Got the car running finally

[Mikez73]

It's definitely coming from the crankcase. I have no PCV. I have a couple of those little K&N filters in the garage but I'm not sure what the purpose one would serve in that location.

Edited July 14, 2010 by Mikez73
clarity

[TBone028]

If it is indeed the crankcase vent, then it should be on the bottom left of the engine block on the picture you posted above. The purpose of those little breather filters is to look pretty and get dirty really quickly with blow-by gas from the crankcase! If you are annoyed or tired of seeing those little wisps of smoke, you can run the hose from your crankcase to an oil-catch can. Think of it as another shiny part to match your polished valve cover, intake manifold, and heat shield.

And in case you didnt already know, in a stock engine (at least in a 240Z/260Z, I'm not familiar with the emissions plumbing in a 280Z) the crankcase hose attaches to the PCV valve on the intake manifold, where vacuum is used to help pull the blow-by gas from the crankcase into the combustion chamber to get burned off. Also, the valve cover vent would normally suck clean air to help flow through the crankcase in most light throttle conditions. I see your valve cover vent is routed somewhere with a hose. There should be a filter on the end of that hose. In some engines with excessive blow-by (sadly like mine) blow-by gas comes out of both the crankcase and valve cover vent in all conditions. Most people that put those little breather filters complain about them getting dirty/clogged very quickly with the oil/water/gas that is in blow-by gas. Some people choose to run an oil-catch can instead of venting the blow-by gas directly to atmosphere. It helps keep the engine bay cleaner, and I think some race classes require them.

On my stroker, I have excessive blow-by so I have blow-by gas coming out of both my crankcase and valve cover vent. In my set-up, I'm running the crankcase to a PCV valve on my intake manifold (I'm running SU's with SM needles), and have my valve cover vent fitted with a breather filter. I'm looking into an oil-catch can set-up. Using a homemade oil catch can, after 20 miles of driving I had about 1.5 ounces of blow-by mixture at the bottom of my catch-can! I would rather not have that going back into my combustion chamber! I didnt like the way it looked though and I went back to the set-up I just described.

Edited July 15, 2010 by TBone028