RED MX5

Is it possible that your mods to the PCV system have resulted in crank case pressure (particularly under boost) that is forcing oil past a seal?

I have yet to see any signs of excessive blowby, before or since the SC install. (IOW, no oil or excess vapors coming from the bypass-valve to the air filter.) Generally excessive blowby (enough to blow oil out to the air filter) points to other problems.

Asura

So you think the CranksVents most likely contributed to this?

gary_phd

Actually, the krankvents lower crank case pressure - the pcv/manifold krankvent prevents pressure/boost from entering the crank (one way into the manifold, with an oil catch can enroute).

Then, the second krankvent at the breather only allows air to escape...as well, I've got the remotely filtered with another catch can inline (no oil what so ever there). This setup lowers crankcase pressures, making a vacuum.

[QUOTE]I have yet to see any signs of excessive blowby, before or since the SC install. (IOW, no oil or excess vapors coming from the bypass-valve to the air filter.)

RED MX5

No, but if the crankcase vents were installed because there was excessive blowby, then there could be substantial pressure in the crankcase, and crankcase pressure can blow oil past seals. Combustion pressure is what causes blowby, not boost, but it might not reach critical levels until peak torque is approached, because that's when the combustion pressure is greatest.

Last year I had a disagreement about blowby related problems with our chief mechanic, because one of our Skylines had so much blowby that it could not be tuned properly without disconnecting the PCV system. A breather and catch can had been installed, but I objected that the blowby was still a problem. Since then the car has been through two clutches because of oil leaking past the rear seal, and now it is down because the oil became over-polluted with gasoline and didn't provide sufficient lubrication to prevent the front main bearing from melting. When the engine goes back together the problem (excessive blowby) will be corrected rather than bypassed, and we won't be wasting any more clutches or bearings. In general, if there is more blowby than the PCV system can hanldle then there is too much. Many (probably most) mechanics will work around the problem with vents and catch cans, but IMO that's just asking for trouble down the road.

Of course I have NO IDEA of whether this particular problem is related to blowby created crankcase pressure, but I do know that it sometimes causes oil leaks from odd places. Extra vents don't always relieve the pressure enough to prevent problems.

RED MX5

If one of the vents allows pressure to escape, and you're not seeing vapor coming out of it, then excessive blowby probably isn't what's causing the leak, but if the system isn't venting the pressure properly ...

Should be easy enough to check. If there is a negative pressure ("vacuum") then you should be able to feel air being drawn in through the oil fill hole. I'm just thinking that it would be shame to replace the supercharger seals only to have them blow out again because we overlooked a possible cause for the failure. I've seen far too many otherwise competent mechanics overlook or work around significant blowby problems.

gary_phd

I appreciate the input Red. Yes, after the car has ran, there is sucking in of air from the dipstick when I remove it.

I'll be going to Comptech this Friday to have them inspect the sc. Apparently, during the time I purchased my sc, there were a batch of sc's from Paxton that have shown similar issues as mine. The great thing is that they are familiar with the problems I noted. If all goes well, they will be replacing my sc the same day.

RED MX5

While you're at Comptech, see if they can give you a range of serial numbers for suspect Novi's. I'd like to know if this is something I might have to watch out for.

gary_phd

I'll make sure to ask them Friday...hope it's something they are willing to disclose. I'll update on this thread.

Kremlin

Update?

kyo

What did you find out? I think i might have the same problem.