I'm working on my turbo N*. I wrapped the turbine housing and the pipes with insulation. The first time I ran it after I wrapped it, it started blowing oil smoke, lots of it. I just started the car and let it idle to warm up, and by the time the coolant temp hit 160 it was smoking bad. I ran it up to operatng temp and then shut it off and let it cool down. I have a -4AN oil feed line, no restrictor or any type of pressure reduction. -8AN return line going into the timing cover on the front of the engine. The turbo is about 10 inches above the return on the engine, but the return line is about 4 ft long and is horizontal for much of it's length. This worked fine until I wrapped the pipes. I just added a .060" restrictor in the oil feed fitting on the turbo. Warmed it up again, still smokes, maybe not quite as bad, but still unacceptable. I guess the next step is to measure the actual oil pressure at the turbo, and try to improve the return line.
I'm looking for any comments as to why this happened and what I can do to correct it. It's obvious that the insulation is keeping more heat in the turbo, but why does that make the seals fail? I'm fairly sure if I unwrap the pipes and turbine housing, the smoking will stop, but why?
Turbos: oil seals vs. heat
Moderators: The Dark Side of Will, Series8217
Re: Turbos: oil seals vs. heat
I would make sure that is the case first.
More heat = more expansion, but I don't think that's what's causing it to smoke.rockcrawl wrote: I'm fairly sure if I unwrap the pipes and turbine housing, the smoking will stop, but why?
Re: Turbos: oil seals vs. heat
I'm not familiar with N*s, but why are you not running the oil return line to the oil pan?
If you want to rule out the feed line, you're going to need an oil pressure gauge and find out what your turbo manufacturer recommends as far as oil pressure goes.
If you want to rule out the feed line, you're going to need an oil pressure gauge and find out what your turbo manufacturer recommends as far as oil pressure goes.
rockcrawl wrote:I have a -4AN oil feed line, no restrictor or any type of pressure reduction. -8AN return line going into the timing cover on the front of the engine. The turbo is about 10 inches above the return on the engine, but the return line is about 4 ft long and is horizontal for much of it's length. This worked fine until I wrapped the pipes. I just added a .060" restrictor in the oil feed fitting on the turbo. Warmed it up again, still smokes, maybe not quite as bad, but still unacceptable. I guess the next step is to measure the actual oil pressure at the turbo, and try to improve the return line.
-
Shaun41178(2)
- Posts: 8483
- Joined: Fri Nov 19, 2004 7:12 pm
- Location: Ben Phelps is an alleged scammer
I agree with howard. I would unwrap the pipes first and see if that stops the smoking. I highly doubt it will. I think it might have been a matter of coincidence of you wrapping the turbo and the oil starting to happen. Hondas, supras and many other cars wrap their turbos and exh and they dont' have smoking issues.
You do need to hook up a oil pressure guage however. If you had no restrictor in your feed line before you wrapped it that will cause way too much oil pressure. The n star pumps a lot of oil and does it at higher then recommended pressures for turbos. It could have been beating the seals up the whole time and you not know it untill one day they just go bad.
I also wonder why the return isnt' going to the pan but maybe you did that because of routing issues. I guess as long as the timing cover feeds back into the pan then I guess you should be ok. I would maybe step up your return line to a -10an, however I do think a -8 is fairly large enough. I do think you need to find a way to get the return line however to be more gravity freindly. Being a horizontal return for most of the way like you state does not help with the oil leaving the turbo. You want it to use gravity
I am guessing the high oil pressure was always putting a strain on your turbo seals as well as the improper drainage and perhaps oil backing up. So the seals are getting too much pressure and are being weakened this whole time. Now you wrap the pipes and go to start it, and that sudden burst of oil pressure on the seals at startup(remember oil pressure is always higher at startup because its cold) was enough to finally do them in and allow oil past and into the exh. This most likely would have happened even if you didnt' wrap the exh that day and it was just coincidence that it did.
I am guessing the seals are shot so you are prob going to have to put new ones in it. What size turbo are you running anyways? Hell maybe even upgrade it.
You do need to hook up a oil pressure guage however. If you had no restrictor in your feed line before you wrapped it that will cause way too much oil pressure. The n star pumps a lot of oil and does it at higher then recommended pressures for turbos. It could have been beating the seals up the whole time and you not know it untill one day they just go bad.
I also wonder why the return isnt' going to the pan but maybe you did that because of routing issues. I guess as long as the timing cover feeds back into the pan then I guess you should be ok. I would maybe step up your return line to a -10an, however I do think a -8 is fairly large enough. I do think you need to find a way to get the return line however to be more gravity freindly. Being a horizontal return for most of the way like you state does not help with the oil leaving the turbo. You want it to use gravity
I am guessing the high oil pressure was always putting a strain on your turbo seals as well as the improper drainage and perhaps oil backing up. So the seals are getting too much pressure and are being weakened this whole time. Now you wrap the pipes and go to start it, and that sudden burst of oil pressure on the seals at startup(remember oil pressure is always higher at startup because its cold) was enough to finally do them in and allow oil past and into the exh. This most likely would have happened even if you didnt' wrap the exh that day and it was just coincidence that it did.
I am guessing the seals are shot so you are prob going to have to put new ones in it. What size turbo are you running anyways? Hell maybe even upgrade it.
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL
BEWARE OF BEN PHELPS. YOU HAVE VEEN WARNED. WORSE THAN MILZY IMO
530 whp is greater than 312
BEWARE OF BEN PHELPS. YOU HAVE VEEN WARNED. WORSE THAN MILZY IMO
530 whp is greater than 312
-
The Dark Side of Will
- Peer Mediator
- Posts: 15632
- Joined: Wed Nov 24, 2004 11:13 pm
- Location: In the darkness, where fear and knowing are one
- Contact:
Re: Turbos: oil seals vs. heat
Because the front cover is sheet metal and the pan is cast aluminum...eHoward wrote:I'm not familiar with N*s, but why are you not running the oil return line to the oil pan?
How long did you run it before the wrap? If it was driven before the wrap was put on and it didn't smoke, that's very strange. What is the condition of the turbo? Is the length of drain hose routing the oil forward (like if you were accelerating, will the oil fight againt the pull of the car... not that it matters since you were ideling).
If the turbo is fresh, then this is strange.
If the turbo is fresh, then this is strange.
It's a new turbo, I've put about 200 smoke-free miles on it. I pulled it in the shop to install wideband and EGO sensors. Ran it in the shop for a total of about one hour while tinkering with the EFI, no smoke. Next day the DEI tubo insul kit arrived so I installed it. The car has not moved. I started the car and by the time it warmed up it was smoking bad.
I've done some research and thinking. I realized there was one other change I made when I wrapped the turbo (duh). I removed the catalytic converter. I learned something about the seals in a turbo. They are pressure differential type seals, more like a piston ring than a crankshaft oil seal. When I removed the cat I lowered the exhaust pressure on the turbine outlet and decreased the pressure differential on the seal. So I have not created a new problem, just unmasked an existing one. My oil feed/return system is not what it should be. The return line was questionable from the start, but since it worked I assumed it was OK. It's not.
The turbo is too low to improve drainage without a pump. Anyone have a suggestion for an electric scavenge pump? I cannot find much info on them except the Westech pump. Can I use an electric fuel pump like the Holley Red pump? Diesel transfer pump?
I've done some research and thinking. I realized there was one other change I made when I wrapped the turbo (duh). I removed the catalytic converter. I learned something about the seals in a turbo. They are pressure differential type seals, more like a piston ring than a crankshaft oil seal. When I removed the cat I lowered the exhaust pressure on the turbine outlet and decreased the pressure differential on the seal. So I have not created a new problem, just unmasked an existing one. My oil feed/return system is not what it should be. The return line was questionable from the start, but since it worked I assumed it was OK. It's not.
The turbo is too low to improve drainage without a pump. Anyone have a suggestion for an electric scavenge pump? I cannot find much info on them except the Westech pump. Can I use an electric fuel pump like the Holley Red pump? Diesel transfer pump?
-
The Dark Side of Will
- Peer Mediator
- Posts: 15632
- Joined: Wed Nov 24, 2004 11:13 pm
- Location: In the darkness, where fear and knowing are one
- Contact:
rockcrawl wrote:I've done some research and thinking. I realized there was one other change I made when I wrapped the turbo (duh). I removed the catalytic converter. I learned something about the seals in a turbo. They are pressure differential type seals, more like a piston ring than a crankshaft oil seal. When I removed the cat I lowered the exhaust pressure on the turbine outlet and decreased the pressure differential on the seal.
Now how did you lower turbine outlet pressure, yet reduce the pressure difference across the seal?
How much pressure are you seeing at the turbo?
Where are you sourcing the oil?
If the oil pressure was 5 psi and the turbine pressure was 10 psi, reducing turbine pressure would lower the difference. In reality, maybe the turbine pressure is lower than the oil pressure, the pressure difference would have increased, but with the same effect on the seal. I have no idea what the actual pressures are.
In any case, the oil pressure on the bearing side of the seal stayed the same and the pressure on the turbine side went down, so the difference changed. Up or down, watever.
The oil feed line comes from the oil filter housing where the oil pressure sender was, the sender was moved to an unused port in the same area. The '96+ engines have two common ports there. I haven't done any more work on the car, but measuring the oil pressure at the turbo is the next step.
Here are a few articles that I found informative:
http://www.approvedturbo.com/troubleshooting.htm
http://www.majesticturbo.com/inside.html
In any case, the oil pressure on the bearing side of the seal stayed the same and the pressure on the turbine side went down, so the difference changed. Up or down, watever.
The oil feed line comes from the oil filter housing where the oil pressure sender was, the sender was moved to an unused port in the same area. The '96+ engines have two common ports there. I haven't done any more work on the car, but measuring the oil pressure at the turbo is the next step.
Here are a few articles that I found informative:
http://www.approvedturbo.com/troubleshooting.htm
http://www.majesticturbo.com/inside.html
-
Shaun41178(2)
- Posts: 8483
- Joined: Fri Nov 19, 2004 7:12 pm
- Location: Ben Phelps is an alleged scammer
I fabbed an oil tank 3" dia. x ~6" tall with a K&N breather on top. The tank is mounted directly below the turbo so the drain hose is only ~4" long.
An electric oil pump sucks the oil out of the tank and puts it back in the engine through the same fitting I previously had in the timing cover. The oil pump is on a relay that closes whenever the engine has oil pressure.
I'm using a Flojet 2100-734 pump, this is the same as the Tilton 40-525 or Mocal branded oil pumps, but slightly less expensive from the manufacturer. Viton diaphrams and valves, fan cooled, self-priming to 8 ft of vertical lift, 2 GPM flow, and able to run dry.
Problem solved, no more smoke.
An electric oil pump sucks the oil out of the tank and puts it back in the engine through the same fitting I previously had in the timing cover. The oil pump is on a relay that closes whenever the engine has oil pressure.
I'm using a Flojet 2100-734 pump, this is the same as the Tilton 40-525 or Mocal branded oil pumps, but slightly less expensive from the manufacturer. Viton diaphrams and valves, fan cooled, self-priming to 8 ft of vertical lift, 2 GPM flow, and able to run dry.
Problem solved, no more smoke.
-
Shaun41178(2)
- Posts: 8483
- Joined: Fri Nov 19, 2004 7:12 pm
- Location: Ben Phelps is an alleged scammer