z31eric

Hey guys--

Bought a wrecked 87 T2 from a friend w/ 35k orig miles. Transfered EVERYTHING over to an 88 NA

engine, drivetrain, wiring, ecu, associated sensors, etc. Used the turbo harness as I wanted to keep the old engine "intact" w/ all manifolds & such on, so I can put it in another car when I find one, or just sell it, etc.

While the engine was out of the T2, & not yet in the NA, I:

Ported WG & welded washer on

pressure washed engine, & cooling system (rusty!! ), then added new hoses everywhere

had injectors sent out & flow tested, etc

other "good practice" things that take more time on assembly/builds, but make the time take longer

Also installed a boost gauge & wide band, though the wide band (innovate) error'd & I never got an accurate reading

So anyway-

Car boosted great, right around 8 lbs for the first 5-10 miles of driving. No boost creep, no issues, no irregular noises. Then suddenly, there's no boost. I check the WG, it's still connected. Nothing missing hose wise... So I pull off the TID- low & behold the turbo is SIEZED! I can not turn it by hand, at all.

oil pressure gauge read oil pressure the whole time, no leaks. Coolant full & good, no leaks there either.

When I had the turbine housing off for porting, I did notice a crack both on the flange, about 1/4" long, & another around the turbine wheel (see picture, not my pic, but the same type of crack.)

rotating assembly on turbo spun great, though with some slight drag (though this is my first turbo car, so I thought it normal. No grinding or rubbing or anything, it just would come to a stop in 1-2 sec when flicking it w/ your finger while on the bench.

so, my question to everyone, is, what on earth happened?? I'll be pulling this one off soon & investigating. Need a rebuild at the very least, for sure. haha. Would just like to know WHAT failed so I can prevent in the future!

Thanks!

RotaryRocket88

iTrader: (7)

Unless there are signs of the compressor or turbine contacting the housings, the bearings are done. If you disassemble the rest of the turbo, you'll probably find signs of wear and/or blueing of the shaft. It's hard to say what exactly could have caused it until the rest gets disassembled. There may be debris in the CHRA or carbon coking.

Minor cracks in the castings are normal with age. This has been asked 3-4 times in the past 2 weeks.

z31eric

Thanks for the quick reply!

I got my hands on the compressor wheel today once it'd cooled down over night, & I could spin it backward, & then eventually, all the way around both directions. NO scraping in the compressor side at all... Took it for a drive, same thing happened! Pulled the TID AGAIN! got it free again, & it siezed again. . There's got to be something that came off & its binding it & preventing it from spinning. Will pull it tomorrow after work & investigate.

There was no in/out shaft play, & "runout" (up down) was very minimal. Once it spun again it felt like nothing ever happened.

I did spray libral amounts of WD40 into the combustion chambers, as I pressure washed the outside of the engine/cooling passages & didn't want corrosion building inside the engine during the down time.. maybe a bit of debris from in there came out & lodged the turbine. We'll see tomorrow!

arad99

iTrader: (2)

The turbo bearings are probably shot. When they cool down they shrink a little which allows the compressor wheel/shaft assembly to turn but as soon as they get hot again, they seize.