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View Full Version : Oil smoke from hot-air motor (Was: Newbie questions.)


DWB47
07-17-2009, 10:05 AM
Hi everyone. I'm about to purchase my first turbo buick and I have a few questions. The car I'm looking at is an 85 regal NA with a non intercooled 3.8 turbo swapped into it. I like the car, the body is straight and rust free. I don't care the if's it not a real turbo car, true turbo cars won't fit into my budget right now. The car runs good and drives good, but it smokes. It is definately oil smoke, it does it some at idle, and get progesively worse under boost. Is there a common problem that would cause this? He says that it has a rebuilt turbo with less than a few hundred miles on it. So I don't think it would be a turbo seal. He also said that a mechanic did a pressure test on it ansd it came back good, but he dosen't know the numbers. Could it be valve seals or guides, or does it sound more like rings? Thanks in advance for your help.

kenmosher
07-17-2009, 10:14 AM
Might be a lot of things ...


Worn/Bad Valve Guides
Bad PCV valve
Bad exhaust seal on turbo
Bad compressor seal on turbo
Rings
Bad intake manifold seal (to the inside)


This one isn't something that can be easily diagnosed over the web. If the car has good vacuum at idle (assuming it idles well?) then the intake manifold seal can probably be ruled out.

It really does sound suspiciously like a turbo seal though ...

DWB47
07-17-2009, 11:50 AM
Thanks for your input. I forgot to mention the the gasket on the exhaust outlet on the turbo leaks, and it is smoking from there as well. Does this tell you anything? The car idles fine, and drives fine it just smokes. At the price ($2000) I think the nice body and excellent interior is worth close to that. Worse case scenario I could pull the turbo motor and drop in a SBC. I know thats probably sacrilege on this site, but it's not a factory turbo car, and all I really want is a fast G body that I can drive daily and build on a budget. Does this sound like a good deal to you guys?

kenmosher
07-17-2009, 11:58 AM
$2000? Heck yeah!

Drivetrain is worth that ... does it have the 8.5" Rear end in it (was it transplanted from the donor car where the motor/trans came from?)

The smoking sure sounds like it might be valve guides,but for $2K, I think I'd just drive it awhile and see if anything obviously shows itself. A stock used turbo ought to be <$350 so if it drives out nice for awhile, you might just swap turbos and see what happens...

DWB47
07-17-2009, 12:32 PM
It has a 7.5 rear, but like I said I'm not looking to build a race car, at least not right away. Whoever did the swap did a good job, they even changed the cluster. It smokes quite a bit so I don't think I'll be driving it until I fix the smoke issue. Also the guy told me that the turbo is freshly rebuilt, he said it was sent off to turbochargers.com for a rebuild. Is it possible they didn't build it right and it's leaking?

DWB47
07-20-2009, 09:34 PM
Well, I brought the car home tonight. So where do I begin to figure out this smoking issue. It smokes some on start up, and gets worse with throttle. I'm going to do a compression check, and pull off the downpipe to check for oil. Also it appears that oil is dripping from the backside of the turbo. What else should I check?

DWB47
07-22-2009, 08:23 PM
I took the exhaust elbow off the turbo, and it was full of oil, and there is alot of play in the shaft. Also the turbo drain pipe is kinked and cracked. There is oil all over the trans and back of the motor. So I guess since the turbo couldn't properly drain it just blew out the seal. Any suggestions on a good turbo rebuilder. Where can I find a drain tube, I have found quite a few for intercooled motors but none for a hot air motor? Thanks.

Keller
07-23-2009, 01:40 AM
I would suggest Limit Engineering for the rebuild. http://www.limitengineering.com/

DWB47
07-23-2009, 09:46 AM
Thank you.