I started burning a lot of oil last year. It was espoecially noticeable at the track. I had to add a quart after every session and people behind me said I was smoking on boost. The oil pan also started leaking. It leaks right over the crossover which is noticeable because the oil burns on the crossover causing smoke off the crossover. I just finished up compression and leakdown on a warm engine.

Compression:

#1- 130, #2 - 116, #3- 133, #4 - 135
They all popped up to mid 150's when I put a few drops of oil in the spark plug holes.

Leakdown:

#1 - 3%, #2 - 17%, #3- 7%, #4 - 9%

I could hear all the leakages out the oil filler tube. The car has 80k miles on it. I am wondering if this is a situation in which I definitely have to to a ring job or not. The reason I ask is I don't have a ton of time. I already deal with the looks and comments from my wife when i am under there getting ready for Drivers ED. If this is a situation that I am going to risk severe engine damage if I don't do anything about this then its a no brainer. I will do the rings and probably the rod bearings since the pan will be off if I don't have any choice and i will just have to deal with not driving it as much this year and probably almost no track time. I am not too concerned about street driving as I check the oil religeously. I am concerned about the track and what may happen. What do you think?

 

I have almost the exact same values in mine, and I did a ring job last year. I'm suspecting a problem with the ring installation or out-of-round bores. Hard to say for sure, but for street driving it probably won't do much damage, so long as you keep oil levels in check. You will be down on power which given all your mods, may irritate you somewhat. I dyno'd mine recently and found I was down 20-30 hp from where I expected, and I expect it is from my poor compression figures. One thing I did notice is that the crankcase will pressurize quite a bit, especially under boost with that 17% leakdown result. You're probably getting lots of oil blown through the crankcase vent and into the intake. I put a catch can in mine to deal with that. Not a remedy for the root-cause, but keeps it in check until I pull the motor again and fix its problems.

Your track use might lead to unseating a front or rear crank seal if crankcase pressures are high for sustained periods. That could be explaining your oil leaks.

If I was you, I would fix it before any more track use, but use it on the street until I had time to tear into it and fix it right.

 

Street i wont worry, i'll just check the oil. track i wouldnt recommend it. compression isnt looking to good usually the rule of thumb is 5 psi with in each other. Now leak down iam not too sure so i am to keep my mouth shut. Well i getting my comp and leak down test today. Cant wait for the results. I'll post mine up.

 

Sorry if this is a little off topic but what are good compression #'s for our cars?

 

Hey Jordan, Brady bought a leakdown and ion tester recently. We will see how healthy your motor is but I suspect yours is fine.

 

145psi-150psi @ normal operating tempreature.

 

Just wondering if there are any more opinions out there from those who know. Should my car even be running OK or be able to start at all in 9 degree weather in my unheated garage with 17% leakdown on one cylinder?

 

Yep, it will start and run with 100% leakdown on one cylinder.
I installed some rings up-side down, and as soon as the cylinder hit ~150-200psi (during combustion), it was like a big air valve, so essentially I was carrying one dead cylinder, and it still ran pretty darn well. It was slow, but still.
Given your altitude, good compression numbers would be in the 145-150psi range. After a rebuild, and 6000 miles on my rings, I did a compression test (keep in mind I am a couple thousand feet higher than you), and got 142-145psi on all 4.
17% leakdown is enough to worry, but what should really be on your mind is why.
I don't think a simple re-ring is in order here. If it was, you would also expect all 4 cylinders to be pretty comparable in both compression and leakdown #'s. You might want to find out just what happened to that cylinder.

 

I think I will retest it again this weekend just for the fun of it. I did #2 last because its last in the firing order. I spent a good amount of time doing the test so maybe it cooled down enough to give the poor results. Then again maybe not since the compression was previously low on #2. I think at a minimum I probably should pull the head to see if it could be HG related as mentioned to me by someone on here since it has to come off to do rings.

 

My 89 turbo had almost the EXACT numbers (same places too) when I bought mine and I was able to use these as a bargining point. The culprit turned out to be a slowly leaking head gasket that eventually showed itself as foam in the collant tank. I did not drive it much after that and when the head gasket was replaced I had a MILDLY warped head that required machining it down a tiny bit. Up till the foam in the expansion tank I had lots of people tell me don't worry about it. The car ran quite strong till the day I quite driving it. In fact a week before that I had hit 160 in the car just fine so it COULD (notice I said COULD) be a head gasket.

IPSC

 

I just put all the plugs back in and hooked everything up and warmed up the car. I just tested #2 and I got similar leakdown %'s as before (17) but I noticed it was coming both from the oil filler and the Jboot since I had the afm off. If i left the oil filler cap on it noticeably came from the jboot. When i had the oil filler cap off it came out of both spots. definitely pulling the head to check out the valves and to check the cylinder walls.

 

DOHHHH oh nooooo that sucks possibly valves?

IPSC

 

Not sure. I was thinking valves would be easier and less intrusive than the piston rings.

 

Probably carboned valves/seats. When I leak-down tested my N/A, I got horrible numbers in 2 cylinders. Now that I'm disassembling it, it turns out those 2 cylinders had badly fouled valves that wouldn't close all the way. If you hear hissing from the J-boot, that's good news at this point

 

Well, the oil/air separator has a hose that goes back to the j-boot, so especially if you leave the oil filler cap on, you will hear air flow past the rings going to the j-boot.

To check leakage for the intake valves, pull the intercooler tube leading to the intake and open the throttle body butterfly so you have a direct line to the intake valves. If there is leakage past an intake valve - you will hear it through the throttle body.