Help with intake leak causing oil smoke - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 4 (permalink) Old Jun 7th, 02, 04:26 PM Thread Starter
Senior Tech
Join Date: Sep 2000
Location: Central FL
Posts: 271
I need advise on getting an intake to seal. It keeps leaking oil past the gasket at the bottom of the intake ports. Here's the long story:

I posted recently about smoke on startup sometimes and when shifting, and that I suspected the intake or valve seals. Well I pulled the intake last weekend and sure enough there was oil all over the gasket at the bottom of the ports. And I could see oil puddled above each intake valve. I changed the gaskets and used some Permatex Hylomar on both sides of each as recommended in a post on the same topic recently "Smokin Merlin 509". (Psalm69, did you get your intake sealed?)

That didn't work, it still smoked. I pulled the intake back off, and sure enough, there was oil on the gaskets at the bottom of the ports, and oil puddled above the intake valves. I cleaned all the oil from above the valves and sqirted oil above the valve seals to confirm none leaked, and no oil leaked past the seals. I checked all surfaces with a straight egde, and all seemed flat. So I suspected maybe the two surfaces were at a slightly different angle. I checked the best I could and they seemed the same.

I then tried a new gasket and used Permatex Form-a-Gasket #1 on both sides of each gasket. Since it was Sunday, and I work out of town during the week, I decided to not start it up until I got home this weekend, to let the sealant set up real well. So today I cranked it up. It smoked real lightly the first time, which I figured was some left over oil from before. But it did smoke some when I reved it. I let it run for a while and shut it off and let it set to see if oil would puddle again and smoke on startup. Sure enough, when I cranked it later it let out a puff of smoke. I'm sure the intake is still leaking. But I don't want take it off again until I have a plan to make sure I get it right next time.

I've check to make sure the gasket matches both parts correctly. The only thing I can figure is the mating surfaces are at different angles, but I don't know why. The heads are aluminum Trick Flow Twisted Wedge heads, and the intake is an aluminum TPIS Mini Ram II, neither of which have been machined at all.

Sorry for the long story. So, what can I try next time to make sure the intake doesn't leak? I was tempted to try silicone around the ports like used on the end rails, but wasn't sure if this was a good idea. Does anyone make a thick gasket for this situation? Any thoughts? Help!



68 SS Convertible
Yellow - (77 Corvette)
383 w/DFI Fuel Injection
on MiniRamII intake,
Trick Flow heads
Tremec 5 sp, 3.31 12bolt Posi
Guildstrand Mod
AGR 12:1 power steering
Bent short steering arms
Baer 13" front brakes (Couldn't find time to make bracket for CBB)
550# Hypercoils with Landrum height adjusters

[This message has been edited by 68SSConvt (edited 06-07-2002).]
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post #2 of 4 (permalink) Old Jun 7th, 02, 08:20 PM
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Join Date: May 2002
Location: netherlands/waddinxveen
Posts: 1,114
i think your heads are a little lower then the stock heads, so your intake doesnt match the heads!
if the heads are lower then they will be closer to eachother and making the intake too wide.
Try to find the exact difference between the stock heads and new heads, then grind the that off the intake outlets.

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post #3 of 4 (permalink) Old Jun 8th, 02, 03:15 AM
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Join Date: Apr 2001
Location: Out here
Posts: 111
Yepper I was successful in sealing the intake. Before you rip the thing apart again I would check a couple of things first.
1) The PCV. Not only was my intake leaking but I was drawing a lot of oil through the pcv line. The way my motor is set up the oil from number 6 intake rocker arm shoots right up in the baffle allowing to draw it through.

Second, if your valves were really oily it takes a little while to burn all of it off. take the car out and put some good hot miles on it.

I'm not sure which gaskets you used but I sure like the fel-pro ones. Especially the ones that have that blue stripe around the ports. Seems to seal very well. Also, ditch the cork end-gaskets and use a thick bead of black hi-temp RTV. Run the bead from one intake gasket to the other and let it set up for about 15 min.

If all else fails in getting the thing to seal, take some modeling clay and place it around the ports on your heads. Set the intake down and lightly torque some bolts in place. Remove the bolts and take a looksee to find where they aren't mating properly. Just becasue heads and intake are straight doesn't always mean the angle was machined right. I hope this helps. Let us know what you find. Scott

New skool is cool but a 509 and 4 speed still rulz
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post #4 of 4 (permalink) Old Jun 8th, 02, 03:26 AM
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Join Date: Feb 2002
Location: LR AR
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Obviously verify the port alignment. I like to scribe a line with a straight edge across the top and bottom of the ports front to back. Do this on both the heads and the intake. Run the scribed line out on to the outer surface paralell to the intake flow. You can see if the ports are lining up after the intake is bolted down that way.

You might look into a different port sides gasket. Try a Fel-Pro "Print-o-seal" that has beads of rubber around each port. That might help as well.

Avoid the use of the end rail gaskets and use a bead of silicone sealer. You should also verify the intake is not bottoming out on the front and rear rails before final assy. Run a feeler gauge side to side to verify clearance. This is a good start.

I had a brand new Holley 300-36 years ago that would not seal and after 3 tries, I went back to the Edelbrock Performer that fit fine before and just ran it. Just because it is new doesn't mean it is right.

Hope this helps.

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