Pop N Wood Posted May 23, 2007 Share Posted May 23, 2007 If I were you I would just quit looking at the exhaust. Quote Link to comment Share on other sites More sharing options...
Supra510 Posted May 24, 2007 Share Posted May 24, 2007 I had had a problem very similar to yours with my old turbo. I couldn't get it to smoke on deceleration, mostly it would occur once I was on boost, then decelerated. No smoke on deceleration (or on boost), but once on the gas again I would get a big puff of blue smoke. I made sure the oil drain was big enough, valve stem seals, breather tank. Nothing cured it. I had a little oil residue in the compressor inlet, but minimal shaft play. Nothing worked. Rebuilt the turbo which turned out to have quite a bit of shaft damage and all smoking issues went away. The only other smoking I ran into was at track days at the end of a long straight. Turns out my breather tank fittings were too small. I've since gone to a closed system with a catch tank that runs back to the intake. See write up here: http://www.cardomain.com/ride/674663/6 Quote Link to comment Share on other sites More sharing options...
GrayZee Posted May 24, 2007 Share Posted May 24, 2007 BTW maybe I should clarify. doing a HOT DRY test at 5,800 feet up.. with a P90 head and F54 block, with a 2mm headgasket and aftermarket cam... I had 100psi across the board and 110psi WET! I honestly can't speak for how the 5800ft and the head gasket/cam mods will effect it, but to me 100psi sounds low.. really low. Last time I checked I had like 150psi on a high mileage engine, and my buddies freshly rebuilt L28et had 160psi. Perhaps it is your rings? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 24, 2007 Author Share Posted May 24, 2007 the motor was 135psi cold and dry two months ago. the new cam and new headgasket and HOT dry tests months later dropped the compression down considerably. Supra510.. when you built the catch can.. what do you use as check valve?! Under boost the catch can would be pressurized.. should there be a one way check valve?! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 24, 2007 Share Posted May 24, 2007 Reading your post about adding oil and only getting 10 more psi, I don't think it's rings. Compression testers are notoriously inaccurate too, so you were really doing the right thing by looking at the variance rather than the actual number. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 25, 2007 Author Share Posted May 25, 2007 Whew** Thanks Jon for takin a closer look at it! With all honesty.. I believe its the turbo. BUT.. only way to tell is run without the turbo and see what happens! I just need to find a day to dink around with it.. and enough time to allow the motor to cool and reinstall the turbo Quote Link to comment Share on other sites More sharing options...
steveosupremeo Posted May 25, 2007 Share Posted May 25, 2007 how much oil did you put in each cylinder, that makes a difference too, but the fact that they all went up the same amount is good. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 25, 2007 Author Share Posted May 25, 2007 I added 2 small squirts.. so I want to say roughly 1tsb or so. at first I made a booboo.. and shot in WAYY too much oil.. and gear oil too.. so the compression went to 200psi.. LoL so I added a small squirt and the numbers went up pretty much the same across the board Quote Link to comment Share on other sites More sharing options...
EZ-E Posted May 25, 2007 Share Posted May 25, 2007 From reading all of this I have come to one conclusion, I would say its more then likely your turbo going. Though I could not be sure of this, this is what it sounds like, either bad seals and or worn bearing or shaft play. As far as your compression goes though I would have to agree with GrayZee, your compreesion readings do seem to be really low. I dont know how much the cam has changed that, or cam timing either. I know that with my ZXT I had, which was an 82 F54 block P90a head, I had a 1.2 mm HKS metal HG, and compression across the board was at 150. Yours just seems really low, but as jmortensen said I cant think that it is the rings, not with what you posted here. Final analyisis, turbo is your problem. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted May 25, 2007 Share Posted May 25, 2007 Ryan, did you take those compression readings with the new cam? I ask because I know that longer duration cams result in a lower "effective" compression ratio allowing you to run a higher CR without detonation. I suspect this may be part of what is going on with your readings. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 25, 2007 Author Share Posted May 25, 2007 Yes the readings are with the NEW cam.. 260 duration.. and with the 2mm hg. and keep in mind the engine was HOT and dry I drove the car till operating temp and took a compression test. Density altitude during the day was around 8000 feet.. so with heat soak in the cylinders and warm engine.. the density altitude in the cylinders was probably around 9000-10000 feet. I believe the lower compression numbers are do to the intake valve being open longer, which means the piston is moving up slightly with the intake valve open. Or so I understood from zcar.com Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted May 25, 2007 Administrators Share Posted May 25, 2007 Density altitude during the day was around 8000 feet.. so with heat soak in the cylinders and warm engine.. the density altitude in the cylinders was probably around 9000-10000 feet. Only pilots talk that way Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 26, 2007 Author Share Posted May 26, 2007 LoL.. ya a pilot Ron?! Im workn on my instrument rating right now .. commercial by the end of the summer =) Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted May 26, 2007 Administrators Share Posted May 26, 2007 LoL.. ya a pilot Ron?! Roger that. Im workn on my instrument rating right now .. commercial by the end of the summer =) Very good!... how far along in your IR training? I'm 'finished' with my IR so to speak... passed the written (most difficult test I've ever taken) and fulfilled all curriculum requirements. I just need to take the practical. I'm slowly plinking away at a CFI position. Probably get stretched out over years, as instructing would be primarily for the enjoyment of it. I expect a ping when you get your IR and Commercial. Best of luck! Quote Link to comment Share on other sites More sharing options...
Supra510 Posted May 26, 2007 Share Posted May 26, 2007 Supra510.. when you built the catch can.. what do you use as check valve?! Under boost the catch can would be pressurized.. should there be a one way check valve?! The catch can is routed back to the turbo intake. The catch can traps the oil vapor that comes in through the 2 smaller tubes from the cam covers. The the pressure then goes out the large tube to the intake that enters the compressor housing. A lot of Supra's run this set up. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 26, 2007 Author Share Posted May 26, 2007 Thanks Anthony... But with a catch can I still need a PCV valve or check valve inbetween correct?! If the large tube goes to the intake manifold or compressor housing.. when the turbo provides boost.. your now sending the pressure into the catch can, and pressure into the valve cover and block vent. So I can run a catch can, I just need a check valve correct?! Ron I am about 10 flights from my Check Ride.. i need to take my written soon. *shivers* Before next May I need my instrument, commercial, CFI, CFII, Multi engine, AGI and MEI. yep im broke. Quote Link to comment Share on other sites More sharing options...
Supra510 Posted May 26, 2007 Share Posted May 26, 2007 No check valve needed. You route the pressure back to the compressor inlet which is always under a vacuum condition whether under boost or not. I've attached a pic Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted May 27, 2007 Author Share Posted May 27, 2007 ohh I see.. hey that might fix my problem!! Let me build one up this week and try it out!! Thanks Anthony! Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 14, 2008 Author Share Posted February 14, 2008 I should probably post a FIX to this problem from my experience.. I simply added an inline PCV valve and this fixed the problem!! I added a vacuum tee from the brake booster line.. and added the inline PCV. block vent tube > hose > PCV valve > hose > vacuum tee to intake manifold! I ran the setup OPEN for one day to see what happened and the smoke poured out! I hooked the valve back up and NO smoke! I never need to refill my oil now! whoo! Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted February 14, 2008 Share Posted February 14, 2008 Is the valve cover still open? My PCV in my manifold is still hooked up and it was smoking... I disconnected it today (both venting to atmosphere) and it seems like the smoke went away. I think the PCV might be defective and pressurizing my crankcase... Mario Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.