Black oily residue from the exhaust pipe - Isuzu 6BD1T

Jon-d, it is preferable there is little but in reality there will be a little if you only try it wiggle the compressor end.
Correct way to check the bearings is with a dial mic through the oil drain port and lift both the compressor and turbine at the same time

Wiggling one end will tell if the blades are touching the housing. If so time to rebuild.
Cheers Steve

Hi Gents
I'll check again at the weekend for movement to ensure the blades are not touching the housing.
Is it difficult to remove the turbine side for access? The compressor side is easy as. Also, if I can test as you suggest, should there be any movement at all?
If this all checks out ok, where else should I be looking of lack of pressure.
Thanks as always
Ash

Does it blow smoke under load ?

Does the smoke cleat as boosy is made ?

Paul

Hi Paul
It blows black smoke/soot under load Let's call this 10/10. When cruising along with minimal boost, say 1 to 2.5 psi, I'd rate soot at 3/10.
With no boost rumbling along, soot = 2/10.
Hope that makes sense. Just trying to give some sort of ratio to it all.
Cheers
Ash

Oily carbon and soot may be blocking the muffler........backpressure will cut turbo output..........I have also seen exhaust ports in a head nearly blocked,but only with faulty injectors..................there is another possibility I have seen.... a very badly worn camshaft and lifters........wear caused by a broken oil pump relief valve spring.,starving the cam and rockers of oil.

Hi John
Thanks for that. Might be worth looking at replacing the muffler. I'm sure it's been there for quite for time i.e many years.
Might also be worth getting the injectors done too. As for the rest I hope there isn't too much else or she might need a full rebuild at some stage.
I appreciate your input.
Regards
Ash

The worn cam and lifters was a tricky one......but obvious when the motor ran with the intake manifold removed..............air was blowing back out of ports.........and apparently ,the overlap of inlet and exhaust was so long that all the boost air just went thru the cylinder out the exhaust.........no boost ,black smoke,but the motor ran ok...........it was a John Deere ,and they were well known for breaking the relief spring...............oil pressure wasnt low though,as someone had stretched the broken spring to kinda work.

The oil pressure gauge reads around 45psi when cold, but soon drops to about 30psi and that’s where she stays. Has done this since I’ve owned it and the soot problem has only just started so I don’t believe this would be the problem.

Fingers crossed I’m not looking at a worn cam etc.

Regards

Ash

Ash,
Have you tried any injector cleaner?
Now before anyone arc's up I am no fan of snake oil peddlers either.
My long departed Uncle had an Allis with a 426 HP twin turbo six in it, when he saw it punching out smoke down the paddock he would go dose it with Case cleaner. Couple of hours later no smoke. That stuff worked.

On the turbo you only need to pull the air intake to check if the compressor wheel spins free and is not touching. No need to mess with the exhaust. On the movement Jon d is correct if it has ball bearings and not the bushes. Very minimal movement with the ball set up.
Cheers Steve

I put a dose of injector cleaner into Lorry 2 a year. It was not blowing smoke back then and still doesn't. My thinking is prevention rather than cure. Interstate driver across the road said put a litre of petrol in it and that will lift it. That won't be happening.