Turbos smoking at idle. Please help!
07-16-2016, 11:12 AM
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Turbos smoking at idle. Please help! Hey guys, seeking some turbo help here. I've had twin Precision 6265 billet journal bearing turbos on my GTO for several years now (only 3-4k miles though) and never had any issues with them until I dropped in a freshly rebuilt 5.3 engine with a new Melling high volume oil pump. Smoke was coming out the exhaust after starting up the 5.3 since the first startup, once I let things heat up at idle. After loosening up the V-bands on the exhaust side of the turbos and witnessing oil burning from the turbos, I decided to try some oil restrictors where my -4 lines enter the turbos. The restrictors without the jets installed within them didn't seem to help, and the largest jet didn't help either, but the smallest jet for the restrictor did the job. No more smoke burning out of the exhaust.
A couple months later I took the car to the track for the first time in a few years and after the 3rd pass I was blowing oil out my exhaust like you wouldn't believe. Found a bit of play on the turbine shaft on my passenger's side turbo. I had a reputable shop in Virginia rebuild that passenger's side turbo, and decided to leave the driver's side turbo alone unless I later found it to need rebuilding too. Assuming the cause of the passenger's turbo failing on me was likely due to a lack of oil, I removed the restrictors from oil supply lines, hoping that at least the rebuilt turbo wouldn't smoke without an oil restrictor (expecting maybe it was already needing rebuilt at the time of dropping in the 5.3). Well, now I'm right back to the same problem-- the turbos smoke. Putting the restrictors with the smallest jets back in place on the turbos yesterday didn't clean up the smoke on either turbo. I did notice that the turbos are only smoking at idle. If I bring up the RPM the turbos stop smoking, and only start smoking again a few seconds after I let the engine return to idle.
Now I'm wondering if the problem is too much pressure in the crank case, though this was never previously an issue. I have both 3/8" nipples in the valve covers venting to the atmosphere, and also have a breather oil filler cap on the driver's valve cover. According to my boost/vac gauge the engine is at about 10-11 Hg at idle... not sure if that's a sign of anything.
So as a refresher, the turbos are only smoking after the engine warms up, and they only seem to smoke at idle. Any ideas on what could be the cause based on the info above???
Below is a video I took with the engine at idle and the V-bands on the exhaust side of the turbos disconnected. I disconnected the V-bands to get a more immediate look at what's happening, so be prepared that the car sounds awful like this. But this eliminates the possibility of residual oil in the exhaust (from when the driver's turbo had issues at the track) being what's burning, and which turbo(s) is causing the issue since I also have an X-pipe the exhaust.
I also just recalled that I used to run check valves on the 3/8" hose that leaves each valve cover, that vented to the atmosphere. I had things setup that way until I dropped the 5.3 in, which is when I removed the check valves and just put filters on the ends of the hoses due to someone else's suggestion. Though the crankcase can now suck in air and pressurize without the check valves in place, I would think the lines would still vent when needed now with no check valve in place... but am I missing something here? Is there any reason to just go and put the check valves back on the lines? Do I perhaps have a vacuum hose somewhere else that isn't routed the proper fitting or something that would cause this??? Thanks a bunch!!!!
P.S. Some other "homework" and info:
-Precision Turbo claims these turbos are good for up to 120 PSI. Even with the new Melling oil pump I'm making around 90 PSI on the factory oil pressure sensor on the engine. Not sure how much each turbo is getting, but I'm sure it's under 90, especially since the oil feed coming out of the engine is split into 2 before hitting the turbos.
-My drain lines are -10, and there are no kinks nor dips in the lines. The turbos are clocked nearly straight up and down. None of this has changed since before the turbos started smoking.
-The PCV system venting to the atmosphere is how everything has always been setup since I first had the turbo system fabricated and there was no smoking issue. I do get some spray out of the oil filler breather, I assume at heavy and/or full throttle. I notice oil sprayed on the passenger's side of the strut tower brace after I have driven the car hard.
-I recently mounted an oil catch can in the engine bay, but haven't hooked it up yet, so I'm not sure if oil is building up from the crankcase or not at this time.
A couple months later I took the car to the track for the first time in a few years and after the 3rd pass I was blowing oil out my exhaust like you wouldn't believe. Found a bit of play on the turbine shaft on my passenger's side turbo. I had a reputable shop in Virginia rebuild that passenger's side turbo, and decided to leave the driver's side turbo alone unless I later found it to need rebuilding too. Assuming the cause of the passenger's turbo failing on me was likely due to a lack of oil, I removed the restrictors from oil supply lines, hoping that at least the rebuilt turbo wouldn't smoke without an oil restrictor (expecting maybe it was already needing rebuilt at the time of dropping in the 5.3). Well, now I'm right back to the same problem-- the turbos smoke. Putting the restrictors with the smallest jets back in place on the turbos yesterday didn't clean up the smoke on either turbo. I did notice that the turbos are only smoking at idle. If I bring up the RPM the turbos stop smoking, and only start smoking again a few seconds after I let the engine return to idle.
Now I'm wondering if the problem is too much pressure in the crank case, though this was never previously an issue. I have both 3/8" nipples in the valve covers venting to the atmosphere, and also have a breather oil filler cap on the driver's valve cover. According to my boost/vac gauge the engine is at about 10-11 Hg at idle... not sure if that's a sign of anything.
So as a refresher, the turbos are only smoking after the engine warms up, and they only seem to smoke at idle. Any ideas on what could be the cause based on the info above???
Below is a video I took with the engine at idle and the V-bands on the exhaust side of the turbos disconnected. I disconnected the V-bands to get a more immediate look at what's happening, so be prepared that the car sounds awful like this. But this eliminates the possibility of residual oil in the exhaust (from when the driver's turbo had issues at the track) being what's burning, and which turbo(s) is causing the issue since I also have an X-pipe the exhaust.
I also just recalled that I used to run check valves on the 3/8" hose that leaves each valve cover, that vented to the atmosphere. I had things setup that way until I dropped the 5.3 in, which is when I removed the check valves and just put filters on the ends of the hoses due to someone else's suggestion. Though the crankcase can now suck in air and pressurize without the check valves in place, I would think the lines would still vent when needed now with no check valve in place... but am I missing something here? Is there any reason to just go and put the check valves back on the lines? Do I perhaps have a vacuum hose somewhere else that isn't routed the proper fitting or something that would cause this??? Thanks a bunch!!!!
P.S. Some other "homework" and info:
-Precision Turbo claims these turbos are good for up to 120 PSI. Even with the new Melling oil pump I'm making around 90 PSI on the factory oil pressure sensor on the engine. Not sure how much each turbo is getting, but I'm sure it's under 90, especially since the oil feed coming out of the engine is split into 2 before hitting the turbos.
-My drain lines are -10, and there are no kinks nor dips in the lines. The turbos are clocked nearly straight up and down. None of this has changed since before the turbos started smoking.
-The PCV system venting to the atmosphere is how everything has always been setup since I first had the turbo system fabricated and there was no smoking issue. I do get some spray out of the oil filler breather, I assume at heavy and/or full throttle. I notice oil sprayed on the passenger's side of the strut tower brace after I have driven the car hard.
-I recently mounted an oil catch can in the engine bay, but haven't hooked it up yet, so I'm not sure if oil is building up from the crankcase or not at this time.
07-16-2016, 12:49 PM
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You can check the spark plugs to be sure that its not blow by or the pcv system dumping oil into the engine. But this is very doubtful, it would be a ton of oil getting past through the combustion to reach the turbos. You would be fouling plugs IMO.
You put restrictors in the feed lines which helped at one point, so that lets you know its the oil supply. And with the new engine, I am sure you are making more oil pressure now. And really, it was most likely the turbo seal getting a little weak already but you didn't have enough pressure to make it leak. Now the new, higher psi is showing the problem that had already started. Even though they are spec's to 120psi, that doesn't mean a lot really. That's when brand new. They do wear out eventually.
You put restrictors in the feed lines which helped at one point, so that lets you know its the oil supply. And with the new engine, I am sure you are making more oil pressure now. And really, it was most likely the turbo seal getting a little weak already but you didn't have enough pressure to make it leak. Now the new, higher psi is showing the problem that had already started. Even though they are spec's to 120psi, that doesn't mean a lot really. That's when brand new. They do wear out eventually.
07-17-2016, 08:19 PM
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Thanks for your input so far, everyone!
I'll go ahead and pull the plugs and look at them anyway just to be safe... this car hasn't really been driven anywhere due to the smoking issue, so I wouldn't really know if I was fouling them unless it's certain I'd see issues just bring the throttle up while parked.
So the restrictors were installed after the new engine. Nothing has really changed since I introduced the restrictors to the oil feeds, messed up one of the turbos, and reinstalled the rebuilt turbo. That's why I was kind of hoping that I'd find that only one of the turbos was causing the smoke, being the one that wasn't just rebuilt, but both the rebuilt one and the non-rebuilt one are smoking. The non-rebuilt one just a little more, but keep in mind it has no more than 4k miles on it. Doesn't mean a thing if debris got in the oil or something, I know, but shouldn't otherwise necessarily be needing rebuilt just yet unless it too is slightly damaged. It has normal play on the turbine shaft... the same amount of very minimal play as the one that was just rebuilt.
Yeah I'm starting to wonder if maybe I just over-filled my oil a little too much. My returns go into the very top of the front of the oil pan. I'm thinking about jacking the front of the car up some, so the oil rolls away from the front of the pan some, and see if it still smokes. Otherwise, nothing has changed about the drain lines since I first had these things spinning and the car wasn't smoking.
One of the turbos was literally just rebuilt and has less than 50 miles on it. Both turbos are smoking about the same... the one that was just rebuilt maybe a smidge less.
I do have the big catch can that I mounted but haven't connected to the PCV system just yet. My fear is that based on how much smoke is coming out the exhaust I'd just fill up the catch can after an hour of idling and would be having to dump it all the time, which means there's still a problem. Am I perhaps ignorant to this topic though and missing something? I'm honestly just trying to understand how/why a catch can could solve the issue if, say, too much oil pressure to the turbos is not the problem. That would collect fluid that would otherwise make its way into the intake manifold and such, but how would that contribute to the turbos smoking? Would it just re-enter the combustion chamber through the intake valves??
You can check the spark plugs to be sure that its not blow by or the pcv system dumping oil into the engine. But this is very doubtful, it would be a ton of oil getting past through the combustion to reach the turbos. You would be fouling plugs IMO.
You put restrictors in the feed lines which helped at one point, so that lets you know its the oil supply. And with the new engine, I am sure you are making more oil pressure now. And really, it was most likely the turbo seal getting a little weak already but you didn't have enough pressure to make it leak. Now the new, higher psi is showing the problem that had already started. Even though they are spec's to 120psi, that doesn't mean a lot really. That's when brand new. They do wear out eventually.
You put restrictors in the feed lines which helped at one point, so that lets you know its the oil supply. And with the new engine, I am sure you are making more oil pressure now. And really, it was most likely the turbo seal getting a little weak already but you didn't have enough pressure to make it leak. Now the new, higher psi is showing the problem that had already started. Even though they are spec's to 120psi, that doesn't mean a lot really. That's when brand new. They do wear out eventually.
So the restrictors were installed after the new engine. Nothing has really changed since I introduced the restrictors to the oil feeds, messed up one of the turbos, and reinstalled the rebuilt turbo. That's why I was kind of hoping that I'd find that only one of the turbos was causing the smoke, being the one that wasn't just rebuilt, but both the rebuilt one and the non-rebuilt one are smoking. The non-rebuilt one just a little more, but keep in mind it has no more than 4k miles on it. Doesn't mean a thing if debris got in the oil or something, I know, but shouldn't otherwise necessarily be needing rebuilt just yet unless it too is slightly damaged. It has normal play on the turbine shaft... the same amount of very minimal play as the one that was just rebuilt.
One of the turbos was literally just rebuilt and has less than 50 miles on it. Both turbos are smoking about the same... the one that was just rebuilt maybe a smidge less.
I do have the big catch can that I mounted but haven't connected to the PCV system just yet. My fear is that based on how much smoke is coming out the exhaust I'd just fill up the catch can after an hour of idling and would be having to dump it all the time, which means there's still a problem. Am I perhaps ignorant to this topic though and missing something? I'm honestly just trying to understand how/why a catch can could solve the issue if, say, too much oil pressure to the turbos is not the problem. That would collect fluid that would otherwise make its way into the intake manifold and such, but how would that contribute to the turbos smoking? Would it just re-enter the combustion chamber through the intake valves??
07-17-2016, 08:25 PM
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I sure didn't. I'll be sure to check if I remove the drain lines from the fittings. I'm not sure what brand the shop used when they welded the fittings into the pan, but possibly Vibrant. Everything I used to get from the turbo to the fittings in the pan (hoes and more fittings) is Russell Performance.
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07-18-2016, 06:23 PM
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What did the turbo shop say about the failure when they repaired it ?
What was the damage ? lack of oil, too much oil, other ?
You talk about restrictors....exactly what size are you using ? A JB turbo should be able to cope with a fair bit of oil flow, especially with a good gravity drain.
And your drains are good ? above level of oil in the oil pan ?
It does seem an odd coincidence with the new motor the problem occurred...is there anything else that might have changed or happened during the swap ?
What was the damage ? lack of oil, too much oil, other ?
You talk about restrictors....exactly what size are you using ? A JB turbo should be able to cope with a fair bit of oil flow, especially with a good gravity drain.
And your drains are good ? above level of oil in the oil pan ?
It does seem an odd coincidence with the new motor the problem occurred...is there anything else that might have changed or happened during the swap ?
07-18-2016, 09:16 PM
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Thanks for your feedback Stevie. The shop didn't say specifically, but the turbine shaft was pretty burnt up with hot spots so I assume lack of oil.
Here are the restrictors I ran:
http://vibrantperformance.com/catalo...759175ba7f41c4
.030" was the only jet that stopped the smoking. After the new motor was installed, before I burnt up the one turbo, it was smoking at idle as well as under throttle, but I found that one of the return lines had a sag in it. I fixed the sag and the smoking stopped, but I left the restrictors in the turbos thinking it hadn't hurt anything so far after several dyno pulls with them installed, so it shouldn't hurt to leave them in. Who knows what results I may have seen after fixing the sag in the one return line if I had removed the restrictors.
The drains should be good now. I looked at them several times, and everything flows down-hill right into the oil pan. Unless the oil level is beyond (higher than) the bottom of the return fittings in the oil pan, I don't anticipate there is a problem with the oil flowing back into the pan. But then returns the thought of too much crankcase pressure at idle, which I'm not sure is even a possibility with the valve covers vented the way they are.
Aside from ditching the perfectly fine, 20k mile LS2 oil pump for the Melling high volume oil pump, and aside from ditching the check valves in the valvecover breather hoses, I don't recall having changed anything else honestly. Maybe I routed a hose related to the PCV or vacuum system differently than before when I dropped the new motor in? Is there something I could have done with the routing of hoses to cause that??
Thanks again!!!
Here are the restrictors I ran:
http://vibrantperformance.com/catalo...759175ba7f41c4
.030" was the only jet that stopped the smoking. After the new motor was installed, before I burnt up the one turbo, it was smoking at idle as well as under throttle, but I found that one of the return lines had a sag in it. I fixed the sag and the smoking stopped, but I left the restrictors in the turbos thinking it hadn't hurt anything so far after several dyno pulls with them installed, so it shouldn't hurt to leave them in. Who knows what results I may have seen after fixing the sag in the one return line if I had removed the restrictors.
The drains should be good now. I looked at them several times, and everything flows down-hill right into the oil pan. Unless the oil level is beyond (higher than) the bottom of the return fittings in the oil pan, I don't anticipate there is a problem with the oil flowing back into the pan. But then returns the thought of too much crankcase pressure at idle, which I'm not sure is even a possibility with the valve covers vented the way they are.
Aside from ditching the perfectly fine, 20k mile LS2 oil pump for the Melling high volume oil pump, and aside from ditching the check valves in the valvecover breather hoses, I don't recall having changed anything else honestly. Maybe I routed a hose related to the PCV or vacuum system differently than before when I dropped the new motor in? Is there something I could have done with the routing of hoses to cause that??
Thanks again!!!
07-19-2016, 01:32 PM
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I would say 30thou is far too small for any JB turbo, that's smaller than most BB turbos run
If the crankcase is breathing clearly to atmos, then that should be more than adequate. Yea some people blab on about PCV and all that, but it's hard to beat the simplicity of breathing openly ( whether also via suitable filters or cans etc to prevent any oil getting spewed everywhere of course )
But most turbo/oil problems are either bad crankcase breathing, or bad oil return. So ensure they are both good, and then you can start looking into oil supply or the actual turbos themselves.
If the crankcase is breathing clearly to atmos, then that should be more than adequate. Yea some people blab on about PCV and all that, but it's hard to beat the simplicity of breathing openly ( whether also via suitable filters or cans etc to prevent any oil getting spewed everywhere of course )
But most turbo/oil problems are either bad crankcase breathing, or bad oil return. So ensure they are both good, and then you can start looking into oil supply or the actual turbos themselves.
07-20-2016, 07:59 AM
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I would say 30thou is far too small for any JB turbo, that's smaller than most BB turbos run
If the crankcase is breathing clearly to atmos, then that should be more than adequate. Yea some people blab on about PCV and all that, but it's hard to beat the simplicity of breathing openly ( whether also via suitable filters or cans etc to prevent any oil getting spewed everywhere of course )
But most turbo/oil problems are either bad crankcase breathing, or bad oil return. So ensure they are both good, and then you can start looking into oil supply or the actual turbos themselves.
If the crankcase is breathing clearly to atmos, then that should be more than adequate. Yea some people blab on about PCV and all that, but it's hard to beat the simplicity of breathing openly ( whether also via suitable filters or cans etc to prevent any oil getting spewed everywhere of course )
But most turbo/oil problems are either bad crankcase breathing, or bad oil return. So ensure they are both good, and then you can start looking into oil supply or the actual turbos themselves.
My other concern is that I might need bigger fittings welded to the valve covers so I can install some bigger hose for things to vent. A friend told me last night that there is a restrictor on the factory 3/8" 90-degree factory nipples coming out of the valve covers, so I may start with trying to remove those first if that's true. I just hope I don't have to upgrade to -12 returns because that's going to mean yanking the engine back out to remove the oil pan, buy a new oil pan to weld the fittings into, and then re-install everything with new lines. Total PITA with all this turbo piping in the engine bay that is VERY tightly fit and very tricky to fit together
Is that it is though, if it comes down to that lol.Haha! I think I'll have a hard time convincing people that it's performing extremely well at idle.