that I have found for nearly everything. You would think the red high temp would be the most reliable, but I see it fail a lot.

Recently I put a pair of Sanderson heads on my small block and it called for NO head gaskets and instead said to only use RTV black on the high points and that’s it. I was a little more than dubious, but I did it (liberally). Shocked, not a single problem. Sealed perfect. I even went to retorque the bolts and they didn’t budge.

My Sanderson’s have been on my motor for about 12 years with only RTV, no leaks.

 

[Nick88]

Where was the bottom touching? It's common to have to machine an intake to fit a decked blocked or angle milled heads

Touching the heads like how you would expect, but the top had a slight gap to the heads which is strange because the bottom is sucking oil.

 

[Nick88]

Chinese intakes?

Ultra Black or Ultra Blue will see fine with no issues related gas contact.

I usedfirst an edlebrock now a Weiand, both with the same issue on the intakes. So I can use ultra black with no problems? I don't need to use the rtv marketed as gas resistant?

 

[Ricko1966]

Touching the heads like how you would expect, but the top had a slight gap to the heads which is strange because the bottom is sucking oil.

As you deck the block,mill the heads,use thinner head gaskets, the part of the V where the ports are gets lower. But the intake manifold sits at the same height. I wish I could explain it better,but unless you take material off the intake manifold flanges either at the heads or the intake manifold your manifold is going to sit too high. If it wasn't decked much,milled much,not running thin head gaskets you may be okay but still needs checked. Have you run this manifold before? Have the heads been angle milled. It's weird that the flanges aren't parallel. As for height see if you can look through the manifold and see how the ports line up. You may find thinner intake gaskets and slot your bolt holes.

 

[Nick88]

As you deck the block,mill the heads,use thinner head gaskets, the part of the V where the ports are gets lower. But the intake manifold sits at the same height. I wish I could explain it better,but unless you take material off the intake manifold flanges either at the heads or the intake manifold your manifold is going to sit too high. If it wasn't decked much,milled much,not running thin head gaskets you may be okay but still needs checked. Have you run this manifold before? Have the heads been angle milled. It's weird that the flanges aren't parallel. As for height see if you can look through the manifold and see how the ports line up. You may find thinner intake gaskets and slot your bolt holes.

Never used this intake it's all new, the block wasn't decked too much as far as I know and I believe it's a 1203? Felpro head gasket which is like .042 compressed. I'm not sure about the ports as I cant see in the intake but I know the bolt holes lined up perfect each time, zero force needed to start them on the intske manifold. I tried thicker intske gasket to see if that helps but I'll try thinner if that's better. I slightly largened the bolts holes on the weiand but just barely.

 

[bucket]

When you dry fit the intakes, how close were they to the "china" wall?

Specifically what gasket part # are you using?