BEVO76

Hope yall are well! Haven't been on in a while, nonetheless I'm stumped on the intake with my new 383 leaking from the rear.

The intake is a Professional Products Crosswind. This weekend will be th third attempt. On the first attempt the black RTV bead was paper thin from which I assume the tolerances were off. The second time I doubled up the gaskets to gain 1/8 clearance to get a better bead, which now also failed.

The builder is either going to machine the current intake or swap it for an Edlebrock RPM Air Gap.

This engine does have a ton of oil pressure. 35 at idel and 70 at 60-70mph.

Is there something I'm missing.

BEVO76

I will say the 383 is a beast! Can't wait to hit the 1/4 mile. I did manage to bust the tires loose and walk the car sideways which was without doubt the best part of my day!!! Just can't figure out this oil leak!

BEVO76

Thoughts!?!? Anyone...

DucatiDon

Oil leak on a bolt, or at the china wall? Sounds like your intake is not sealing...no vacuum leak tho?

Where exactly is the oil leaking from?

BEVO76

Rear intake oil leak directly under distributor. Leaking down passenger side of rear block onto starter bolts and trans shroud. If you take the Dist out and move the RTV with ur finger you can see air bubbles on the inside of the Dist hole.

BEVO76

No vaccum leak and breather / PCV are working fine

bluedawg

I always put about 3/8" rtv bead on the China wall at the back edge and wait until it has enough crust not to stick to my finger and torque the intake, you should see the rtv squeeze out slightly when you torque it down. The second place back there that leaks is the port for the oil pressure gauge, which I put a slight bit of rtv on the threads. The smaller the gap on the China wall the easier it is to seal. The right stuff seals about the best, but is harder to clean off if you remove the intake. It's a little disturbing that your engine builder is having issues sealing your intake, but the intake could be a bad casting. Unless your ports don't align you shouldn't need a double gasket, but sometimes decking the block or milling the heads can cause alignment issues, decking the block could also narrow the gap at the china wall but if you do need a thicker gasket, Felpro makes a .125" intake casket instead of using two .0625". Good luck with your project.

Haggisbash

I agree with Bluedawg but what I also do is add a light smear of fresh sealant over the main bead of silicone once this has "skinned" to key it to the manifold surface. I use high temp RTV gasket maker. My inlet manifold leaked at this spot even with silicone sealant there until I did it this way.

cagotzmann

Are you using this product ? the ultra black version.
http://www.permatex.com/products-2/p...t-maker-detail

I found this worked great with my Stock L48. I had the same issues 4 attemps until I used plenty of this on both ends.

Shark Racer

You should also make sure the mounting surfaces are clean of oil and grease, or the sealant will not bond with the surface.

bluedawg

True story.

diehrd

If you have done this 3 times I would say add breathers to valve covers. People under estimate blow by and the pressure it creates in the crank case under spirited driving conditions.

Pull Pcv plug hose pull oil cap and replace both with breathers . See if that stops the rear intake leak

BEVO76

This will be the third time on SAT.

I think there is something going on with the manifold. The first time I took the manifold off the RTV was less than paper thin. So thin it you could scrape it off with just a fingernail.

BEVO76

the surfaces are spotless

BEVO76

I have used both ultra black and ultra gray

HBZ_81_C3

My intake is relatively tight on the china wall as well. The last time I had the intake off I decided to try the adhesive backed cork gaskets that came in the Fel-Pro 1206 gasket kit. I cleaned everything, stuck them to the china wall and put a dab of "The Right Stuff" Permatex in the corners and bolted everything together. I was pleasantly surprised...with not as much as a weep from the manifold.

Just to add, I run breathers in both valve covers as mentioned... no PCV.

BEVO76

HBZ - really starting to wonder about the double breathers.

I wish I had a picture of what the RTV looked like when I took it off the first time. It was paper thin to the point where it was almost transparent....was yours that thin?

I do have a ton load of oil pressure 35 at idle and 70 at 60-70mph, I am wondering if that has something to do with it.

The PCV and breather are working. However, I am only 300 miles into this new engine. But that shouldnt matter as im pretty sure the rings are sealed.

bluedawg

Die hard makes a really good point, if it builds pressure in the crank case it will force leaks. I run a pvc on one side and a grommet on the other that is blocked off, but I drilled 3 1/8" holes so that it can't suck much air.

BEVO76

I dont get it? what did you drill holes in to limit the pressure?

BEVO76

I wonder if adding a second breather would fix my issue? I do not ever recall running a PCV on any of my race engines back in the day....hmmmmm!?!?! and this engine is very far from stock.