geo Posted May 2, 2007 Report Share Posted May 2, 2007 My 89 SW8 was leaking oil from the turbocharger, so I decided to bring it in to the local mechanic to get the turbo rebuilt, since my STX is under reconstruction in the garage and there is only so much I can do at once. I picked up the car after the turbo R&R and it was leaking oil from the head gasket area. I brought it back and they said it needs a new head gasket, $800 more. I took the car back home and discovered that there are exhaust gases coming out of the oil filler tube. Sounds to me like they had a problem with the wastegate, overboosted on a test run and blew a hole in one of my pistons. Does anyone know of anything else that could cause exhaust gases in the oil? Usually when the head cracks, exhaust leaks to the coolant not the oil, right? BTW, the valves were done and the head was welded before I purchased the car from George Bostic. Thanks in advance for your help. Quote Link to comment Share on other sites More sharing options...
Guest adegnes Posted May 3, 2007 Report Share Posted May 3, 2007 My 89 SW8 was leaking oil from the turbocharger, so I decided to bring it in to the local mechanic to get the turbo rebuilt, since my STX is under reconstruction in the garage and there is only so much I can do at once. I picked up the car after the turbo R&R and it was leaking oil from the head gasket area. I brought it back and they said it needs a new head gasket, $800 more. I took the car back home and discovered that there are exhaust gases coming out of the oil filler tube. Sounds to me like they had a problem with the wastegate, overboosted on a test run and blew a hole in one of my pistons. Does anyone know of anything else that could cause exhaust gases in the oil? Usually when the head cracks, exhaust leaks to the coolant not the oil, right? BTW, the valves were done and the head was welded before I purchased the car from George Bostic. Thanks in advance for your help. I your piston rings are worn out, you get a leak to the bottom of the engine. Does it spit oil out of the measuring tube, if you run the engine without the "measure stick"? how does the engine run? if you have a hole in a piston, it should perform pretty lousy... Quote Link to comment Share on other sites More sharing options...
geo Posted May 3, 2007 Author Report Share Posted May 3, 2007 It doesn't run terribly, but not as good as before. Oil does NOT spit out the dipstick. You can hear the exhaust when you take off the oil filler cap though. Thanks for replying. Quote Link to comment Share on other sites More sharing options...
Bean Posted May 4, 2007 Report Share Posted May 4, 2007 If you have a holed piston - you lose that cylinder completely. So if your car is running on all 4 cylinders, then the piston is fine. What hear and feel is just blow by (leakage past the rings), and unless this is a minty LOW mile motor - it's par for the course. I'd suspect fouled plugs and a good tune up is needed to restore it's previous performence. If the mechanics that did the work didn't do that after all that work they did, then I wouldn't trust them to get it back into shape. Find a good mechanic to do a compression test, and if possible with some experience to properly tune it and it'd probably be fine. Rabin Quote Link to comment Share on other sites More sharing options...
geo Posted May 4, 2007 Author Report Share Posted May 4, 2007 I just put new plugs in it before I brought it to them. The old ones were not that bad, no oil at all, even with 30K on them. The engine has 170k on it and it had the head welded and the valves done at 116K. I can do a compression test myself, which I will do tomorrow. Do you still think it may be salvageable? thanks, George Quote Link to comment Share on other sites More sharing options...
Bean Posted May 4, 2007 Report Share Posted May 4, 2007 170K on the pistons means that you definitely have blow by - but it's unavoidable with those miles. Do a compression test dry, then squirt some oil in and take it again. (1 tsp per cylinder). The increase after the oil will give you an idea of how much blow by you're getting. All 4 should be within 10%of each other. If that checks out - then yes - it should be possible to get it running in tip top shape. Rabin Quote Link to comment Share on other sites More sharing options...
geo Posted May 18, 2007 Author Report Share Posted May 18, 2007 170K on the pistons means that you definitely have blow by - but it's unavoidable with those miles. Do a compression test dry, then squirt some oil in and take it again. (1 tsp per cylinder). The increase after the oil will give you an idea of how much blow by you're getting. All 4 should be within 10%of each other. If that checks out - then yes - it should be possible to get it running in tip top shape. Rabin OK, I finally got the STX on the road and out of the garage so I was able to do a compression check on the SW8 N9TEA. Here are the results: #1 120 psi #2 92 psi #3 90 psi #4 122 psi So it looks like either a bad head gasket/cracked head again! between 2 and 3 and maybe some bad ring landings to boot. What is the normal compression on this engine? I'm thinking about 127 psi (7.5:1compression ratio * 17) Is that right? I couldn't find the spec in my engine manual. Also, what does everyone think I should do? I know I need to pull the head, but I'm assuming pull the pistons out also? thanks in advance, George Quote Link to comment Share on other sites More sharing options...
Toni Lindroos Posted May 22, 2007 Report Share Posted May 22, 2007 #1 120 psi #2 92 psi #3 90 psi #4 122 psi So it looks like either a bad head gasket/cracked head again! between 2 and 3 and maybe some bad ring landings to boot. What is the normal compression on this engine? I'm thinking about 127 psi (7.5:1compression ratio * 17) Is that right? I couldn't find the spec in my engine manual. Here's what I got from my European 1985 Turbo Injection #2 (N9TE, 8:1 compression ratio): Cyl. 1: 11,75 bar = ~170 psi Cyl. 2: 11,75 bar = ~170 psi Cyl. 3: 11,5 bar = ~ 167 psi Cyl. 4: 11,75 bar = ~170 psi Quote Link to comment Share on other sites More sharing options...
geo Posted October 14, 2007 Author Report Share Posted October 14, 2007 Here's what I got from my European 1985 Turbo Injection #2 (N9TE, 8:1 compression ratio): Cyl. 1: 11,75 bar = ~170 psi Cyl. 2: 11,75 bar = ~170 psi Cyl. 3: 11,5 bar = ~ 167 psi Cyl. 4: 11,75 bar = ~170 psi Update: I had two cracked pistons and one broken ring. So I rebuilt the engine. It's back in the car and running well, but I can't seem to get the vacuum hoses right. What I have in the car doesn't match my repro factory manual. Does anyone have a picture of vacuum hose routing for an N9TEA? Or anyway someone can describe how they are supposed to be connected? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
august Posted October 23, 2007 Report Share Posted October 23, 2007 Update: I had two cracked pistons and one broken ring. So I rebuilt the engine. It's back in the car and running well, but I can't seem to get the vacuum hoses right. What I have in the car doesn't match my repro factory manual. Does anyone have a picture of vacuum hose routing for an N9TEA? Or anyway someone can describe how they are supposed to be connected? Thanks in advance. i'm sure someone here can help with that. what vacuum hoses are you talking about? there are quite a few ... all of them? Quote Link to comment Share on other sites More sharing options...
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