Slight oil smoke (?) at idle... working the bugs out..
04-22-2013, 07:50 PM
#1
Slight oil smoke (?) at idle... working the bugs out.. I have twin Precision 6262 CEA journel bearing turbos. I have two unrestricted -4AN feed lines and two -10AN drains to the oil pan. These are BRAND NEW turbos. Slight oil smoke out of both down pipes after a few mins of idling. I have pretty high oil PSI at idle (about 60 psi-ish and right to like 80 on a cold start). My car is also running pretty rich right now on a base tune (like 11:0 ehhh) but i don't think this is fuel smoke..
That being said, i know Precision says not to run a restrictor, but i have seen where some people have called Precision and they said to run a restrictor when the oil PSI is above a certain point etc. After a quick search i have seen some people running a -3AN line with these turbos, running a restrictor, running no restrictor..so a real mixed bag. I ran an unrestricted -4 and -10 drain on my Precision 76GTS with no problem but these turbos are quite a bit smaller....
what say you LS1tech?? I hate the bugs to work out on new build... FML.
That being said, i know Precision says not to run a restrictor, but i have seen where some people have called Precision and they said to run a restrictor when the oil PSI is above a certain point etc. After a quick search i have seen some people running a -3AN line with these turbos, running a restrictor, running no restrictor..so a real mixed bag. I ran an unrestricted -4 and -10 drain on my Precision 76GTS with no problem but these turbos are quite a bit smaller....
what say you LS1tech?? I hate the bugs to work out on new build... FML.
Last edited by jt76; 04-22-2013 at 08:33 PM.
04-22-2013, 09:17 PM
#5
Go drive it and see. I bet it clears up after a bit. All the oil inside the new piping and everything else takes some time. I had a scavenge pump go bad and fill the exhaust system front to rear with oil. It took about 30 miles worth of driving to get it all burned out.
04-22-2013, 09:46 PM
#6
Go drive it and see. I bet it clears up after a bit. All the oil inside the new piping and everything else takes some time. I had a scavenge pump go bad and fill the exhaust system front to rear with oil. It took about 30 miles worth of driving to get it all burned out.
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04-23-2013, 11:04 AM
#9
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I never use a restrictor on a precision. but sounds like you might have too.Double check your drain which Im sure you have and get that thing leaned out to make sure its not fuel. Trust me I've been there before.
04-23-2013, 12:00 PM
#10
Drains are good, great angle and a decent size. I just got off the phone with precision and they said that crankcase ventilation might be the problem. I have a vent off each valve cover that worked fine when i had the single 76 but the rep thought that it could be that with the 76 I had more backpressure than with the twins so now the crankcase vent could be an issue... He said restrictors are a last resort (which seems to be the company line over there)
04-23-2013, 12:10 PM
#11
Get the fueling right. Since your gas it could easily be that. I'm running twins with twin -4 feeds and twin -10 drains. It smoked slightly like you are describing for the initial start up (I was new motor) but was gone 30 minutes later and it never smokes now. Not even after a dyno pull.
04-23-2013, 12:22 PM
#12
Yeah, maybe i'll have my friend come over later and take some fuel out. Just went out and had both valve cover breathers open, the oil cap off and the dipstick pulled up, so plenty of crankcase vent, and after about 5 mins of idling it started to smoke..... my gut is i think they are getting too much oil... why would it be absolutely fine for the first 5 mins or so and then start to smoke?
04-23-2013, 12:50 PM
#13
Yeah that doesn't seem right. I can tell you it can't hardly be the oil pressure. I have the high volume/high pressure Mellings pump and I am running no less than 50 psi hot idle.
04-23-2013, 01:13 PM
#14
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If it is light smoke and it starts a few minutes AFTER start-up....oil is backing up in your drain lines...
If your drain lines are above the oil level in the pan and are routed properly with no low spots, I would look at a better pcv set-up. A small amount of negative pressure at idle in the crankcase can keep the oil from backing up the lines.
If your drain lines are above the oil level in the pan and are routed properly with no low spots, I would look at a better pcv set-up. A small amount of negative pressure at idle in the crankcase can keep the oil from backing up the lines.
04-23-2013, 01:19 PM
#15
If it is light smoke and it starts a few minutes AFTER start-up....oil is backing up in your drain lines...
If your drain lines are above the oil level in the pan and are routed properly with no low spots, I would look at a better pcv set-up. A small amount of negative pressure at idle in the crankcase can keep the oil from backing up the lines.
If your drain lines are above the oil level in the pan and are routed properly with no low spots, I would look at a better pcv set-up. A small amount of negative pressure at idle in the crankcase can keep the oil from backing up the lines.
04-23-2013, 01:59 PM
#16
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That could help. But I've never did a Pcv system in any of my ls turbo cars I have 2 right now that are just venting into the atmosphere . But it's not a problem to hook up a pcv system you might give it a try.
04-23-2013, 02:13 PM
#17
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First few timie running mine i got some oil pushing out the downpipe as well.. I have s475 borg warner.. I vented crank case better and it just stopped on its own.. so i dont know if its what i did or the turbo just had to heat and cool a few times to seal right. It wasnt comin from engine cause i pulled o2s out to see if they where oily.. But its good now lol
Last edited by mrstepheneades; 04-23-2013 at 02:44 PM.
04-23-2013, 03:06 PM
#18
Yeah, i had my old single setup just vented as do two of my friends on theirs, but no one around here is running twins.... And as i said, i opened the oil fill cap and oil dipstick tube in addition to the other vents and it still started doing it. I seriously wonder if they are getting too much oil... i see people running -3 feeds on these, possibly run a restrictor equal to the I.D of a -3 line?
04-23-2013, 03:35 PM
#19
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Yeah, i had my old single setup just vented as do two of my friends on theirs, but no one around here is running twins.... And as i said, i opened the oil fill cap and oil dipstick tube in addition to the other vents and it still started doing it. I seriously wonder if they are getting too much oil... i see people running -3 feeds on these, possibly run a restrictor equal to the I.D of a -3 line?
Yeah I have -3 on both of mine. My corvette is twin turbo but they're ball bearing turbo's so I run a restrictor on those.. But my fairmont has a journal type like yours and no restrictor.
04-23-2013, 04:30 PM
#20
LMAO, this whole crank case vent thing is a new line for turbo companies I guess. In the import market I had a friend get the same line when his turbo started smoking and pushing oil out of both the exhaust and the intake side (which they said should not happen, but it was!). I really think there is just a quality control issue with some companies and they get these lines given to them to try to shrud it off in hopes that the customer will just go away or think it was something they did.
Also had a customer with a brand new Precision journal bearing that smoked from day one. Tried a different turbo in its spot, no issues. Sent it off to Precision for a rebuild, get it back, same thing. Despite all this he decided to get a BB Precision and that one with a restrictor had zero issues. Not sure what it is with their journal bearing stuff, but this seems to be a regular theme.
Also had a customer with a brand new Precision journal bearing that smoked from day one. Tried a different turbo in its spot, no issues. Sent it off to Precision for a rebuild, get it back, same thing. Despite all this he decided to get a BB Precision and that one with a restrictor had zero issues. Not sure what it is with their journal bearing stuff, but this seems to be a regular theme.