If only boost is producing the smoke and prior vacuum has no influence on it then a leaking turbo seal is a likely suspect. It sounds like the oil flow is still slow enough that it wouldn't be leaving residue though. The oil just goes directly into the turbine housing and out the exhaust. The exhaust heat can keep the nearby surfaces burned clean for a long time. ----- Original Message ----- From: Larry Alster To: 'Bob Bundy' ; 'M. Ybarra' ; [email protected] Sent: Tuesday, July 29, 2008 3:26 AM Subject: RE: Tailpipe smoking under load.
Turbo seals?? I know you're seeing it mostly in cylinder #1 but is there a chance that the heaviest amount of oil is just getting into there by the flow pattern. You might need to remove the turbo or manifold and look and see how much oil is in it. Larry White Knight 1991 Crystal White #99 CSP Silver Bullet 1992 Silverstone #17 SM2 FM I+ Turbo Honey B 1992 Sunburst Yellow #99 SM2L JR Supercharger Whooosh 2004 Titanium Mazdaspeed MX-5 LowCountry Miata http://www.lowcountrymiataclub.net Masters Miata RAGS 074 From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bob Bundy Sent: Tuesday, July 29, 2008 1:02 AM To: M. Ybarra; [email protected] Subject: Re: Tailpipe smoking under load. I drove it 250 miles round trip to an autocross did 8 runs and returned home and it burned a little over 1 quart of Oil. I can drive around and go down hill with huge vacuum then accelerate without going into boost and don't see blue smoke in the rear view. Seems like high vacuum would suck in oil if it was valve guides. It also doesn't smoke noticeably when I first start it up or just let it idle. It smokes quite a bit of blue smoke when I go into boost whether boost was proceeded by vacuum or not. PCV removed and replaced with a hose to the catch can doesn't change anything. no blowby in the breather catch can ether. No oil leaks around the engine, oil is going out the tailpipe. Cylinder #1 shows a fair amount of oil contamination on the plug and the top of the piston and none of the others do. I don't measure bad compression or leakdown in any of the cylinders and it doesn't feel noticeably down on power, dynoed at 338 hp with good and slightly conservative afr. I replaced valve stem seals on the intake for cylinder #1 without removing head. valves seemed reasonably tight in the guides when I wiggled and spun the valves by hand. I saw no glaring issues. no change in tailpipe smoke though. Bob ----- Original Message ----- From: M. Ybarra To: [email protected] Sent: Saturday, July 26, 2008 8:58 PM Subject: Re: Tailpipe smoking under load. Normally, valve guides or valve guide seals show failure during idle (smoking like mad) not while the engine is under load or positive manifold pressure. Guide seals are supposed to control oil flow to prevent galling between the valve guide and valve stem, not stop it entirely. IMHO, it is likely the shop either damaged the valve guide during the install, reamed the guide too much or the stem was out of spec and there is too much play between it and the guide. This would cause the excessive oil flow and may be the source of problem you are having. Myron ----- Original Message ----- From: Bob Bundy To: [email protected] ; [EMAIL PROTECTED] Sent: Saturday, July 26, 2008 8:37 PM Subject: Re: Tailpipe smoking under load. I have had the same turbo drain on the car for a year and a half and never had a problem. With my turbo placement the drain is short about 6" long including fittings 5/8" ID and slopes into the pan with two 45 degree -10 AN pushlock fittings one at the turbo one at the pan, virtually impossible to kink because there is only about 1" of hose between the barbs on the fittings. I have a restrictor on the feed line as well and I also have no oil showing up in the intercooler piping. Just oil in and around one cylinder as near as I can tell. After changing the valve seals I don't think it is likely that it is seeping past the seal and between the guide and the stem. if it is a valve guide leaking it would be between the OD of the guide and the head I think, if that is possible. There is no drain back to the pan around the intake valve guides on the head by the #1 intake so the base of them sits in a pool of oil all the time more so than the others. Compression and leak down are good so if it's getting past rings it would be oil control rings only I think. cylinder walls and tops of the pistons looked good a few weeks ago as well. Seems like Oil is disappearing faster now I just put in another quart. Bob ----- Original Message ----- From: [EMAIL PROTECTED] To: [email protected] Sent: Saturday, July 26, 2008 3:33 PM Subject: Re: Tailpipe smoking under load. In a message dated 7/26/2008 2:04:25 P.M. Eastern Standard Time, [EMAIL PROTECTED] writes: Very little differance was made. I can drive it around in vacume and boost up to 5 maybe 10 psi and not see smoke. Full throttle 15psi and she smokes some. Bob Are you CERTAIN the oil is not coming from the turbo? If the drain on the turbo has a kink or simply does not drain quickly enough, the oil that doesn't drain will back up, go into the intake system, and eventually make its way out the tailpipe, and this is more likely to happen at higher boost levels. ------------------------------------------------------------------------ Get fantasy football with free live scoring. 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