Oil in the compressor

[Rosco]

Hi all,

Any experts out there, or anyone that knows one, some advice would be appreciated.

I have a Garrett T28 ball bearing turbo on the Busa.

Ever since I had it installed I have been getting oil pooling in the compressor section.

The unit was new, has a scavenge pump that is working and the supply line comes from the oil pressure test plug.

The worst thing is that when I park it tends to leave embarrassing little puddles from the wet K&N filter.

Further, after riding for 30min or so I have little black oily spots all over the ass of the bike.

I just had to change the plugs after about 700miles, it started running like a tractor and the plugs were fouled. New plugs and all better for the time being.

I just installed a BOV (see pic below) but have had to block off the vac line as it now blows oil spray over my radiator and inner panels.

I don’t know if the turbo is getting too much oil pressure or if the seals are screwed or what.

It doesn’t blow any white smoke so I’m assuming the turbine seals are fine.

Does anyone else’s behave like this? Any ideas?

All help appreciated.

Cheers
Ross

 

[nitrousjunkie]

Bearings and seals need to be replaced,there is a turbo refurbishing company in South Carolina.

 

[Gary Evans]

See this explaination.

http://tinyurl.com/75x24

 

[Rosco]

Thanks for the feedback fellas.

Cheers
Ross

 

[Uncle Bob]

doesn't sound like a drain back issue (although that could easily and cheaply be fixed with a couple one-way valves) since its also being a problem while running, not just while parked. Either your scavenge pump is too small for this setup, the lines to and from the scavenge pump are too restrictive, or/and you might want to consider an oil restrictor, although I'd make that a last resort. Oil restictors are usually a bandaid for other problems.

I'm not very fond of electric scavenge pumps because they fail too often. Even if its still pumping, that doesn't mean it hasn't failed. Diagnosing it might be a challenge though.

the other solution to a scavenge issue that isn't mentioned much is a vent line. Can greatly help the scavenge pump work more effeciently, it also reduces the load on the pump, helping it last longer. If you post more pics/data on your return system, I could offer some advice on that.



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[Rosco]

Hey Uncle Bob, thanks for taking an interest.

For some more pics have a look down the page for "Pics of my turbo mods", there not the best views to show problems but they might give you an idea. I'll have to pull the fairings for some more shots later.

I'm starting to wonder wether a check valve after the scav pump might be worth a try. The thing is the return line goes up over the gearbox at the rear of the motor and around to the other side of the engine and feeds into the top of the clutch cover next to the oil filler. Possibly the oil that dosnt get over the gearbox drains back overnight?

I have also had suggestions that crank case pressure can sometimes cause problems and replacint the filler cap with an extra breather may help.

I read on a turbo car site that garrett recomend 10psi at idle and 30psi loaded, I wonder if thats right as the busa pumps up to 70psi when its wound up.


Thanks
Ross

 

[Uncle Bob]

the check valves will only prevent it from smoking on start up, it won't do anything about smoking while riding. As for smoke on start up, remember that your feed line is just as crucial as the retun line, as far as oil bleeding back into the turbo. I put check valves on both sides of the turbo when I mount it low.

All motorcycle run pretty high pressure, I've never seen it cause a problem. The turbo bearings are pretty restrictive and will only allow a small amount of oil through regardless what pressure you have on them. (within reason). Granted, I've never had a ball bearing turbo, but I'd be surprised if it was any different.

 

[Rosco]

Thanks for the advice, that catch can under the turbo on your latest project looks like a good idea, I imagine it allows room for the turbo to drain after shutdown and would help with any oil surges.

Would you mind explaining your scav pump breather idea.


Cheers
Ross