Crankcase pressure

[bark]

Has anyone had to relieve any crankcase pressure to stop unwanted oil leaks when turbo'ing their car?

At the moment I am just using the OEM relief port on the rocker cover but I reckon I will need to drill this out to a larger diameter and also add another relief port?? I am running 16psi. Car has a fully rebuilt engine so there are no 'normal wear and tear' leaks from stuffed gaskets etc...

Any thoughts??

[GS]

I could be going down the wrong track here, but i think the issue is that the PCV tube from the inlet manifold to the crankcase should have a valve that prevents the crankcase pressurising. The OEM valve doesnt cope with the increased pressure of FI and blows/collapses. Apparently the solution is the PCV tube from the Familia GTX??

Havent done this myself though...

[bark]

GS, I had read that on some forums but I couldn't understand why it would help as my "logic" would be wouldn't the turbo pcv valve only hold more pressure in?? Also I don't think I had come across that on any turbo'd cars here on this forum - again I was thinking well if this is an issue surely a few of us have done this mod??

But I have an open mind, I just need 'persuading' with the logic!

[GS]

Likewise, i briefly read about it on other forums 2-3 years ago, so im hazy on the detail. My understanding was that the PCV valve limited pressure from the inlet manifold into the crankcase, not out of it. In theory the crankcase shouldnt be pressurised. So your issue isnt so much relieving crankcase pressure, its avoiding it in the first place.

Or i could be completely wrong and talking bollocks

[CT]

Good luck is all I can say. Every single hipo MX5 engine I've owned has suffered with this issue and I have never found anything that really works. I have previously modified rocker covers with 3/4 inch breather ports, baffled and non baffled, big tanks, small hoses, large hoses, vacuum assistance from the intake, plumbback via the SE catch tank.......

I now run a small pump off my catch tank and a pushbutton on my dash to drain the catch tank back to the sump......

[Juffa]

I'm running a low level of boost, but decided to put a GTX PCV in as some extra insurance. This was after reading about/seeing damage on the miataturbo.net forum that was thought to have been caused by over pressurising the crankcase.

The part number is E301-13-890A. Cost is under $15.

J

[spikey]

Is that from Mazda?

[Juffa]

Is that from Mazda?

If you are referring to the part number above, then yes it is a Mazda part. The number came from a post on turbomiata.net. I took it to my dealer of choice and they handed over said part.

J

[CT]

I've got the GTX PCV too -didn't help me at all. On a road engine, as the revs used are usually pretty low, ie not redlining every geachange, it should be enough. On the racers engine, it doesn't seem to make any difference.

[bark]

Just an update, it "appears" that either the cam angle sensor o-ring or the rocker cover gasket are leaking. I am going to replace both items with OEM parts and see if this fixes things. Will keep you posted on results...