Oil control rings shot?

[Pete_89T2]

My FC is giving off an oil smoke screen under certain conditions, and I suspect the oil control rings may be the culprit. Before I even consider cracking open the keg, I wanted to get some confirmation from the forum. Here’s the pertinent info about the car, symptoms and what I’ve tested so far to draw my conclusions:

Basic facts:
• ’89 T2, running a Hayes rotary crate rebuild motor that I installed in 1999, that now has almost 60K miles on it. Runs very strong, good compression & starts every time. Not a daily driver, but weather permitting I’ll take it for a romp every weekend.

• Turbo is a BNR Stage 1 rebuild, that I installed in early 2011, it now has about 5~6K miles on it.

• Installed the RA-OMP adapter to run premix thru the stock OMP system last winter, have about 3000 miles with that setup.

Symptoms:
• While accelerating moderately hard, I’ve seen smoke out my rear view mirror start to become noticeable at around 5K RPMs and up. It’s definitely oil smoke - bluish in color with that acrid stink. If I abruptly let off the gas, while keeping the car in same gear to keep the revs up, the smoke cloud gets VERY dense. So the smoking seems to get worse while decelerating or holding a steady speed at a high RPM (off boost) that it is while accelerating/boosting.

• If the car sits for more than a few days between starts, on the next startup I’ll get a short lived cloud of oil smoke as the car idles. Smoke is gone in less than 10~30 seconds, a bit longer if the car hasn’t been run in weeks. I think this particular symptom has something to do with my RA-OMP adapter setup, as I’ve noticed the level in my premix tank drops slightly even when the car just sits in the garage unused for a few weeks – I think some premix is gravity feeds itself into the keg, and that oil gets burnt up on 1st start.

Things I’ve tested/checked out so far:
• Had a friend follow me on a few runs to confirm what I was seeing out the rearview mirror – no doubts there, symptoms above are confirmed.

• Opened up the intercooler piping to look for evidence of oil. IC piping & rubber elbows had some oily film, but no pooling of oil anywhere. Not enough here in my judgment to convince me that oil is getting sucked in via the turbo compressor side, given how long it’s been since I last cracked open the IC piping and the # of miles I put on it since then.

• No visible leaks anywhere, oil or otherwise.

• Tested the Purge Valve/PCV per the FSM procedures, and it is working properly.

• Ran the test on Ted’s FC3SPro website where you rev the car up to 3~4K RPMs in neutral and hold it at that RPM for 10~15 seconds or so to see if it smokes. I had no smoke visible up to 4K RPMs, even after holding it there for 30+ seconds. No smoke when I let off the gas either. Repeated this same test, but with incrementally higher RPMs each time, and held it there for about 15 seconds. Starting at about 5200 RPMs, the smoke came back after about 10~15 seconds of holding it at that RPM. At higher RPMs, the smoke cloud just gets thicker, and it becomes visible earlier in the “hold” period.

So what do you guys think? Anything I missed here?

[RETed]

Pull the spark plugs...
Does the plugs look like excessive oil?

If it doesn't, it sounds like turbo turbine seal is bad...


-Ted

[Pete_89T2]

Pull the spark plugs...
Does the plugs look like excessive oil?

If it doesn't, it sounds like turbo turbine seal is bad...


-Ted

Good idea. I'm taking off work starting Wed, so I'll pull the plugs then and take a look/snap some pictures. IIRC, plugs last went in last spring before DGRR, so they have about 3~4K miles on them now.

[mazpower]

Try pulling your downpipe and check the color of the turbine. Brown/tan is normal, an off white is indicative of oil burning from the turbine seals.

[Kentetsu]

Increased smoke on deceleration is a classic symptom of blown oil control rings. I'm not very knowledgeable in regards to turbos though, so there may be something related to that whole system.

If it is the oil control rings, you can get very good results with Lucas Heavy Duty Oil Stabilizer. My old 12a was leaving a smoke screen, which was 95% alleviated by running a quart of the Lucas in the oil. Put about 30k miles on that motor until it coughed up an apex seal at 213,000 miles.

I still use Lucas in my current motor just as a preventive measure...



.

[Pete_89T2]

Well here's a picture of the plugs. No evidence of wet oil anywhere when I pulled them. Probably hard to tell in these pictures, but color of deposits is a black to brownish and have a sooty texture to them - running my finger over them it feels like 1000 grit sandpaper, and some of the carbon residue transfers easily to my fingers. What do you guys think? Probably should pull the DP to take a peek at the turbo turbine wheel next.

http://www.rotarycarclub.com/rotary_forum/attachment.php?attachmentid=12587&stc=1&d=1353515572

[RETed]

Spark plugs looks pretty good...

Blame is starting to shift toward the turbo turbine section.

Just to eliminate the easy stuff...
Stock turbo drain assembly?
If it's been replaced, what size fittings and hose?
Relocated drain point back into sump?

PCV system still intact?


-Ted

[Pete_89T2]

Spark plugs looks pretty good...

Blame is starting to shift toward the turbo turbine section.

Just to eliminate the easy stuff...
Stock turbo drain assembly?
If it's been replaced, what size fittings and hose?
Relocated drain point back into sump?

PCV system still intact?


-Ted

That's what I thought about the plugs too, pretty normal wear & tear.
PCV is fully intact and verified to work per FSM procedure. I did have to modify the stock turbo drain to solve an interference problem with my RA OMP adapter. It uses -10 hose & fittings, retains the stock return point on the front cover and is routed almost the same as stock. Compared to stock, it takes a bit of an arc away from the block, but the plumbing has a downward slope the whole way back to the front cover. This thread has a photo of it, see post #6

http://www.rotarycarclub.com/rotary_forum/showthread.php?t=14945

[Pete_89T2]

Resurrecting my old post. Those of you who were behind me a DGRR this year were treated to the smoke screen. I finally got around to pulling the DP and taking a look at the turbine wheel...

Try pulling your downpipe and check the color of the turbine. Brown/tan is normal, an off white is indicative of oil burning from the turbine seals.

Here's some pictures, I'm thinking shot turbine seals now, what do you guys think? Definitely white/off-white color deposits.

http://www.rotarycarclub.com/rotary_forum/attachment.php?attachmentid=13390&stc=1&d=1372715987

http://www.rotarycarclub.com/rotary_forum/attachment.php?attachmentid=13391&stc=1&d=1372715987

http://www.rotarycarclub.com/rotary_forum/attachment.php?attachmentid=13392&stc=1&d=1372715987

[Rotary Evolution]

nm, clipped wheel and angle made it look odd.

check the shaft for thrust play and excessive side to side play indicating worn shaft bearings and/or worn thrust plate.

Bryan also removes the oil restrictor to the compressor assembly which sometimes causes blowby issues even in the turbine section. you can run a restrictor to the oil feed if you have any oil pressure modifications or lacking crankcase breathers.

[Pete_89T2]

nm, clipped wheel and angle made it look odd.

check the shaft for thrust play and excessive side to side play indicating worn shaft bearings and/or worn thrust plate.

Bryan also removes the oil restrictor to the compressor assembly which sometimes causes blowby issues even in the turbine section. you can run a restrictor to the oil feed if you have any oil pressure modifications or lacking crankcase breathers.

Sorry for the crappy pictures, was tough to get a good focused shot from laying on my back under the car. I checked the shaft for play by hand, no thrust (end-to-end) or side-to-side play that I can feel, but the shaft rotates freely without any binding.

Didn't know Bryan removes the oil restrictor; would that be an issue with a stock oil system? I have no oil pressure mods. Also, the car is using the stock crankcase ventilation system, which was tested per the FSM and found to be working.

[Rotary Evolution]

the stock crankcase vent system is fine for stock boost levels, beyond 10 psi even on a hybrid i would recommend opening it up to vent to atmosphere via a breather tank.

[Pete_89T2]

the stock crankcase vent system is fine for stock boost levels, beyond 10 psi even on a hybrid i would recommend opening it up to vent to atmosphere via a breather tank.

I still have the stock ECU (w/Rtek 2.x mod) controlling boost, so boost pressures are limited to S5T2 stock levels - I never see more than 8~8.5 psi in the Rtek data logs or on the boost gauge. And with the BNR waste gate porting, this setup is well controlled, it never spikes or creeps upward beyond those levels.

Given that, I'm not sure what benefit I'd get from switching to a catch can/breather tank crankcase vent, other than keeping a little oil film out of the intake plumbing & IC.

[RETed]

There's no reason to be running some catchment system on a street car, no matter how much power or boost you're running.
You just can't run the car hard enough on the street to see an advantage to such system.
Catch cans can cause more mess in the engine bay due to it's design...

The pics of the turbine wheel aren't detailed enough to show any obvious problems...
The color is actually right for a normally running engine.
Maybe you can get some black crud to fall out of the turbine housing by tapping on it with a hammer?
Most likely you have blow-by from the turbine compression ring, but it may not be obvious until you pull the entire turbo apart...


-Ted

[Pete_89T2]

There's no reason to be running some catchment system on a street car, no matter how much power or boost you're running.
You just can't run the car hard enough on the street to see an advantage to such system.
Catch cans can cause more mess in the engine bay due to it's design...

Yeah, I agree.

The pics of the turbine wheel aren't detailed enough to show any obvious problems...
The color is actually right for a normally running engine.
Maybe you can get some black crud to fall out of the turbine housing by tapping on it with a hammer?
Most likely you have blow-by from the turbine compression ring, but it may not be obvious until you pull the entire turbo apart...


-Ted

Wish I thought of the tapping it with a hammer trick while the DP was still off :banghead:

[Pete_89T2]

An update... This past Friday, I took the car to Speed1 to have Dave B. take a look and give me a professional assessment of what is going on. Bottom line is the turbo is starting to fail, and it will get progressively worse. Ted nailed it with the failing turbine seal diagnosis.

While I'm happy that the engine itself is healthy, and won't need to be cracked open for a long time, I'm pissed that this turbo is failing prematurely. Like I said before, it's a BNR stage 1 rebuild, that I installed & fired up for the first time on 3/11/2011, and logged only 11,889 miles on it since then as of last Friday. And since I'm running stock boost control, it was never pushed beyond the stock 8~8.5 PSI boost pressure limits. Hell, the stock turbo had 136,XXX miles on it when I shipped it off to BNR for the rebuild, and it didn't smoke anywhere near as bad as this one does now.

[Rotary Evolution]

just mark the wheels and rebuild it yourself, you can do it for under a hundred bucks.

[RETed]

If you ever messed with that darned turbine compression ring seal, you'll know that it's a nasty design.
Out of all the nice Garrett (rebuild) parts, it's one of the worst - the thrust bearing come a close second.

I dunno if there is a trick to get that compression ring seal to install correctly consistently, but I haven't figured it out yet.
You got the blasted exhaust shield bell cup loose and getting in the way, and the design of the seal being square-edged don't help with it going in nicely!
If you end up tapping it in - which is the case most times - it's probably damaged from that light tapping. :(
I use LOTS of oil to try and get the seal to snap into place, and that causes a big smoke show on the initial start up...
This can help sometimes, but it's still not a guarantee!
Then you end up crossing your fingers that the smoke eventually clears up soon!


-Ted

[don3vor]

Pete, what kind of warranty came with the turbo if any?

[Pete_89T2]

Pete, what kind of warranty came with the turbo if any?

It was a 1 year warrantee, don't recall if there was a mileage # associated with that. Given the premature failure, I'm going to see if BNR is willing to cover at least a portion of my costs for a turbo repair. I'll be pulling it out & reinstalling it myself, so no costs there.

[Pete_89T2]

just mark the wheels and rebuild it yourself, you can do it for under a hundred bucks.

I've given a DIY rebuild some serious thought, and if BNR tells me to go screw myself, I just might give it a try.

If you ever messed with that darned turbine compression ring seal, you'll know that it's a nasty design.
Out of all the nice Garrett (rebuild) parts, it's one of the worst - the thrust bearing come a close second.

I dunno if there is a trick to get that compression ring seal to install correctly consistently, but I haven't figured it out yet.
You got the blasted exhaust shield bell cup loose and getting in the way, and the design of the seal being square-edged don't help with it going in nicely!
If you end up tapping it in - which is the case most times - it's probably damaged from that light tapping. :(
I use LOTS of oil to try and get the seal to snap into place, and that causes a big smoke show on the initial start up...
This can help sometimes, but it's still not a guarantee!
Then you end up crossing your fingers that the smoke eventually clears up soon!


-Ted

And this is exactly the kind of stuff that worries me about trying to rebuild it myself... Good info here Ted, I've done some web surfing and watched maybe a half dozen "how to rebuild your turbo" vids on Youtube, and naturally none of them covered these "gotcha's".

[Rotary Evolution]

it helps if you orient the gap facing the topside of the CHRA, gravity you know. while i also bead blast the turbine wheel i do not touch the shaft, i let it soak in a carb cleaning bucket for a day then scrub it by hand. and sometimes you just get junk seals.

[Pete_89T2]

In the event that BNR doesn't assist with my turbo rebuild, can anyone recommend a good parts source for a full turbo rebuild? My understanding is that my BNR stage 1 turbo I need to rebuild can use a rebuild kit made for the stock Mazda S5 turbo, which is a Hitachi HT-18. The HT-18 uses Garrett rebuild parts in the CHRA. Found this kit on the net:

http://gpopshop.com/products-page/hitachi-turbo-rebuild-kits/hitachi-ht18-complete-rebuild-kit/

Can anyone confirm that these are the correct parts for a rebuild, and if so, would it be advisable to pay extra for the 360* thrust bearing/step-gap piston option?

[RETed]

The Hitachi series turbos can use Garrett T3 / T4 internals.
You should be able to find rebuild kits for "Garrett T3 / T4" turbos no problem.

Be very careful when ordering that carbon seal.
I've had rebuild kits where the carbon seal was loose banging around with all the other parts.
This causes the carbon seal itself to chip and end up basically useless.
Good vendors would carefully package the carbon seal separately.

The 360-degree thrust bearing would be used for higher boost.
I would not bother with it unless you're shooting for over 10 - 15psi of boost on a consistent basis.
Also, having a good (i.e. brand name aftermarket) BOV helps here.

The stepped piston ring is recommended if the price isn't that much more than the regular one.
I've had those things leak before, so they are not that much better than the regular butt joint ones.


-Ted

[Pete_89T2]

Hey guys, after lots of back & forth emails with Bryan at BNR, I was offered a deal to consider for rebuilding my BNR Stage 1 turbo. My other option is a DIY rebuild. Below is a description of each option, and the pros & cons of each one from my perspective. Would like to hear the forum's thoughts on which option makes the most sense, and let me know if I'm missing anything here:

BNR Rebuild #2 option: BNR is offering me a discount on the 2nd rebuild for my BNR Stage 1 turbo. It will cost me $300 plus shipping, but will include a new CHRA housing and a new turbine wheel/shaft in addition to all the new rebuild components (seals, thrust bearing, journal bearings, etc.) that come with a Stage 1 rebuild. According to Bryan, he doesn't want to reuse my used turbine wheel/shaft and CHRA housing because (a) New parts result in a better rebuild and (b) cost of new parts is comparable to the cost of labor to dissemble/clean/inspect used parts, and that the cleaning (media blasting) process can sometimes render parts unusable

Pros - Comes with new turbine wheel/shaft & CHRA housing. BNR does the balancing, and this a simple remove & replace turbo job for me. Probably a faster turn-around. Total cost isn't much more expensive than a DIY rebuild, assuming I farm out the balancing job to a local turbo shop.

Cons - BNR is not willing to offer a new warranty, and BNR would not tell me the exact source of the new turbine wheel/shaft & CHRA housing - other than stating he is using an offshore manufacturer. I'm a bit concerned that offshore may mean China made parts of questionable quality.

DIY Rebuild option: As implied, I would do the rebuild myself. Never rebuilt a turbo before, but have done a lot of research on the process and feel confident that I can tackle this. I found a relatively local turbo shop in Wilmington DE that works mainly on diesel turbos that can balance my rebuilt rotating assembly for $100. As for rebuild parts, a "high performance" complete kit for the HT-18 (i.e., w/improved turbine seal plus 360* thrust bearing) costs <$120 from a number of online sources. Will go with G-Pop shop as they have comprehensive customer support and I confirmed that they pack the delicate parts correctly for shipping.

Pros - Costs a less than BNR option. Since it's DIY, I'll learn from doing it, and I'll know it was done right and if it isn't, I only have myself to blame. Well not 100% true, as I'll farm out the balancing task.

Cons - Extra time to perform the rebuild and schedule the balancing job. Potential "gotcha's" if I find out after cleaning & inspection that any of the parts I need to reuse are out of tolerance/specification for reuse. As I've had no luck finding a reputable source that sells new HT-18 turbine wheels/shafts this can become a big problem. And if I do need new parts, assuming I can find them, the additional cost is an unknown.

[RETed]

Why don't you try DIY rebuild yourself and see what happens?
It sounds like you're interested in the whole process, and you learn a LOT from doing it yourself. :)

As a fall-back, you can always go BNR if the DIY fails?
$300 is cheap, considering that $100 is going to the rebuild kit itself.
Even a cheapie CHRA is going to be at least $100, so the last $100 is BNR's labor?
That's a great deal...

As for sourcing of parts...
I would worry a little about China, but I would not be surprised...
My Garrett GT-R ball-bearing series turbos all had stickers: "MADE IN MEXICO".
I was kinda pissed my ~$1,500 turbos were MADE IN MEXICO, but what can you do, right?
I know there's a lot of turbo parts coming out of South America (Brazil?) also.
As a side, I think Brembo also has a factory for in South America?

Although not BRAND NEW, there are lots of used HT-18's out there.
It might cost you maybe $100 for one, but the RA's should be in good shape, or at least be minimum rebuildable.


-Ted

[Pete_89T2]

Why don't you try DIY rebuild yourself and see what happens?
It sounds like you're interested in the whole process, and you learn a LOT from doing it yourself. :)

It would be a great learning project, and even if I end up not rebuilding my own turbo, I might just pick up a boneyard turbo off of any car/truck to practice on. Tear down, clean/inspect & reassemble with the same old & worn parts just for practice. Sort of like a doctor practicing surgery on cadavers!

As a fall-back, you can always go BNR if the DIY fails?
$300 is cheap, considering that $100 is going to the rebuild kit itself.
Even a cheapie CHRA is going to be at least $100, so the last $100 is BNR's labor?
That's a great deal...

I haven't asked BNR that question yet, but I don't think he would honor that deal if I DIY'ed it myself first and it failed. $300 is a great deal, and I think he's doing it at that price to stand behind his work and maintain a good reputation. He's basically giving me all the new parts/rebuild kit at his cost, and the rest is labor/profit. Price he gave me on the turbine wheel/shaft was $100, and $65 on the CHRA housing, so the $135 left over covers the rebuild parts & labor. BNR can probably get his rebuild kits for maybe $40~50 each in quantity, as opposed to the $100 I would have to pay retail. The compressor wheel I have in there is practically brand new (<12K miles on it). So by using the new parts, he saves himself a big chunk of his cleaning & inspection labor that he would have incurred to reuse the old turbine wheel/shaft & CHRA housing. That's with the standard rebuild kit though (270* thrust bearing, standard turbine seals); if I opt for the high performance versions it would cost me $40~50 more.

As for sourcing of parts...
I would worry a little about China, but I would not be surprised...
My Garrett GT-R ball-bearing series turbos all had stickers: "MADE IN MEXICO".
I was kinda pissed my ~$1,500 turbos were MADE IN MEXICO, but what can you do, right?
I know there's a lot of turbo parts coming out of South America (Brazil?) also.
As a side, I think Brembo also has a factory for in South America?

Although not BRAND NEW, there are lots of used HT-18's out there.
It might cost you maybe $100 for one, but the RA's should be in good shape, or at least be minimum rebuildable.


-Ted

Yup, the unknown quality of these new offshore parts has me a bit concerned... To mitigate that risk I think I'll just ask him to send my original parts that were replaced back with the turbo. That way if this next BNR rebuild ever does fail, I'll have some spare parts to draw from and use the best/better ones for a DIY rebuild. Agree it's easy enough to find a used HT-18 to use for parts, but you really don't know what you got until you tear it down, clean & inspect it.