Got a lot of attention in my Waggy yesterday

[deckside]

Was the envy of the Bales parking lot... Strapped a Christmas tree to the top of my rig, put my adorable 7 year old daughter in her childs seat then went to crank it over my 1980 Waggy with a 360 with eddlebrock 4bbl carb. Sounded to me like a small explosion and then smoke poured out if my hood.Lots of heads whipping around and raised eybrows from the Christmas tree shopping crowd. Opened the hood and noted the oil fill tube cap was off and that looked to be the only thing amiss. Cranked it back up with no issue and drove home. Ideling a bit rough and still smells like oil burning (which is the same as.last week which looked to me to be drips hitting my exhaust). Any thing to cause alarm?

[gpcl16]

Sounds like a normal Jeep to me

[72jeeperjoe]

Is it still running off, any bogging or hesitation or back fire through the carburetor? It could have been the timing chain jumping a tooth which would contribute to all those symptoms. It could have been a carburetor issue that just intermittently popped up if it seems better now. Hope that helps!

[deckside]

Will try to diagnose the timing chain but is not running that bad so might just need a little tune up...that's what I'm hoping anyways.

[72jeeperjoe]

That?s the hope! If it was timing chain it would be real rough.

[nograin]

From your description, it sounds like fuel, or fuel vapors, in the oil pan and connected areas (everything but inside the combustion chambers etc).

Backfire through the carb would be in the aircleaner and I can't think of how it would make it through to the breather cap.

[72jeeperjoe]

Will try to diagnose the timing chain but is not running that bad so might just need a little tune up...that's what I'm hoping anyways.

The somewhat rough idle may just be a fouled plug, doesn?t hurt to change them out.

[Rod2]

Odd that you should post that message; I left the filler/breather cap off after adding oil, drove about 15 miles with rough running, stumbling engine, poor performance that wasn't apparent at the last outing. Does open filler tube have that kind of affect on engine performance?

[Kenall]

[nograin]

... I left the filler/breather cap off after adding oil, drove about 15 miles with rough running, stumbling engine, poor performance that wasn't apparent at the last outing. Does open filler tube have that kind of affect on engine performance?

No it shouldn't.
That's how it was before the late 60s.
PCV came in early 60s, replacing the draft tube and other methods of evacuting crank case vapors. But the vent/breathers remained open to atmosphere for several more years.

Something else is up. Did reinstalling the cap fix it?

[deckside]

Happened again today when I was installing hei. Was having trouble turning over and I was pumping the accelerator pedal then poof/ bang oil cap is off smoke everywhere. This time saw smoke coming out of passenger side valve cover as well. Gave it a few minutes and turned the hei a bit, turned over no issue.

[FSJunkie]

It sounds like an intake backfire is traveling through the PCV system and igniting the fuel vapors in the crankcase. The PCV valve is supposed to seal like a check valve to prevent this from happening. In other words: check the PCV valve.

[deckside]

Okay, will install new PCV. Reckon I ought to replace the valve cover gasket as well since smoke was able to pass through?