burning oil, strange fix

[Joe_Van_Duno]

Well hopefully I don't jinx myself by telling everyone my issue and what I think was my fix.
Just some quick background info, I bought an 89 Shadow 2.5 turbo auto for a fun driver and it had a blown turbo only making 7 psi and smoking oil like crazy. So I picked up a used garret turbo, intercooler and radiator from a shelby Z and I've been working on swapping them out for the last couple of weekends.


Yesterday I finally got the shadow running and driving (plates and insurance) but it was still POURING out blue smoke. I was hoping it was residue in the exhaust from the blown mitsu turbo. I kept checking the plugs and didn't see any signs of burning oil which was supporting my theory on residue oil. So I took it for a drive up to my dads house, about 40 miles, hoping to "blow out" all the old oil. Well sure enough the car was still smoking badly and after checking the oil I found that I burned through a 1/4 of a quart. So just to expand that a little the car was burning 1 quart every 160 miles....not good.


So I topped off the oil and drove back home. I pulled the plugs last night and found cylinder 4 had signs of burnt oil on it. After talking with JT (thanks again for all the tech support) we determined that a compression check was necessary and if compression is good, then I needed to inspect the valve seals.


I checked compression this morning and found to be 125 across the board. So I pulled the valve cover and low and behold one valve seal was sitting about 1/4 inch off the "base" of the valve. I used a screwdriver and a pick to push the seal back in place, re-assembled the car and sure enough it's no longer a fog machine!!!!


Best I can figure I caused this problem when replacing the turbo. I had the cylinder head sitting on my work bench tilted on about a 45 degree angle with the combustion chamber facing up. I'm thinking the seal slipped down while sitting upside down for 2 weeks.


Thought I'd share my experience just in case someone else runs into the same issue, but I'm pretty sure it's going to be a one time issue.

[turbovanman²]

FYI, you can have good compression and bad oil rings as a compression test will not diagnose that.

I would check to make sure the valve guide hasn't dropped, common problem and that will cause the oil seal to come off.

[zin]

Simon has a good point, those seals see many "Gs" when the valves are opening and closing, it is unlikely that they would just slip down sitting on the bench, in fact, I'd almost guarantee it.

The guide deal though might be why you had smoke in the first place... That other turbo may be fine!

A leak-down test will tell you where the leakage is, though you seem to have a bead on what the problem is.. Definitely worth pulling the VC to see for sure, otherwise the problem will come back down the road.

Mike

[OmniLuvr]

make sure the valve guide hasn't dropped, common problem and that will cause the oil seal to come off.

happend to me, but the guide actually lifted instead of dropped, resulting in the same problem, it was a bummer...

[shackwrrr]

Sounds like a pcv issue that you unknowingly fixed when you removed the valve cover.

[Joe_Van_Duno]

Thanks for the tips guys, I'm not to concerned with it. I picked it up just for something fun to play around it. If I have to put any serious type of money into repairs I'd just part the car out. So far swapping turbo and adding intercooler/radiator setup I'm still under $1000 into the car including plates and title transfer.

I doubt the original turbo was still good. The car wouldn't build more than 5psi when I got it. I checked vacuum lines, didn't see any issues so I just replaced all the lines anyway. Still had very low boost. I decided to pull the vacuum line off the wategate and then it built about 7psi. When I pulled back into my driveway it started smoking at idle. Even if there was something else besides turbo, doesn't really matter, I have a nice garret on there now that's boosting very well :eyebrows:

I thought the seal sliding up was strange too, but it was the only theory I could come up with. The seal was definitely moved up on the valve, and when I slide it back down it almost felt like it slipped into a notch or into a groove. So far I've driven the car about 15 miles (hard driving too) and no smoke. So I'll keep my fingers crossed.

[RoadWarrior222]

I guess it's possible the valve seat wasn't correctly seated in the first place.