Help! Crankcase Overpressure

[Frozen240]

I got my Nsport kit up and running the other day and everything seemed to be fine, good A/F ratio, low EGT, not overboosting, and good oil pressure. I drove it for a couple of miles and it seemed great, I got on the gas to see what kinda boost it was going to get and I think it got up to 5-6 psi. Just after that it started billowing blue smoke. I thought something was on fire but thankfully wasn't. I let the car sit for a while and then fired it back up and it seemed to run fine. Drove it for a two minutes and it started smoking again. Wasn't sure WTF happenned so today I checked the compression and it tested 160, 155, 160, 160. The turbo did not have any shaft play nor was there any oil in the inlet piping. I fired it up again and it started to smoke after only a minute of idling. I took off the oil cap and yep, there was definitely pressure there. I replaced my pcv valve when I was put my turbo in, so I can't see that being the problem as I checked it to make sure it worked before I put it in. That was a PITA. I'm running my wastegate signal from my i/c pipe just before the TB, my BOV,FPR, and boost gauge signal are all tapped off the stock fuel pressure regulator. On the Nsport cold air intake pipe there are three connections to make; one is for the crankcase breather, the other connects to a 1/2" pipe beside the TB, but I'm not sure what the last on is for. It has a 1/4' fitting. What am I supposed to run there? Should it be a vacuum signal or an atmospheric signal? Any ideas what is causing my crankcase to pressure up?

[C-Kwik]

Where on the turbo piping did you connect the crankcase breather tube? It should be before the turbo. If it's afte the turbo, that's the only way I see pressure building in the crankcase.

Pull your sparkplugs to check and see if the oil is burning in your combustion chamber. There wil be an oily residue on the plug electrodes. If there is, with your compression numbers being fine, I'd suspect oil is being introduced before the combustion chamber. Perhaps leaky intake valve stem seals.

[Frozen240]

The breather is connected to the inlet of the turbo. When I pulled the plugs they looked fine, brownish with no oily residue.

[Frozen240]

I changed oils to Mobil 1 synthetic, this probably wasn't a wise thing to do since my engine is not use to it. I switched to a regular conventional oil and it does not burn any oil at start-up or idle. I have not been able to duplicate the pressure in the crankcase. No ideas there. I am however still smoking up a storm like Cheech & Chong. I think I'm blowing oil out of the turbine, it doesn't smoke at idle but rev it up and it billows out. Could I have too much oil going to the turbo and in need of a feed restrictor? How do I know how much is enough oil? If my drain into the pan was too low could I have oil backing up and be causing the oil to blow out the turbo? I've got 25psi oil press at idle and 65-70 @ 3000rpm.

[Def]

The seals in your turbo could be bad.

I was behind an FD3S (3rd gen RX7) at the track a while back and that thing would billow out an AMAZING amount of blue smoke on our warm up lap. I couldn't pass, so me and my instructor just had to pass the warm up time making rotary jokes the whole lap.

That's the only thing I can think of for the smoking, not sure on pressurizing the crankcase.

I'd suggest a leakdown, as you can still get decent compression numbers on a hot engine, but still have enough leakdown to slightly pressurize the crankcase.

BTW - how do you know for sure it is pressurizing the 'case? I assume you opened up the oil cap at idle where the turbo isn't making any boost? It shouldn't stay pressurized with a properly working PCV should it?

[andrave]

it COULD be bad seals, but if your return line was blocked or you are flowing more oil to the turbo than the return line can flow, its gonna back up and smoke anyway.double, triple check those lines, especially your return line. Does it have a straight shot with no kinks to the oil pan? is the line kicked, crimped, horizontal, too thin, anything that could be leading to this?

[Frozen240]

Here's a couple of pics of my oil pan tap and my drain line. The drain line does not have any kinks or flat spots, the photo maybe a little deceiving. I have a 90 going into the pan and a bung welded on the pan as high up as I could get it.

[Frozen240]

Oil pan tap.

[huguetpj]

Your return line seems ok. What about your feed line? What size line are u using?

[C-Kwik]

I changed oils to Mobil 1 synthetic, this probably wasn't a wise thing to do since my engine is not use to it. I switched to a regular conventional oil and it does not burn any oil at start-up or idle. I have not been able to duplicate the pressure in the crankcase. No ideas there. I am however still smoking up a storm like Cheech & Chong. I think I'm blowing oil out of the turbine, it doesn't smoke at idle but rev it up and it billows out. Could I have too much oil going to the turbo and in need of a feed restrictor? How do I know how much is enough oil? If my drain into the pan was too low could I have oil backing up and be causing the oil to blow out the turbo? I've got 25psi oil press at idle and 65-70 @ 3000rpm.

I doubt the synthetic oil is the problem. And if the hoses are connected correctly, you should not be getting any pressure in the crankcase.

Did you use the oil feed line that NSport provided? If so, I would doubt that is an issue. But just in case, do you know what size that line is? Secondly, you mentioned your oil pressure. Is that at the block or at the turbo? I assume the drain line is also the one NSport provided? How big is it?

[Frozen240]

I disconnected the turbo drain line and ran the motor for a little bit and I had oil circulating. I took the turbo off and the oil drain line. In the drain line I can see some of the rubber inside of the stainless line has been pushed inwards from the fitting. At this point I'm thinking this could be the root of the problem. It is causing a restriction in flow and the oil is backing up. There was not a trace of oil in the exhaust manifold and in the down pipe there was a lot of oil residue. I could even see oil sitting in the exhaust turbine. Can I take the turbo apart and visually inspect the seals to see if they are still good? The oil pressure is taken at the block where I teed off for the oil feed. The oil lines in use are from Nsport, I don't know the sizes but I would guess that the drain is 3/4".

[Projex240]

Turbo shaft seals---the cause--there could be many causes. I am thinking that too muhc pressure got built up in the return line. I could be some debris in the return line causing it to back up.

But if there if no oil in the manifold, but in the downpipe--htere is deifnately oil getting past the shaft seals.

If this kit is new--send it back to nsport(the turbo i mean) to be looked at.

[Frozen240]

I got a new oil return line made, bolted everything up and fired it up. Magic! It took a couple of minutes to burn off the oil residue but it is no longer burning oil. Will there be any permanent damage to the seals?

[C-Kwik]

it should be fine.