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Join Date: Dec 1969
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'75 2.0L PCV system "howling"

I finally hooked up the PCV system on my 75, got sick of black oil after 100 miles.

It isn't like the one on my '72 1.7L or DD's '73-'74 2.0L hose diagram. First off there are no breather pipes in the heads, and no flashback valve. Also, as far as I can tell, no PCV valve in the oil filler neck. I simply have a hose running from the 3/4" oil filler neck to a 1/2" nipple in the intake plenum after the throttle body.

At idle up to 1500 there is an anoying howl that must be an air leak somewhere, or is there something missing on my system?

Could someone with a working 75 2.0L PCV system please tell me what their's consists of?

TIA

Old 09-22-2000, 12:25 AM
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My '75 2.0 has the vent in the right head and a PCV valve in the filler housing. Unfortunately it was converted to carburation before I owned it, so I don't have any details as to where things went originally.

But for what I have come to know about PCV (Positive Crankcase Ventilation)systems, there has to be an intake (breather usually in the air filter box)and exhaust (PCV valve connected to a vacuum port). By definition, it would have to draw fresh filtered air in and exit the crankcase fumes into the induction system.

Maybe somewhere in the past your right head was swapped out for a left one. The left head is the same except the factory did not drill the bosses for the vent tube and CHT sensor. This happened to me when I lost a valve seat in the right head, and the replacement head didn't have those two places drilled. I drilled out the holes to match the head I was replacing.

The above is subject to theory and opinion, if someone else has a more exact answer I would disregard mine. Hope any of this was helpful.
Chris
Old 09-22-2000, 06:26 AM
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Actually, Chris, I think someone may have swapped out your right-side head. I don't think that the 75-76 motors have head vents--at least, Jim T's doesn't, and the two heads that were at the one machine shop I used didn't.

My speculation is that the air injection system somehow took over or eliminated the functioning of the head vents. But I'm not really sure how that would work...

I don't have access to a 75 2.0 to draw up. Sorry. You may have some luck looking at the 75 1.8 diagram...

--DD
Old 09-22-2000, 06:57 AM
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Thanks Dave, disclaimer proved worthwhile .

Old 09-22-2000, 10:08 AM
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