Need to tap the resident Turbo braintrust

Guys,
I pulled the pipes, collector box and of course the turbo. The collector had about 2 ounces of clean oil inside. The turbo itself was covered with clean oil/dirt on the outside and also had a coating, nothing more, of clean oil on the inside of both the impeller chambers. I've read that a faulty check valve on the return side will cause the oil to back up and seep past the seals but once repaired, the seals won't leak since they swell with the pressure.

I capped all openings and cleaned the complete outside of the turbo nice and clean, then I reached in each opening and cleaned out any gook. The only place where there was any debris at all was outside the waste gate which makes sense to me.

Once everything was cleaned, I rotated the turbine impeller and I'm willing to bet that if I had a long piece of lead from a #2 pencil, I could have rotated it without breaking the lead. It really rotates that easily. I held the end of a cheapo Craigslist basement vac that cost me 10 bucks and it rotated nice and smoothly and fairly fast. There is NO play either axially or longitudinally….I’m thinking of cleaning out the oil reservoir really well and reinstalling it the way it is after letting it soak in a tub of Whites hydraulic fluid(to renew the seals) for a couple of days while I do the rest of the bike.

What do you guys think? Anyone know how to replace the seals just since I’m already here? Do you think that I need to? This is where I need some input from you guys that have already dealt with this but please don’t toss 2cents in just for the sake of tossing in your opinions unless they’re based on some experience. I’ve disassembled and rebuilt plenty of different engines but never worked on a turbo before so I’m not at my first dance, just need some insight from people that have done what I haven’t.

Thanks guys….

 

The bearings and seals are the same as used in the smallest Mitsubishi turbos, and the parts are readily available, and if it were me - I'd let an experienced Turbo Tech fiddle with it, as it spins at 240,000 RPM.

Or I'd run it as-is and see how the Whites Fluid works on the 28 year old seals. Just don't let any loose rust or debris float into the bearings while you're soaking, scrubbing, and cleaning.

 

I think you have the wrong idea about the seals. They should all be metallic seals, with the shaft seals resembling small piston rings. There is nothing to swell up, as it were. Give it a very thorough cleaning before you re-install it. My turbo would load up with oil if the bike sat for more than a week. It had over 50,000 hard miles on it and the turbo had no play in it at all. I would strongly recommend not spinning it up with no oil going to it. It idles at over 100,000rpm, and dry bearings are not going to last very long at those speeds. If I had another turbo, I would ditch the spring loaded ball check valve and install a Swagelock inline check valve in the oil feed pipe to the turbo, something with a light cracking pressure that can take the heat. Even a small teflon seated poppet style check valve might work.

 

I appreciate the input. I found what I needed earlier this week and got the education I needed on the turbo and the wastegate vs BOV as well. I think I'm headed in the right direction now.

Thanks guys,

jeff