[Murf]

I drove it probably 20 miles of sprited driving yesterday. When I pulled it in the garage there was a pretty good oil leak under it. I pulled the intake cause the valley pan looked like it started leaking.

I just now got underneath it & there’s a big puddle & I can see where it’s coming down from the top. If driving it with the pcv valve not hooked up to the carb caused this, I‘be got some big problems right?

Thanks!
Murf

[lust4speed]

PCV valve is a very minor player in purging the crankcase with large throttle openings and is only designed to suck up minimal vapor. Even in a normal engine the breather(s) are the main vents at heavy throttle. Figure when you floor the accelerator, vacuum drops to near zero and the PCV stops sucking.

[25stevem]

X2 with the above and hence the factory set up where a big tube goes from the center of one of the valve covers to the air cleaner housing since above the carb at high throttle opening’s there is more vacuum to be had.

When one installs a aftermarket air cleaner you want one that with punch outs on the underside and then you install the supplied plastic nipple that will allow the hook up of a hose to replace the tube.

[Murf]

Originally Posted by 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.

Hey Jay, I sent you a text.

Murf

[surfsama]

If you have a cam with excessive overlap it could create enough exhaust reversion to leave a film on the intake runners that looks like oil.

[68WarDog]

Originally Posted by surfsama

If you have a cam with excessive overlap it could create enough exhaust reversion to leave a film on the intake runners that looks like oil.

Can you explain how this happens? I always believed that during overlap, the exhaust track has negative pressure, pulling a % ( overlap dependant) of the intake charge into the exhaust tract. Or,have I got this backwards?

[Murf]

Well, I did a Half A$$ leak down test today.
Engine was cold, as I hadn’t put it together yet. All cylinders held between 92 lbs and 97 lbs. I could hear air in the intake port on all of them. Slight leakage in pcv hole on some but not all. So I don’t know what that tells me.for sure. The heads will need attention but I’m putting it back together for now.

I’m sure the cold vs warm engine wouldn’t make any difference on the valves but as a general rule of thumb, would a warm engine test tend to have better ring seal? It would be nice if just head work would get me by.

I don’t know if any of this has anything to do with the smoking & sudden major oil leak. I think the valley pan was where most of the oil came from. Maybe that & the oil smoke in exhaust are unrelated.
Should have it going Monday. I hope something is different! ��

Murf