why does my turbo keep breaking

[ghfarm]

I have a 2003 acgo st40 turbo diesel powered by a iseki 40hp. This engine has been a nightmare since I've owned it. It only has 450 hrs on it and the head gasket has gone on it once already and now my turbo itself has gone bad again for the 4th time. The inner propeller in the turbo on all the others ive taken off are all sloppy and worn out. This last one only lasted 30 hrs. Once they go the tractor starts burning the crank case oil up and smokes like crazy and runs ruff at an idle but under a load it runs good but it does smoke. Does any one out there have any idea why I keep burning out these turbo's. Also there is a breather tube that makes it's way down to the bottom of the engine that always has alot of steam blowing out of it and doesn't seem right to me why it steams so much. Not sure if that has anything to do with my turbo issue but thought i'd mention it. I bought this thing with only 45 hrs on it and i have always taken very good care of this tractor

thanks
wade

 

[mrmikey]

Only thing that comes too mind is inadequate(sp) oil flow to the bearings. Do you let it idle for a few minutes after use to allow the turbo to cool down some? If not the oil wil coke and plug the passages....Mike

 

[KWentling]

Did you pre oil the turbo bearings when the new turbos were installed? A dry start would be pretty hard on them. Agree with mrmikey on checking oil flow to the turbo and cool down time. It would seem there is a lubrication problem. With only 450 hours, I wouldn't expect to see much blowby ("steam") from a good engine.

Kim

 

[tcartwri]

Late injector timing will cause the fuel to continue burning in the exhaust manifold and overheat the turbo.

 

[90cummins]

It sounds like lack of oil or dirty oil if the shaft is loose.
First thing to do is check the flow rate of oil to the turbo and thru it.
This can be done by disconnecting the turbo drain and running the engine while catching the oil as it drains from the turbo.
If the oil flow is good check where the oil supply for the turbo is taken, it must be filtered oil that has gone thru the oil filter not before it.
Having performed the above and found no issues I would install a separate filter in the line that goes directly to the turbo. I installed a turbo on my 1720 Ford and used a 10 micron hydraulic filter.

Tim

 

[Redneck in training]

How does the turbo sounds? It should emit nice even high frequency "whine". If the sound is irregular, how can I describe it, similar to clapping, the compressor is surging and will not last long. Make sure that the air filter is unobstructed, valve timing is correct and if it has a waste gate check the pressure setting. As it was already mentioned before injection timing might be also the culprit. If the exhaust gases are too hot or still burning in the manifold the turbo runs faster and supplies more air than the engine can intake. Pressure in the intake manifold could rise too high and also surge the compressor. Surging induces large axial thrust forces that can and will damage the bearings allowing the impeller contact the casing and also overheat the compressor impeller.

 

[schoolsout]

do you use synthetic oil?

 

[KLMandW]

I agree with several of these fellows.....oil is the culprit. Either not enough flow volume....not properly cooling the turbo down after working the engine at load.....or exhaust gas temps getting too high due to timing or fueling problems. If EGT goes over 1100 degrees for any legnth of time you have a mini Cherynobyl on your hands.