ok i had my oil tested by the turbo shop as we are going to be puting a single on my car, now i had my twins rebuilt by them twice and they are real smoky (oil) because the bearing in the turbo is worn. they are paying four it all but they want me to sort this **** out. now they say that the 5% fuel dlluion in the oil is causeing the bearings to wear, and they dont want to but on other turbo. i think its **** all, and my factory twins lasted 10years so the new one wont be under warrnty anyway. and i can tune it up with the fc once i get the car back so its not running so rich. so is there anything alse that could be makeing my car do this, and what can i do?

 

your always gonna get fuel in the oil in a rotary, theres really no way around it. as far as the 5% number, i don't know exactly what is "normal" but to me it doesn't sound like that bad of a number? curious what hte other replies on this will be

 

yea thats what i think, i think they are trying to find a way out, they've already spent $1500nz on it.

 

Your oil likely has high level of small metal particles that are causing the wear. I don't think the slight fuel dilution would do it on its own. You have to have something getting in between the metal surfaces and wearing them away. That is why you have higher higher Lead also, from wear of the main journals. A good oil analysis would give you particulate levels-- in particles per ml, or ISO codes, not just PPMs of wear metals.

These engines hold old oil in the rotors and oil cooler/lines. The oil stays in there after a normal oil change. You need a fine bypass filter and let it recirculate to get out the small particles that wear the journals on the turbo bearings. Basically your taking a small flow off the main oil flow and going to a finer filter. The problem is that once the wear starts it just causes a chain reaction and more wear particles are generated from more wear.


That is why the first turbos lasted ten years-- then things started going bad and got worse--- and the metal particles are still in there and the new turbos will have short life. Unless you clean in up. Don't ask me what filter to use since that depends on where you are and what you want to spend. I used a very high efficiency filter that you can't get your hands on easily and they are very expensive.

Get someone with a microscope who can show you whats in your oil.

Most people don't want to hear about this and maybe rightfully claim FDs have bigger problems, but this is one none the less.

 

there likely isn't even a problem with the turbos, generally people overlook high oil pressure.

now, what is your oil pressure at when boosting? cruising? any mods to the lubrication system that you know of?

turbo drain issues can cause higher than desired oil pressure at the turbo and can cause them to smoke after some time.

blockages in the PCV system can cause too much crankcase pressure which will cause the oil pressure the turbo sees to rise above desired levels, this will usually be accompanied by oil leaking externally off engine gaskets as well, usually the front cover is first to go.

 

Would high oil pressure lead to failed bearings or just leakage?

Did the original thread starter see smoking at start up or other signs of wear/leakage of the turbo bearings?

 

5% dilution isn't bad... unless you changed the oil the day before you sent in the sample. lol

A snip-it from a good thread: https://www.rx7club.com/showthread.p...=fuel+dilution

from member turbojeff...

"I bought my 93 R1 with 36K miles. Oil has always smelled like gas. I doubt the motor was worn out with only 36K. I've sent 4 different samples to Southwest Spectro Chemical for analysis, 10% fuel dilution everytime.

I change the oil every 1500-2000 miles with 20W-50, the car has 62K miles on it now.

All the other FDs and TIIs I've owned also had this smell. It seems completely normal.

Since Rich didn't have his oil tested maybe his was worse with the bad side seals, maybe 20% fuel diluition, I dunno."

 

no my car never smoked when i first got it from japan. then i lost my second turbo, got it rebuilt, and they were wost, white smoke everywhere, so we took them off and got it done again, and now its oil smoke. so now we are going single, but the shop is just trying to make sure there is nothing wrong with my car i guess, so im not back there in a few months asking four an other turbo. and my oil pressure was fine, but i was talking to a good mate last night as the shop that took the turbos off the first time twisted a oil line, i have since but a new one in. but he thinks that could have done the wear, as the turbos where not getting enough oil, that cause the wear and now the new on is giving them oil and is leaking.

thanks four your guys help