oil puke.. no I didn't drink it

[ScampMike]

what the frig happened!? took the car out yesterday, stomped on it pretty good a couple of times, ran great - lots of smiles in the miles... BUT when I got home it "dieseled" after I shut it off and then puked oil out in a big way - it actually made it through the hood opening and onto the fender. I haven't had time yet to get out there and try to figure out what is up but, I did pull the hood immediately and found the oil dip stick was up and no longer seated in it's tube.. So I'm fairly sure the dieseling is because the timing is a bit off (advanced) but what the hell with the oil puke?

 

[TrailBeast]

Are you sure the puking wasn't happening the whole time, and you just noticed it when you got home?
I have NEVER heard of one just suddenly puking on shutdown. (or even from dieseling)

Plugs being to hot of a range can cause "Run on" also, or any other hot spots in the cylinder.

 

[ScampMike]

no not sure at all.. kinda just looking for avenues to investigate.. could the added back pressure from the "legal" exhaust system be a culprit?

Are you sure the puking wasn't happening the whole time, and you just noticed it when you got home?
I have NEVER heard of one just suddenly puking on shutdown. (or even from dieseling)

Plugs being to hot of a range can cause "Run on" also, or any other hot spots in the cylinder.

 

[prorac1]

I would check the PCV system over. Sounds like crankcase pressure building up. Probably at higher RPM when you were gouging on it. A good functioning system for evacuating crankcase pressure is imperative. Espically when compression and cubes increases. JMHO. Eric L

 

[TrailBeast]

I would check the PCV system over. Sounds like crankcase pressure building up. Probably at higher RPM when you were gouging on it. A good functioning system for evacuating crankcase pressure is imperative. Espically when compression and cubes increases. JMHO. Eric L

X2
Especially if it's a newer motor and might not be broke in all the way.

I seriously doubt the exhaust is causing it.

 

[nm9stheham]

Dieseling is usually caused by the throttle being open too far at idle, along with hot combustion chambers. Timing has nothing to do directly with dieseling as the ignition is OFF when it happens. Tming's indirect contribution to dieseling is in its effect on engine temps: Retarded timing can make the engine run hotter and thus contribute to the tendency to diesel.

In the case of a PCV, if it malfunctions and hangs open at idle and allows too much draw at idle/high vacuum, then it can feed extra oil/air mixture into the intake (which will combust) and act like a more open throttle. I have to wonder if the PCV is hung wide open, and allowed a backfire as part of the dieseling back into the crankcase that puked the oil an dipstick out. (But this all assumes you HAVE a PCV valve! LOL)

 

[ScampMike]

well, it's got a race crankcase evac system (a breather on each valve cover connected to a tube on the header) instead of the PCV valve - I will certainly check that for blockages.. definitely going to recheck that timing too - wondering if I am off with that and have the carb adjusted up a little too much to compensate.. hummmmm

 

[nm9stheham]

Any backfires out of the exhaust when this happened? Just thinking (out loud) that it might have put a pressure pulse back up into the crankcase vai the EVAC system. I'd be checking the carb to make sure some raw gas is not getting out into the exhaust during the dieseling and exploding.

When you let off of the throttle, does the car idle down and give you good engine braking immediately? Or does the throttle seem to be hanging open a bit? Just checking for reasons that may point to a mildlly hung throttle... springs, bound throttle cable, etc...And too far open on the carb secondary stop may contribute to the dieseling.

 

[ScampMike]

huh - good stuff - she doesn't engine brake much at all --- I don't have to kick at the throttle but the car does travel on a bit. Anyway, out I go to clean up- booo hiss :banghead:...and investigate..

Any backfires out of the exhaust when this happened? Just thinking (out loud) that it might have put a pressure pulse back up into the crankcase vai the EVAC system. I'd be checking the carb to make sure some raw gas is not getting out into the exhaust during the dieseling and exploding.

When you let off of the throttle, does the car idle down and give you good engine braking immediately? Or does the throttle seem to be hanging open a bit? Just checking for reasons that may point to a mildlly hung throttle... springs, bound throttle cable, etc...And too far open on the carb secondary stop may contribute to the dieseling.

 

[TrailBeast]

An evac system connected to a header with a restricted/street exhaust could certainly do it.
Even with an open header system you have to be pretty picky about where in the system it is to get vacuum.

You (might) even be making the problem worse with a street legal exhaust system.

 

[nm9stheham]

An evac system connected to a header with a restricted/street exhaust could certainly do it.
Even with an open header system you have to be pretty picky about where in the system it is to get vacuum.

You (might) even be making the problem worse with a street legal exhaust system.

Points to monitoring the vacuum or lack there of on the EVAC tubes when running at various throttle positions.

 

[Inertia]

As mentioned, boost the timing, there are several threads on how to establish "initial timing" and then limiting total timing. That will allow you to close the throttle at idle, and prevent run-on. Your idle mixture screws might become more effective as well.

I'd take the 2 vent hoses off and plug them, take the oil filler cap off, start it up, and put your hand over the oil filler to feel how much pressure (blow-by) you have, rev it up a few times,, the pressure you feel is likely what blew the oil/dip-stick out.

I hope I'm wrong, regardless - hope it helps

 

[AJ/FormS]

huh - good stuff - she doesn't engine brake much at all --- I don't have to kick at the throttle but the car does travel on a bit. Anyway, out I go to clean up- booo hiss :banghead:...and investigate..

If you have an M/T, this, and the run-on,point to the throttle blades being open too far, in an effort to compensate for insufficient idle-timing, and/or a hung-open secondary.

With the header evacs, I found even just one, to be too powerful, on my street 360.It liked to pull oil right out the valve cover, and deposit it into the muffler, and it would come out the tailpipe.There was so much un-ending smoke,I though I blew the rings right into the pan. Took me a few minutes to figure out it was just the evacuator.So I changed the baffle system inside the VC and cleaned the breather, but it did it again, so I shelved it/them. The PCV system has always worked fine.

 

[Rapid Robert]

well, it's got a race crankcase evac system (a breather on each valve cover connected to a tube on the header)

most evac systems dont pull enough to do well on the street plus you ain't hooked up correct, you would want both header collectors ran to a T then connected up to ONE of the valve covers (for max pull) then a filtered breather on the other VC so you're pullin air in one side & down in the crankcase and around then up and out the other VC (like the PCV system does).

 

[ScampMike]

thanks all! Well, the oil was all the way down the pass. side of the car, so cleaning up meant a good warm water bath for one whole side and the windshield as well as the under hood mess (which I am not done with). Obviously this wasn't isolated to the driveway shut down diesel situation.. still going to explore the suggestions made here because it did diesel - gots me sum freakin werk 2 dew,,,