Thread: Intake runners sucking oil?

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Hello everyone.

I have a fresh 383 in my 38 chevy truck, complete with 2.02/ 1.6 heads. The heads also have positive oil seals on them. Everything is fresh.
I just finished re-installing my intake with a fresh set of Fel pro gaskets. I noticed the old gaskets had some evidence of oil around all the intake ports. This engine has been a real bear to tune.
At first I thought of the the PCV pulling oil ( which it still may be doing ), but the evidence is pointing to the intake sucking the oil. Could the intake be warped? It would have to get awful hot to do that right? It's a vic jr. intake in case anyone needs to know.

The only thing I did different this time was to only put a thin layer of "gasgachinc" on the head side of the gaskets leaving the "beaded" side of the gaskets dry against the manifold side. I hope after leaving it to cure overnite, that the smoke out the back will end. Any advice about this issue? Thanks to all in advance.

Jerry

Set the intake on the engine without the gaskets and see if the distances look normal....

On some iffy seals I would spray "Hitach" or "Ultra Copper" on the gasket and then tighten them down....

http://streetmachinesoftablerock.com...opic.php?t=350

Dutchhotrod, I just ripped apart a brand new 406 with less than 500 miles on it. My engine was doing the same thing but worse. Anyway, the motor was sucking oil through the PCV valve. The blower was soaked inside and the intake was walloring in oil. When I pulled the intake, each intake valve that was closed had about a tablespoon of oil in the port. Major bummer. Oh well, live and learn, it's only money!

~ a month ago I started my 403 the first time in almost a year.
Wow i finally noticed all the smoking, then I saw about a teaspoon of unburnt oil coming from an exhaust leak.

teriffically bummed, I just decided it needed a new engine after something happenned during the winter.

amazingly I restarted it a few days later and it ran FINE with NO OIL LEAK or SMOKE

))

Aluminum manifolds must be retightened regularly or they develop those problems. The aluminum expands and contracts with heat changes, more than the iron heads.

I think you may be right to blame the pcv, I had a simmiler problem and changed the pcv and it went away. are your valve covers baffled? try disconnecting the pcv and plug the vacuum line. Carlg

Yes, my valve covers are baffled and I did bypass the PCV for now. After running it, the plugs are all wet around the threads,and almost all of them are dry around the electrodes. Could this be residule run off in the heads?

My only other thought is to yank the manifold. When I dropped the motor and trans in, I did use a carb plate to lift the motoe into the engine bay. Could the weight caused the intake runners to get tweaked enough to cause the runners to seep oil from the galley? I don't mind yanking the manifold out, if I know it is the problem. Someone mentioned using modeling clay, which may tell what happened.

I had this happen once when some dummy (me) used RTV on the manifold gasket. The gasket slipped at the bottom of the center two ports on each side and sucked oil. The plugs were real oily. When I pulled the intake, it was easy to see that the gasked was oil stained and leaking.

If your heads have been milled or the block decked, the intake sits higher relative to the head ports so that might make the bottom part of the gasket leak. There isnt much compressed gasket area down there.

Did you use any sealer on the intake gaskets? Try them dry...easy to change.

Some manifolds are thinner than others, causing the bolts to bottom out before tightening up the manifold. Could be your problem.