Oil in air cleaner

118,000 miles is a fair amount of wear on this engine. you didn't say what year, but if it's an original , unrebuilt engine, it's 30 - 40 years old, and that is as heavy a contributor to wear as run-time is. oil sitting in a sump is doing it's chemical-reaction thing for all that time. 118K is maybe half-life for an engine made in the 2000's, but not old Detroit (Kenosha) cast iron.

the advice here is all good, flush and run it. i suggest switching to a good synthetic oil, Mobil 1 15W-50, specifically 15W-50, has a ZDDP additive, the others don't. the bad side effects from stories of "synth oil loosens old crud" are largely false. if it's recently 'back on the road' you might do a couple of rapid (monthly) non-synth changes with  Seafoam or something first. get miles on it, get it hot on the highway, etc. synth oil is infinitely superior in every way.

oil's cheaper than engines.

The 66 and 67 232's have baffling inside the cover close to the back where the PCV valve goes in.

I have "cheated" the rebuild issue with many AMC 6 cyls with a variety of different catch cans and breathing apparatuses (apparatii?) but the best one I made sat on the valve cover and congealed the oil being blown up so it could drain back. and the regular vapors carried on to the breather box. The wisdom of putting the blown out oil back into the motor may be debatable but we weren't allowed any drips from our vehicles where I was working, so it worked for that.

purple72Gremlin wrote: Duane wrote: I looked at the underneath side of a new replacement Dorman valve cover, and there's no baffling of any kind. there needs to be some sort of baffling or other means of stopping liquid droplets flung from rockets etc from getting airborne and up the PCV and hose. but -- [QUOTE]but I still think your rings are gone and need replacing.  [...]  my 258 is stock and it doesn't put oil in the air cleaner.

i concur, again. blowby increases with age certainly, but actual liquid oil in the PCV system, beyond light condensation from blowby and cheap oil, is unusual in even an older motor. i've driven a lot of older sixes that visibly chug blow-by out the filler neck and they didn't soak the PCV system. but i agree, the lack of any baffle at all means a bad cover design and in 2014, there's no excuse for it.

120K miles *or*40 years is the reason it's worn. the way most American car consumer-drivers maintained their cars, plus expectations, the lower quality of lubricants, etc, means that most inexpensive cars of the 60's and 70's got lousy maintenance, especially in the 5 - 15 year old period when they're given to the buyers kids, sold off cheap, etc. cars at end-of-life get crap maintenance.

us enthusiasts don't do that, but the damage is done by the time we get them, and even the classic little old lady cars have bad seals and stuck rings. age is age.

I've been looking into the PCV valves further.

AMC had 2 PCV valves: a black valve and a silver valve. The black valve flows ~2 CFM at idle and ~4 CFM at full throttle. The silver valve flows ~2 CFM at all times.

All V8's through the 60's and 70's used the black valve, as did MOST I6's. Some, I6's, however, used the silver valve. There was no other difference between sixes that used the black or silver valve, so the valves should be directly interchangeable.

My 1977 232 calls for the silver valve and that's what I've been running. This valve doesn't have enough flow when the engine is pulling hard, and backflows oily vapors into the air cleaner along with blowing the oil out through the oil filler cap.

I swapped in the black valve and the problem is 100% solved. I also noticed the engine seems to have better power. I didn't even have to adjust the idle speed or mixture. Direct swap.

I recommend using the black valve. No oily air cleaner and a little more power.
-------------------------------------------------------

Black valve: AMC part # 3211538
Silver valve: AMC part # 3236675

Modern replacements for these valves are being made, but you won't find them by crossing the factory part numbers or going by year/make/model. There are 4 or 5 identical looking, but different flowing PCV valves that list for 1965-1977 AMC's, and only two of them actually work correctly.

Napa part # 2-9280 (stamped #2064) is equivalent to the OE black valve.

Napa part # 2-9523 (stamped #2016) is equivalent to the OE silver valve.