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valve cover problem

539 Views 4 Replies 3 Participants Last post by  GeeAea
hello to all, thanks for all the help so far!!! I'm back with another problem. After the motor rebuild(4.2l, .030 over,,milled head,borla headr,carb,tfi,etc.)I put on a new valve cover from 4wd hardware.I noticed some blue smoke .I thought it might just be my rings seating or something so didn't realy worry about it. Now the motors broken in and still getting it. More on start up or if i let it idle for a few minutes. The guy at the machine shop says he's seen this before with aftermarket valve covers on this motor, that they don't have a baffle for the pcv system to bring it down to the bottom of the valve cover like the stock one. Has anyone else experienced this? any solutions, etc.. thanks again!! gman
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This was a common problem with the Cifford valve cover. I'm not sure if your's is the same valve cover marketed and vended by someone else.

Apparently they didn't take the time to install/test/perfect the baffle that prevents oil from getting sucked up into the draft created by the PCV valve. My 4.0 valve cover, IIRC, has a plate that extends the entire length of the valve cover ..with only a very slight opening along one edge (you almost can't see it). Any oil slung off the rockers (or just spaying around in there) strikes the plate and drops back down to the head.

If you just want to determine if this is the source of your oil smoke ...put a water seperator in line (like they use on compressed air) and see if it collects oil. I'm sure that you can adapt some type of small bottle ...but being on the suction side you have to seal it well so that you don't bleed manifold vacuum (think of it as a shop vac canister).
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