large_x7

iTrader: (1)

Well, I thought I had had a simple (but expensive) problem on my hands: my turbos were finally toast. Car has 110,000 miles, original turbos and engine. Symptoms:

1) smoke out the tailpipe. A lot of it at startup, then down to some puffs after the engine warmed up. Also, big black belches when I shifted at higher rpms.
2) drinking oil. Like a quart in between changes. Although I've always had to add some oil in between changes.
3) finally, low boost. Only hitting about 7-8lbs.

I had searched and the only other problem that causes smoke in the exhaust would be a faulty coolant seal, which would result in bubbles in the coolant filler neck. I checked and found nothing. "Easy!" I said to myself. "I need new turbos!"

Started disassembling everything tonight. Intercooler was filled with oil. "Aha!" I thought. "New turbos for me!" Finally, I took the Y-pipe off, and...there was no oil in the turbo outlets!

How can this be? Shouldn't they be filled with oil? Right now, the outlets are the cleanest thing in the engine bay!! Did I mis-diagnose? Where was all that oil going to? I did notice some oil on the rear engine mount, but I have always had oil there. And I have no idea how it would get into the intercooler? Somebody help me please before I go through the trouble of taking my turbos all the way off. Thanks!

alwan16

well there are three possibilities if you are burning oil out your tailpipe. one, your turbos are going bad. everybody's older turbos blow oil into the intercooler. this doesn't mean the turbos seals are shot between the oil and exhaust housing though. two, your internal engine oil seals are going out. this basically means it's time to rebuild. my guess would be it's the engine that's going out and not the turbos. that is what happened to the last engine i lost. smoked like crazy on startup and when you floored it. there are reasonably easy ways to check this though.

1. remove turbos and look for oil in the housing of the engine. if there is a lot of oil it will be all over the exhaust manifold too. if there is a little puddle in the bottom of the housing you know it's all over.

2. remove spark plugs and stick in one of those fiber optic cameras in. i forgot what they are called but some mechanics have them.

you might look down there and see if there is oil coming out of the spark plug holes too. i drove my engine into the ground because i knew it was toast anyways. there was quite literally oil coming out of those holes.

good luck.

alex

large_x7

iTrader: (1)

what happened to number three?

Okay, I'll check those things. I had actually hoped it was my turbos. A rebuild is a little bit more expensive.

Anyways, for an update: I just took off the rest of the intake piping on the turbos and looked at the compressor wheels. Both wheels look fine (although I have no idea what I'm looking for), but I did see some scoring along the housing, probably from the compressor blades. I couldn't feel any shaft play though.

Also, I did notice quite a bit of oil near the inlet of the primary turbo Is this blow-by from the engine?

Anyways, if my engine needs a rebuild, I'm gonna have to rework my finances and schedule a bit to accommodate this.

Also, if my oil seals are shot, then do recommend letting the car sit until I can get a rebuild, or driving it into the ground (like you did) and possibly risking more damage? What happens (consequences, that is) when your oil seals blow out?

large_x7

iTrader: (1)

Well, I checked the exhaust manifold and it is even cleaner than the turbo outlets! I'll try and research it some more tomorrow; right now I'm going to sleep!

cewrx7r1

iTrader: (2)

From the mileage and age, Do It All!

Have the turbos rebuilt and rebuild the engine.

Doing anything else is just playing games with yourself.

Fresh turbos with an old tired engine is foolish, as is a new engine with tired turbos.

large_x7

iTrader: (1)

Unfortunately, my budget tells me that I can only fix what is wrong.
New engine + new turbos = eating ramen for next six months.

Rotarded

Brian,

I just went through this, twice. My original set of turbos were blowing so much oil that I started smoking after 30 seconds at idle. At WOT, I was throwing more white smoke than a mosquito fogger and having to add a ton of oil.

I ran an oil catch can for a month to see if I was getting excessive oil blown into the intake from the filler neck/PCV. It proved to not be the cause.

I swapped turbos (used) and the smoke at idle was solved. BUT I still had some white smoke at WOT during transition. My blowoff valve was spraying oil down my FMIC piping.

When I removed my FMIC to see how much oil was in it, I was amazed that, for the amount of oil smoke I was blowing/smelling, I did not have a more than a 1/4 cup accumulated in the FMIC.

I removed the turbos to inspect. I was surprised that I did not see anything more than a thin film of oil??

The 2rd set of turbos, as well as a silicone hose job, went in last week and NO MORE OIL SMELL/SMOKE!!!

White smoke that smells like burning oil is just that, oil. White, sweet smelling smoke is coolant.
Black is carbon and usually signifies rich running.

Your poor boost is could be a simple boost leak issue. Let me know your boost pattern, bleed off, and whether your are transitioning!

Mike

alwan16

well if you took off the turbos and the exhaust manifold was clean then it is your turbos. hahaha...i drove my car full throttle up a whole bunch of super steep sf hills and it was burning oil all the way to the top. i got home, parked it and a couple hours later tried to pull it into the garage and it literally had zero power. i barely made it 20 feet.

sounds like just the turbos are bad. try and get a reasonable used set. that would be the cheapest fix.

alex

large_x7

iTrader: (1)

Yeah, that's what Mike (Rotarded) and I decided. After all, he is the blown turbo expert. I'm probably going with a set of BNR upgrades. Going down the RX-7 Store tonight!