2x0

I have what I was told is a Precision gt3255e with some porting work done. I haven't actually taken it off the car to investigate yet, just checked shaft play and it feels solid, spins nice.

Problem is I leave oil spots everywhere and they appear to be coming straight from the turbo housing. I resealed the return line flange but it drips from the bottom of the compressor housing, runs down the return line, and burns on the exhaust side.

The exhaust doesnt smoke. There's no leakage on the top by the feed line. But I can smell oil smoke badly inside the car, like it's burning on the exhaust side external to the turbo.

Does this sound like just bad seals? Where do I even go to have something like this rebuilt, and how much is it gonna run me?

motoxxxman

turbo seals don't go bad. either the bearings are shot, or it's getting fed way too much oil, or the drain isn't draining well enough

2x0

What size restrictor fitting should I be using with this turbo?

I am using 0w-40 synthetic and it pushes 75psi cold and 25psi hot at idle. I am not sure what restrictor it has currently.

The drain line is as good as its gonna get.

boosted94gsr

Journal bearing restrictor .065" and ball bearing .035" That's what I've done on every turbo Honda I've ever owned and never had a problem.

TheShodan

iTrader: (14)

That, you'll need to know.. Type of restrictor & size.
That may man you need to remove it and show us, sir.

2x0

Alright I finally investigated the oil feed system. The line comes right off the back of the block and to the turbo, I couldn't find any additional restrictor or fitting on the line.

However, looking into the end of the feed line, it has a small orifice. Doesn't look any bigger than 0.1", probably less, but I've no way to measure it down in there.

Then theres the fitting on the turbo itself, which has a larger orifice. Both are pictured below.

So what do you think, should I try adding a restrictor?

Feed line, can barely see but there's a small orifice down in there.
On the turbo, maybe a .13"ish opening.

TheShodan

iTrader: (14)

That is a restrictor-styled flange that is bolted to the turbo inlet. One of the worst restrictor setups ever. You may have ruined the turbine shaft already by using this thing which makes changing the oil sealing rings worthless. :-(.

You can take the flange off the turbo and try and use the proper restrictor, but at this point, you may need to send it in somewhere to be fully inspected for turbine shaft damage depending upon how long the smoking issue had occurred.

So, you may be beyond a "rebuild kit", and you may not. But those styled restrictors starve the turbo horribly.

Time to send it back to Precision..... Yes, and ONLY PTE.

2x0

This setup has roughly 7,000 miles on it. It does not actually produce oil smoke out the exhaust, at least not enough to be noticed. The biggest symptom is a slow leak, leaving a couple drips below the housing when parked, and a minor burnt oil smell inside the car.

Any idea what size fitting I need to use for this turbo, 1/8" NPT?

Thanks for all your help!

TheShodan

iTrader: (14)

Ok.You still may have time to save it, but get that damn thing off now. More than likely a 1/4npt

2x0

Will do, sir.

LightningTeg

This **** should be stickied

https://honda-tech.com/forums/forced...p5858-3278424/

2x0

Found a lot of good info there, thank you for that. This explains why when I took the feed line off, a terrible burnt smell came from within.

Does anyone know where I can find the proper thread size needed to go into the Precision GT3255 turbo? I have been searching all morning, have found not a lot of good information on this.

TheShodan

iTrader: (14)

You're not going to find it. It depends upon the year that your particular GT3255 was manufactured. (Which you won't really find except through the old catalogs). As when it was mainly used, it was from about 2001-2006, when it was still a Garrett-based unit. But after 2007, you weren't really sure. I can remember that from 2007-2010, PTE based a lot of their CHRAs that they had done on older Garrett & Turbonetics CHRAs , in which 90% of the oil-cooled only CHRAs were 1/4NPT. That's why I stated it earlier.

The best way to check is to take the CHRA to the hardware store, and find a male fitting in both sizes to see if they have the same pitch to confirm. Either way. Turbo has to come off. What you're more than likely smelling is oil on burnt/compromised metal. that's not a good sign. If the shaft is "blued" in anyway, the shaft is compromised at the molecular level (warped) and is about dead anyway. By the time you find another shaft/exhaust wheel to fit, you might as well get another turbocharger.

Example.



That's a good indication that it's done for. But you must take that apart to confirm. If it's a normal "oil" smell, and not foul "oil smell", then you may have saved it. If it basically "stinks", well, you may have already killed it. Just be mentally prepared to get a new unit.

2x0

Thanks Shodan,

I am prepared for whatever it takes to make things right, it's just a matter of working down the list of larger problems to smaller ones. If that means a new turbo, so be it, then that's one less thing I need to worry about afterwards. It also means that it will be more time before I am ready with the funds to throw down on a bigger purchase like that.

The smell was pretty harsh. I've had turbos in the past with bad journal bearings, and have been subjected to more than my fair share of burnt oil fumes of all sorts. This wasn't anything like that, it has burnt oil undertones but there's something else to it. Stings the nostrils.

I personally have only put a few hundred miles on this car in this past year that I've owned it. Every piece of the build and every new problem are things I've inherited and that I am discovering as I slowly rebuild it. That being said, I got the whole car pretty cheap so it doesn't bother me knowing I'll need to redo most of it, that way I can at least do it right this time.

Any issue if I throw a proper restrictor fitting on the turbo and continue to drive it occasionally until putting it away for winter? Will I risk getting metal debris into my oil from the bad shaft?

If I have to pull the turbo to inspect, that means pulling the radiator and a lot of things just to get it out, which will be a winter project for me. I just put a new clutch in and was hoping to at least get it broken in this season, but if it's too much risk with a bad turbo then I guess I will just park it for now.

Thanks again,

TheShodan

iTrader: (14)

If it's stinging the nostrils, I'm gonna be honest, I think its done. The number of miles has very little to do with the fact that its now starved. It's the fact that it had the wrong equipment on there in the 1st place.

People forget that even after slowing down to a light, the turbine is spinning in excess of over 30,000rpms! When you combine that with inconsistent low oil pressure where the oil is no longer filling the cavity of that flange-type restrictor, and the oil is only dripping into the oil channel to lubricate the shaft and journal bearings, (especially in stop/go situations like "daily driving") that spells big trouble. But there's nothing wrong with removing the turbocharger and sending it to Precision to confirm.

At least you'll know your options then. I look at this from a general "here's what most Honda guys have done, when they've thought like you do, and this is what resulted" POV, and seldom optimistic.

You can try using the correct restrictor, but really, I think the damage is done. Driving the car at all at this point just makes things worse.

You can't fix it with a new part if the damage from starvation has already started . The shaft won't transfer any metal shavings to the oil itself, but the shaft will seize, and that can cause the thrust bearing to score the area where the shaft meets, toast the bearings at the same time the thrust bearing is scored, which would cause an imbalance of the shaft as its rotating, thereby bending the compressor wheel , possibly creating pieces of compressor wheel to break (depending upon the material) and both putting debris into the intercooler outlet piping while simultaneously scoring the compressor cover to the point where it is worthless.

Basically, a catastrophic effect

So, you'll go from possibly a reasonable rebuild and repolish of the turbine shaft (if the damage isn't severe), to complete catastrophic failure where only the turbine housing will be the only salvageble item (if your new Supercore will fit it), just because you feel that you want to continue to drive the car just a weee bit longer.

Knowing this information now.... (and you don't have to answer this publicly, if you don't want to) Do you think it's worth continuing to drive with this on, just a little longer?

2x0

To be honest, I probably wouldn't bother rebuilding this one anyway if it has damage, and would just wait and get a new GT3076R or something..... So....

I'll think about it.




The turbo right now has very little shaft play. So if/when this catastrophic failure happens, it'll be pretty noticeable yeah? Audibly or otherwise?

As long as it won't destroy my engine I'm not too worried about driving it. I will pull the turbo to inspect as soon as time allows.

ESP.net

From my experience Precision JB line needs a restrictor. I am on a -4 line and a 060 restrictor. I see 90-95 cold at motor and 20-25 warm. At the turbo I put a gauge in and saw 65 at cold. From my thoughts and experience want to see 60-65 at turbo cold/peak.
So I would throw in a .060 see if smokes or smell and leakgage of oil disapates.

9TechNine9

My $.02
Pull that sucker man. No need to keep driving on a ticking time bomb. Minnesota's driving season has like 3 more weeks, maybe.. Take your time on it over the winter to go through everything and reap the benefits come spring.

P.S.. been lurking your build, keep at it man!

2x0

Thanks for the additional input guys, I appreciate it.

Idk, it probably is already toast. It's lasted 7,000ish miles, if I drive another 200 to enjoy my new clutch and driving the car for the first time when it feels like it's not going to fall apart, that may be worth the risk

If I can at least get the right restrictor on it right away so it is oiled properly and slow the damage that is being done, it'll give me some peace of mind. The more I think about it, the more I would like to redo the entire turbo setup and do it my way anyhow, so I don't want to put a lot of time or money into this turbo if it is already damaged.

I found the restrictor fitting and adapter I need, just gotta figure out whether my feed line is -3 or -4.

ESP.net

Yea do not go -3 .060 restrictor.... get a -4 line... it is what that turbo needs in the first place not a -3...

TheShodan

iTrader: (14)

Again. "shaft play" will not always be a symptom of damage when it comes to turbos. There could be engine damage if debris from the compressor or turbine reaches others areas. No one can give percentages of this.

Be smart. Stop driving this car and remove the turbo.

2x0

If there is risk to the engine then that's a different story, and I definitely won't be driving it then. Will pull the turbo on friday and inspect if that is the case

Thanks. Any quick and easy way to measure the feed line and tell if it is -3 or -4?

9TechNine9

-3an = 3/16" OD
-4an = 1/4" OD
AN Fittings and Stainless Steel Lines

TheShodan

iTrader: (14)

That is incorrect information. Ask the number of people using a -3AN line with that restrictor size on this and about 2000 other builds. That is a common correct size when oil pressure is to be regulated to about 40psi of pressure from 70-75psi at WOT.

Even the older guidelines show that to be the case. (See pg 3 of the attached PDF)

http://speedtrappconsulting.com/imag...ide%20info.pdf

It's the type of restrictor that is the issue here. Not the size line, nor the aperture opening for a Garrett or Turbonetics turbocharger. Even the BW larger series can use that size line.

2x0

This is very helpful info. I forgot to go out and measure mine this morning, but it looks small compared to what I've used in the past, I am guessing it is -3. Since for hose, those measurements are I.D., then I would assume the O.D. for -3 hose would be 1/4 or 5/16.

It sucks I only get a couple hours a week at best to work on this car, so I may not be able to give an update on the turbo condition right away, but I will try this weekend if it comes out easily. I am thinking I can just take a couple of the radiator mounts loose and be able to get it out of the way enough to drop the turbo...

Also I have never disassembled a turbo before, anything I should be extra mindful of during the process? Other than marking how it is clocked currently.