Intake Gasket Oil Stain

[JD Erisman]

That’s an odd title, I couldn’t figure out how else to summarize my issue. Engine is a three thousand-mile 408 stroker, Trick Flow heads with a six pack. Started losing a lot of oil out the back of the intake after a high RPM acceleration.
I used Edelbrock intake manifold gaskets with Gasgacinch applied to the cylinder head side. I didn’t use cork gaskets on the china rails, just gray RTV, I’m assuming the oil leaks are in that area.

When I pulled the intake manifold off I saw a lot of oil staining on each intake gasket in the area of the heat crossover, see pictures. There appeared to be oil inside of the manifolds heat crossover channel, but it was difficult to tell if the oil was in the channel or simply dripping off the bottom of the intake. I’ve haven’t seen this type of gasket staining on a motor I’ve torn down before.

On the exterior of the engine, in the area above each heat crossover port, I had very minor oil breaching the seam between the head and the intake manifold, below the valve covers, not really a leak but noticeable residue. I assume this oil residue is related to the oil staining I see on the intake gaskets.

When I lay a straight edge across the span of intake ports on each side of the manifold the surfaces are level and even.

I have used another intake manifold, RPM Air Gap, on this same block/cylinder head combination without oil leaks.

Is there anything else I should check to resolve the oil leak in the area of the crossover? Is this oil staining a minor issue and not uncommon?
Any advice would be appreciated.

 

[CRUZE 418]

I have the same set up. I had to cut my intake, the sides and the China rails. But, if you were able to get the bolts in, you did not have the same issue. Having said that, you had another intake that did not leak. How even is the intake bite from top to bottom of the intake port? How thick are your intake gaskets? .060? May have to have your intake checked with machining pass. You will have a little more investigating to do. I have to pull my intake, rear carb base is warped, sounds like you may have a similar issue.

 

[dano]

Mock it up with new gaskets and check. Even check the China wall with the end corks, if they slide in, lightly grey RTV them and use them. RTV is not a large void filler plus on some intakes the wall doesn't line up well with the intake machined area for the seals.

What are you running for a crank case evacuation system?

 

[JD Erisman]

I had to enlarge all of the bolt holes on the RPM Air Gap to make them line up with the bolt holes in the Trick Flow heads. I don’t recall exactly how well the intake ports aligned between the manifold and the heads but I think they were pretty close, I don’t remember having a misalignment issue. That manifold is on another engine or I would check it.

The bolt holes on the six pack intake line up with the holes in the heads but I will mock it up again and try to see how it’s resting on the cylinder heads, whether the mating surfaces are flush with each other.

The gaskets are 0.060” thick but the Edelbrock gasket set does not come with end gaskets. I’ve never been a fan of the RTV glob but I know a lot of guys do it with good results. I was surprised when I removed the intake, not a bit of RTV was stuck to it, all of it remained on the block.

Reference the evacuation, the only thing I am using is a PCV valve, though I don’t remember what engine the valve is listed for. Likely a 340 or 360 valve for an early 70s.

 

[Illahe]

I had to enlarge all of the bolt holes on the RPM Air Gap to make them line up with the bolt holes in the Trick Flow heads. I don’t recall exactly how well the intake ports aligned between the manifold and the heads but I think they were pretty close, I don’t remember having a misalignment issue. That manifold is on another engine or I would check it.

The bolt holes on the six pack intake line up with the holes in the heads but I will mock it up again and try to see how it’s resting on the cylinder heads, whether the mating surfaces are flush with each other.

The gaskets are 0.060” thick but the Edelbrock gasket set does not come with end gaskets. I’ve never been a fan of the RTV glob but I know a lot of guys do it with good results. I was surprised when I removed the intake, not a bit of RTV was stuck to it, all of it remained on the block.

Reference the evacuation, the only thing I am using is a PCV valve, though I don’t remember what engine the valve is listed for. Likely a 340 or 360 valve for an early 70s.

I'd try spraying the gaskets with this, after you confirm that your intake manifold is at the same pitch as your cylinder head. A couple of coats on each side.

 

[dano]

Reference the evacuation, the only thing I am using is a PCV valve, though I don’t remember what engine the valve is listed for. Likely a 340 or 360 valve for an early 70s.

Are you using a breather on the opposite side or a 5/8-3/4 tube to the air cleaner lid?

 

[mygasser]

if the rtv didn't stick to the intake then it wasn't cleaned/degreased fully. if a face is clean and dry rtv 'will' stick, no if's, but's or maybe's.
neil.

 

[CRUZE 418]

Elongating holes for me would be a red flag, but I am not there. I had to cut the sides and China rails of my Sixpack, yeah, probably will never fit another engine!

 

[JD Erisman]

if the rtv didn't stick to the intake then it wasn't cleaned/degreased fully. if a face is clean and dry rtv 'will' stick, no if's, but's or maybe's.
neil.

I agree, I’m normally pretty clean when I put an engine together but I must have only cleaned the block and not the intake.

 

[JD Erisman]

Are you using a breather on the opposite side or a 5/8-3/4 tube to the air cleaner lid?

I have a breather on the opposite valve cover from the PCV but I see where you are going. I’m going to check the PCV and my breather cap, which is also the oil cap.

 

[JD Erisman]

Elongating holes for me would be a red flag, but I am not there. I had to cut the sides and China rails of my Sixpack, yeah, probably will never fit another engine!

I agree but I did some reading beforehand and it doesn’t seem too uncommon. However, that doesn’t make it a good idea. I couldn’t get a good alignment otherwise. I don’t know if the Trick Flow heads are making for an odd angle for the intakes to rest on, maybe but seems unlikely.

 

[MOPAROFFICIAL]

That’s an odd title, I couldn’t figure out how else to summarize my issue. Engine is a three thousand-mile 408 stroker, Trick Flow heads with a six pack. Started losing a lot of oil out the back of the intake after a high RPM acceleration.
I used Edelbrock intake manifold gaskets with Gasgacinch applied to the cylinder head side. I didn’t use cork gaskets on the china rails, just gray RTV, I’m assuming the oil leaks are in that area.

When I pulled the intake manifold off I saw a lot of oil staining on each intake gasket in the area of the heat crossover, see pictures. There appeared to be oil inside of the manifolds heat crossover channel, but it was difficult to tell if the oil was in the channel or simply dripping off the bottom of the intake. I’ve haven’t seen this type of gasket staining on a motor I’ve torn down before.

On the exterior of the engine, in the area above each heat crossover port, I had very minor oil breaching the seam between the head and the intake manifold, below the valve covers, not really a leak but noticeable residue. I assume this oil residue is related to the oil staining I see on the intake gaskets.

When I lay a straight edge across the span of intake ports on each side of the manifold the surfaces are level and even.

I have used another intake manifold, RPM Air Gap, on this same block/cylinder head combination without oil leaks.

Is there anything else I should check to resolve the oil leak in the area of the crossover? Is this oil staining a minor issue and not uncommon?
Any advice would be appreciated.

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Aluminum heads. Don't glue the gaskets to the entire face of the aluminum head with gasket cinch. Use some Indian Head shellac, Permatex makes it. Simply paint a little around the intake Port windows, , around the water crossovers..and just a dot on each side of the exhaust riser port. Gasket cinch is more like a cement, while Indian Head is more like a perma-tack.. as to where it will adhere but has a more elasticity to it which I believe helps with different rates of expansion. I have had those Edelbrock gaskets completely delaminate and do weird things when I've painted the entire intake face of the head to adhere the gasket. Gasket cinch is no longer my favorite needless to say.
As for seeing them get a little oil soaked.. usually I see gas stains, not oil. If you ever get a situation of a stuck needle and seat intake Runners can load up with fuel and that can soak through the gasket. It doesn't mean that it's going to leak all of a sudden it just means that the gasket has been wet and stained. If you're running a PCV, put it on the driver side.

 

[CRUZE 418]

I too have Trick Flow heads.

 

[JD Erisman]

I’ve never used the Indian Head but I’ve seen it recommended in other threads here, I’ll definitely buy some and apply where you suggested. These are the first aluminum heads I’ve used and I likely do not know enough about their differences from an all iron heads in regards to mating with an iron block.
I placed the intake, port gaskets only, on the heads/block. I have a gap on the China rails that is a bit small for the cork end gaskets, see photos. The bolt holes on both sides lined up ok but not perfectly.

When I placed the cork end gaskets the intake was raised higher than I feel comfortable with. The cork’s thickness caused the intakes bolt holes to be slightly too high and the intake far enough away from the heads I would worry about breaking /cracking the intake when tightening the bolts. Though I don’t like using a bead of RTV on the China rails I may not have a choice.
CRUZ 418, what bolts are you using to hold down your six pack intake? Length, specifically.

 

[dano]

I’ve never used the Indian Head but I’ve seen it recommended in other threads here, I’ll definitely buy some and apply where you suggested. These are the first aluminum heads I’ve used and I likely do not know enough about their differences from an all iron heads in regards to mating with an iron block.
I placed the intake, port gaskets only, on the heads/block. I have a gap on the China rails that is a bit small for the cork end gaskets, see photos. The bolt holes on both sides lined up ok but not perfectly.

When I placed the cork end gaskets the intake was raised higher than I feel comfortable with. The cork’s thickness caused the intakes bolt holes to be slightly too high and the intake far enough away from the heads I would worry about breaking /cracking the intake when tightening the bolts. Though I don’t like using a bead of RTV on the China rails I may not have a choice.
CRUZ 418, what bolts are you using to hold down your six pack intake? Length, specifically.
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Yeah that's too thin for the ends. Time for the The Right Stuff to come out.

 

[CRUZE 418]

Just used standard intake bolts, do not use the cork China rail gaskets. My intake fit perfectly without any gaskets, if I layed the intake gaskets in, the holes were all high. Aluminum heads strip easily if your threaded holes and the intake holes do not almost align perfectly. You have to use a feeler gauge to check if you think that your intake is not laying in there correctly. Torque is also I important, I had to keep doing this until the torque settled down. I also retorque my heads, people here will argue, but there are always 3-6 that need it. Just be careful with threads in aluminum, intake or exhaust. Not related, but what is your valve train? You can pm me.

 

[JD Erisman]

Thanks to everyone for all of your help, I’ll keep working on it.