Intake oil leak

[1973dust]

I know this has been covered before, but thought someone might have recent experience. 318 with Edelbrock Performer. After about 600 miles, leaking at china rails, front and rear. I used Ultra Black rtv but maybe not built up high enough? No issues at all with the intake to head gaskets and dowel pins are removed. I don't know which fix would be best. I bought a tube of "The Right Stuff" which several of you swear by. I also thought about making my own gaskets for the rails as the standard cork gaskets are too thick as usual for an aftermarket intake. I have a roll of cork gasket material and a roll of fiber gasket material that would take up most of the gap. Thanks for any opinions.

 

[Phreakish]

Rtv. I buy the caulking gun tubes.

You need to be careful with placement of the bead and also ensure you get enough on there.

Also clean all surfaces with a solvent soaked rag. I use acetone or brake clean sprayed on a CLEAN rag.

 

[George Jets]

Ultra Black RTV is good stuff.

Just checking did you degrease your mating surfaces with Brake Parts Cleaner before assembly to remove any oil film ?

I would hit the leak areas at the china wall with Brake parts cleaner and compressed air quick.

Then would take a razor knife and cut back the RTV at a 15° angle down from the intake manifold down to the center of the china wall. Then hit real quick again with brake parts cleaner and compressed air for a final clean.

Then put another new bead of RTV on, let dry overnight before starting the engine so it sets up properly and seals.

Good to Go . . .

This 318 intake pictured hear is sealed with Ultra Black RTV Gasket Maker. If you expand up the picture you can see it well.

No leaks front or rear china wall . . .

Can run a wet finger over the bead of RTV one time right away, to help shove it in there. Makes it look nice, and can clean up excess with a wrag.

 

[1973dust]

Ultra Black RTV is good stuff.

Just checking did you degrease your mating surfaces with Brake Parts Cleaner before assembly to remove any oil film ?

I would hit the leak areas at the china wall with Brake parts cleaner and compressed air quick.

Then would take a razor knife and cut back the RTV at a 15° angle down from the intake manifold down to the center of the china wall. Then hit real quick again with brake parts cleaner and compressed air for a final clean.

Then put another new bead of RTV on, let dry overnight before starting the engine so it sets up properly and seals.

Good to Go . . .

This 318 intake pictured hear is sealed with Ultra Black RTV Gasket Maker. If you expand up the picture you can see it well.

No leaks front or rear china wall . . .

Can run a wet finger over the bead of RTV one time right away, to help shove it in there. Makes it look nice, and can clean up excess with a wrag.

View attachment 1715563325

Yes, I cleaned the mating surfaces with brake parts cleaner. Probably didn't get a high enough bead. I also let everything cure for a day after torquing before I refilled with coolant and oil. I did have some trouble getting all of the bolts started, so maybe that had an effect on the rtv sealing. Everything looked good when I dry-fit but on actual installation, I fought several of the bolts. Ended up having to use the factory bolts with the turned-down lead-in to get the bolts started and intake pulled down. Then replaced those with the Edelbrock 12 points. In hindsight, I'm not sure that the Edelbrock bolts were really necessary.

 

[George Jets]

Did a 1/4" bead of RTV on the intake, after 1st putting a thin layer on both surfaces, then a 1/4" bead on the china walls.

My trick is I set the manifolds on with the cherry picker so it comes in nice and straight and level.

Then put all the bolts in and snug them up, then final torque them.

Then go back and put the final filler coat of the RTV on and smooth it out with a wet finger.

 

[1973dust]

Did a 1/4" bead of RTV on the intake, after 1st putting a thin layer on both surfaces, then a 1/4" bead on the china walls.

My trick is I set the manifolds on with the cherry picker so it comes in nice and straight and level.

Then put all the bolts in and snug them up, then final torque them.

Then go back and put the final filler coat of the RTV on and smooth it out with a wet finger.

That's probably my problem. I put one bead on the china rails but none on the intake itself. I was worried about using too much. Do you still think I have a chance to get it sealed without pulling the intake? I know the back isn't going to be very easy to get to and it seems to be leaking worse than the front.

 

[George Jets]

That's probably my problem. I put one bead on the china rails but none on the intake itself. I was worried about using too much. Do you still think I have a chance to get it sealed without pulling the intake? I know the back isn't going to be very easy to get to and it seems to be leaking worse than the front.

Yes you can get it resealed with the intake on.
I would get it up on #1 on compression at TDC and pull out the distributor so you can get in there and work. Put a mark on your intake manifold to where the Rotor is pointing so you will have it back in time when you put it back together.

Like I say if you can get in there and cut out some of the RTV with a razor blade, then the new RTV has a shelf to sit on and help hold it in there.

Definitely need to do a quick spray with brake parts cleaner and compressed air once you cut out some of the old RTV to remove any oil film that got through. Don't leave the Brake Parts Cleaner on very long as it actually dissolves the RTV. The new RTV will stick to the old then.

Sometimes have to be creative with tools like an extension on a wire wheel so you can reach down in there and grind out some of that old RTV as an alternate way of prepping it for the next application.

Can weld on a length of 1/4" brake tube to the wire wheel for added reach. Shove a wrag in the distributor hole to keep debris out or tape it closed.

Small mirrors work good for looking in there to see what you are doing.

 

[1973dust]

Yes you can get it resealed with the intake on.
I would get it up on #1 on compression at TDC and pull out the distributor so you can get in there and work. Put a mark on your intake manifold to where the Rotor is pointing so you will have it back in time when you put it back together.

Like I say if you can get in there and cut out some of the RTV with a razor blade, then the new RTV has a shelf to sit on and help hold it in there.

Definitely need to do a quick spray with brake parts cleaner and compressed air once you cut out some of the old RTV to remove any oil film that got through. Don't leave the Brake Parts Cleaner on very long as it actually dissolves the RTV. The new RTV will stick to the old then.

Sometimes have to be creative with tools like an extension on a wire wheel so you can reach down in there and grind out some of that old RTV as an alternate way of prepping it for the next application.

Can weld on a length of 1/4" brake tube to the wire wheel for added reach. Shove a wrag in the distributor hole to keep debris out or tape it closed.

Small mirrors work good for looking in there to see what you are doing.

View attachment 1715563412

Thanks, I'll give it a shot.

 

[Plymouth 65]

I make my own gaskets using the thinner fiber material. Then use a good amount of silicone. Make sure to get the transition surfaces between the China wall and head with a bead. I've never had an issue with this combination. I've used only silicone without the thin gasket and it's always leaked. JMO 65'