[jhein]

So I finally got around to doing this. Wasn't having any problems, just curious and to get a baseline too. I got worried when I pulled the plugs because #3 and #2 were both oil fouled. Then I realized those are the 2 cylinders that get the PCV gasses. Still seems like this might be excessive. Maybe I need one of those adjustable PCV valves? The first picture is Cyl 1,3,5,7. The second pic is 2,4,6,8.





The compression readings were:

1 - 176
3 - 177
5 - 175
7 - 176

2- -173
4 - 175
6 - 175
8 - 175

[Schurkey]

Originally Posted by jhein

#3 and #2 were both oil fouled. Then I realized those are the 2 cylinders that get the PCV gasses.

How do you have the PCV system routed? What intake manifold? What engine?

Most OEM systems attempt to divide PCV fumes as evenly as practical among all the cylinders, typically by splitting the fumes into both the upper and lower plenum, in the primary-throttle air stream. If only two cylinders are getting the PCV fumes, something in the plumbing needs to change.

Is the PCV system appropriately baffled so that oil mist isn't drawn in? Correct PCV valve? Engine does not have excessive blow-by?

[jhein]

Originally Posted by Schurkey

How do you have the PCV system routed? What intake manifold? What engine?

Most OEM systems attempt to divide PCV fumes as evenly as practical among all the cylinders, typically by splitting the fumes into both the upper and lower plenum, in the primary-throttle air stream. If only two cylinders are getting the PCV fumes, something in the plumbing needs to change.

Is the PCV system appropriately baffled so that oil mist isn't drawn in? Correct PCV valve? Engine does not have excessive blow-by?

I have a stock intake and factory style PCV system. I do have a Tomahawk valley pan, don't know if that matters. Picture below. Engine specs in my sig. I'll have to check on the proper PCV valve specs.

[Schurkey]

The fitting in the intake manifold should be extra-long, with orifices allowing the fumes into both the upper runner, and the lower runner.

Maybe you have the wrong fitting. Pull it out for cleaning and inspection.

[jhein]

Originally Posted by Schurkey

The fitting in the intake manifold should be extra-long, with orifices allowing the fumes into both the upper runner, and the lower runner.

Maybe you have the wrong fitting. Pull it out for cleaning and inspection.

Yes, I see that Ames sells two versions of that fitting. A short one and the corect long one. My #1 and #4 plugs are totally clean so maybe I have the wrong fitting or it's clogged (seems unlikely). I know it may decrease with a correct fitting but does that seem like an excessive amount of oil on those plugs?

[Schurkey]

How old are they? How many miles? How do you drive? Is there excessive blow-by? Does the engine have oil-consumption problems? Is there sufficient baffling of the PCV valve?

You're concerned based on PCV issues, but it could also be failing valve stem seals on those two cylinders; or scored cylinder walls that just happen to be near the PCV inlet fitting.

[jhein]

Originally Posted by Schurkey

How old are they? How many miles? How do you drive? Is there excessive blow-by? Does the engine have oil-consumption problems? Is there sufficient baffling of the PCV valve?

You're concerned based on PCV issues, but it could also be failing valve stem seals on those two cylinders; or scored cylinder walls that just happen to be near the PCV inlet fitting.

The plugs are about a year old. Approximately 2500 miles. My driving is a bit spirited. No blow by or oil consumption that I've detected, but it's a new motor and the cranking compression seems pretty good. Don't know about PCV baffling.

I know there are many things that can cause oil fouling besides the PCV system but I'd like to rule out simple things first.

[jhein]

Just a little follow up. First, I forgot to do my compression test warm. So my test was basically 175 across the board cold.

As for the oil fouled plugs, I verified that I have the correct deep fitting in the intake. I'm wondering if the problem I found with my distributor rotor could have resulted in less-than-optimal spark resulting in fouling of those two plugs? Maybe that's a stretch, I don't know. Anyway, I'm putting in a new cap and rotor and a new set of plugs. So I'll run that for a bit and then check the plugs again.

[PunchT37]

Have had trouble with cheap pcv valves in the past. Fresh air for the pcv system in good shape?

[jhein]

Originally Posted by PunchT37

Have had trouble with cheap pcv valves in the past. Fresh air for the pcv system in good shape?

I have a stock crankcase vent system. The valley pan PCV to the intake and the valve cover vent to the air cleaner. Where does the fresh air come from?

[PunchT37]

Originally Posted by jhein

I have a stock crankcase vent system. The valley pan PCV to the intake and the valve cover vent to the air cleaner. Where does the fresh air come from?

The air cleaner in your case. Filtered air needs to enter the crankcase to replace the air being sucked out by the throttled 3/8 vac line to the intake.