[Murf]

I just took the intake off the wife’s car. Most of the intake ports are oil coated. The intake gaskets seem pretty wet to me.
The valve covers don’t look to be leaking.

Iron heads & stock intake. Felpro 90205 gaskets put on over the winter. Installed them dry. Any ideas?

Valve seals or guides wouldn’t coat the intake tract of the heads would they?

Different gaskets, use sealer on the gaskets? I’ve never done that before.

Thanks
Murf

[25stevem]

If enough of the seals are letting oil get down them then yes, oil will be seen getting up into the intake runners and after you shut down a warmed up motor can be seen pooling on the back side of closed intake valves.
This is assuming you have leaky intake seals.


Even leaky enough exh valve seals can do this.

With either or a combo of both of these conditions to the point you have it occurring at you should be seeing blue oil smoke puffing at idle and you should be picking up a oil film on your finger if you run it around inside your tail pipe’s.

It could be you are sucking oil in from the intake gaskets as you questioned, but you would also at the same time be having a vacuum leak.

Has the way the motor idles changed lately?

You really need to find out what’s taking place here because oil getting into the chambers will greatly cut down on a fuels level of octane.

I have never used sealer on these type of F-P gaskets when everything mates up like it should other then a smear around the water cross over if I have separated it.

[25stevem]

What are you using for valve seals on this motor, the rubber O-rings that get captured in the bottom of the retainer, or a valve guide mounted seal?

If you use the rubber O-Ring you must then also use the stock metal splash shield on the top of the valve springs otherwise excess oil will get down all 16 of the valve guides.

[77 TRASHCAN]

Stock valley pan? With PCV valve in pan???

[Murf]

Thanks for the reply Steve! It has positive seals and all look to be in place. Yes, it’s got some smoke at idle. I thought it was fuel at first. I had Quadrajet Power build a Q jet for it last year. I chased a rich idle with it for a long time.

The idle screws wouldn’t effect idle & it was stinky. Today I slapped a spare Q jet on & idle cleaned up and the idle mixture screws will kill the motor now.

When I was test driving I noticed it still smoked but no longer smelled rich.

I saw I had a valley cover leak so I went after it. That’s when U noticed the oil in the intake ports.

Sorry bout the long winded post !

Murf

[25stevem]

Has this oil smoke condition been since the heads where worked for positive type seals?
If so they may be seals for 3/8” stem valves, not the needed 11/32” size.
I have seen this before and the motor just sits at idle puffing away once the oil starts to get warm and it gets all back thru the intake tract also.

[Jay S]

Are you running the stock PVC valve? Any oil in it’s line?

[Murf]

Jeff & Jay, I had a Butler pan with pvc valve. Same stock valve I always used. The pvc hose to the carb is very clean & dry.

Steve, this engine has been together for a long time. Not many miles on it though.

Is it possible it is sucking oil into the ports on the head side of the gasket? It kinda looks like that’s what’s going on but I’ve never seen that before.

Is there an type intake gasket that would seal better? Those Felpro’s don’t seem to compress very much. They are kinda thin & hard, although the show a pretty nice imprint on them.

Thanks guy’s!
Murf

["QUICK-SILVER"]

Is it oil or gas soaked soot from reversion during overlap?

Is it the same color as the oil in the pan?

Clay

[Murf]

Pretty sure it’s oil, Clay. Ports are nice & clean. Looks like somebody oiled down a vice or something.

Murf

[lust4speed]

I was with Jeff and Jay and was betting on a defective PCV valve or a PCV valve overwhelmed by bad baffling. Do all intake ports share about the same amount of coating and how does the plenum look?

[BDH79TA]

As for an intake gasket that's "softer", Edelbrock and FelPro both offer a version that will compress more and seal imperfections a little better. I've used the Edelbrock version. Seems to work pretty well. I'll have to find a link when I get time.

[BDH79TA]

Edelbrock gaskets

https://www.summitracing.com/parts/edl-7280

[Jay S]

I would expect a vacuum leak would show up also if the intake gasket was pulling oil in. If it is from ring seal it will be showing up on you spark plugs pretty quickly.

Cometic makes a compressible fiber gasket that is a little thicker than stock for irregular surfaces.

https://www.cometic.com/products/C5778-060


I have noticed the gas we have here in the Midwest can leave a brownish red resin in the intake ports that resemble’s oil. Not sure what exactly is in the gas that causes it, may from the MTBE used in our fuel here. The left over resin really shows up if it runs running rich.

[Half-Inch Stud]

Couple thoughts;

All ya need is 1 positive seal riding up on the valvestem to get oil in. Valvecover gasket leak onto intake flange for oil ingress sounds good but kinda rare.

Foul Smell at idle sounds like lean idle. Rich smell sounds like float level too high or compromized needle&seal.

While you are there, try a compression test, write down the results, if a weak CYL (or pair) is seen the re-torque the. headbolts. And do another compresion test a year later.

[chuckies76ta]

I had the same issue. Was my intake valve seals. They moved off the guides. Replaced with new ones now ok. Make sure to clean the guide if installing new seals.

[Murf]

Thanks for all the replies everyone. IDK what’s going on. The runners of the intake are kinda oily but the pic hose seemed very clean on the inside.

I think I ran the car without the pcv hooked up. I had been fooling around checking for vacuum leaks & had plugged it at the carb.

Is it possible that I have excessive blow by and having the pcv unhooked made enough difference for it to push oil out?

I think it’s going to have to go back together for now. Wife says summer is drivin time.

I’m gonna get a comp tester & leak down tester & see what I find out later.

Thanks again!
Murf

[77 TRASHCAN]

Plugging off the PCV would be a way to check to make its not the problem. I assume you have a breather, somewhere. A PCV system has to have a breather to pull fresh air into the crankcase, so the dirty crankcase vapors can be pulled into the engine to burn. ALl this helps keep the oil cleaner.

[racegto65]

Try to look down the runner at the back side of the intake valves. If any or all are oily/wet then I would say there is oil being pulled in from the guides/seals. Pontiac intake gaskets aren't close to anywhere to suck oil. If the positive seals were installed incorrectly the retainers could contact them causing them to not seal. Look at the tops of the seals for any damage.

[Murf]

That’s what I was wondering. I didn’t think there was anyplace to pull oil from, unless maybe leaking valve cover oil setting on the top of the intake gasket.
Anyhow the intake manifold does look kinda wet but the pcv hose seems pretty dry. I have a few pics.