1FSTBRD
Registered User
With head gasket failures being as common as they are on these cars, I was wondering if the PCV system contributes to that. I'm not a huge expert on PCVs, but from what I know, their function is to vent the crankcase of too much pressure/ blowby, and also to reduce emissions, but one thing I had noticed on my 3.8 Mustang is that the upper and lower intake manifolds (and the runners going into the head) were just absolutely caked with sludgy, oily residue. This can't be a good thing in terms of air quality, because before I cleaned my intakes out in the 'Stang, I was getting more pinging, and higher octane wasn't solving it. It was driving me nuts. The factory PCV seems to be way too aggressive.
I don't have the experience of dismantling the SC engines like other people have, and the most I've done was take off the intake plenum/ supercharger/ intercooler/ IC tubing. But even after cleaning those things out, after taking them off again even a couple of weeks later, I'd noticed that the supercharger top and intercooler once again had a fair bit of oil in them. One wonders how much the oil and blowby reduces the effectiveness of the octane, especially under boost. What have people noticed with the lower intake and the ports going into the heads--do they get a fair bit oiled up with sludge? The intercooler seems to act as a bit of a filter (based on the oil that puddles up in the bottom), and the return plenum and return plenum area going into the intake manifold appeared to have a little bit of oil residue built up, but nothing major. The Mustang's intakes had a black tar, basically in them.
I had put an M/E Wagner dual adjustable PCV valve on the Mustang, along with an air/ oil separator, and after opening the intake back up, the system was almost totally clean (minus some black soot from the EGR valve). The PCV is pretty much disabled at WOT, but I still wonder if under cruise conditions and light boost, whether the PCV is pulling too much (too much blowby, reducing the octane level) or whether there's enough vacuum through to relieve the crankcase pressure enough under light boost (5-8 psi boost) when giving the car a little more acceleration, but still not wide open throttle and full boost. I'm kind of wondering if the factory PCV wasn't engineered for an N/A car, instead of a boosted car.
Thoughts?
I don't have the experience of dismantling the SC engines like other people have, and the most I've done was take off the intake plenum/ supercharger/ intercooler/ IC tubing. But even after cleaning those things out, after taking them off again even a couple of weeks later, I'd noticed that the supercharger top and intercooler once again had a fair bit of oil in them. One wonders how much the oil and blowby reduces the effectiveness of the octane, especially under boost. What have people noticed with the lower intake and the ports going into the heads--do they get a fair bit oiled up with sludge? The intercooler seems to act as a bit of a filter (based on the oil that puddles up in the bottom), and the return plenum and return plenum area going into the intake manifold appeared to have a little bit of oil residue built up, but nothing major. The Mustang's intakes had a black tar, basically in them.
I had put an M/E Wagner dual adjustable PCV valve on the Mustang, along with an air/ oil separator, and after opening the intake back up, the system was almost totally clean (minus some black soot from the EGR valve). The PCV is pretty much disabled at WOT, but I still wonder if under cruise conditions and light boost, whether the PCV is pulling too much (too much blowby, reducing the octane level) or whether there's enough vacuum through to relieve the crankcase pressure enough under light boost (5-8 psi boost) when giving the car a little more acceleration, but still not wide open throttle and full boost. I'm kind of wondering if the factory PCV wasn't engineered for an N/A car, instead of a boosted car.
Thoughts?
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