['72 Bullet]

Hi all,

Facts

- Year 2000 SUMO
- ~1,24,000 km on odo.
- Been getting black smoke for the past 2-3 months (since getting the turbo over-hauled)
- Till a few weeks back, didn't pay the smoke much notice as engine was smooth, pick-up and torque delivery was good and there was hardly any oil-consumption.
- Now the engine has started making harsh sounds, the pick-up and torque is suffering and it's now giving out clouds of black smoke. It is also now consuming a little oil.
- On asking, the mechanic was muttering about back-compression, any idea about what that is?

Now the question is what needs to be done? Will a change of piston-rings suffice or will I need to go for a complete over-haul?

Looking forward to ideas from all you people.

Thanks in advance and best regards.

[pradipk]

Not guru but I guess with the odo reading you have, over-hauling is required otherwise piston rings change is the standard solution & need for Sumo.

[nitrous]

Your FIP needs recalibration. Costs quite a bit (~10k).
Go directly to the calibration guys like Bosch. Ensure they give you a 6-month service warranty just in case it starts smoking again.

Its also smoking because of the compression loss due to which the engine oil is entering the combustion chamber. Tell us the quantity of oil loss per 500 kms or 1000 kms.

[condor]

What make is the turbo ?
Where did you get the turbo overhauled ?
Was anything else touched ?
Did these problems start after the turbo was overhauled, or were there from before ?

@Nitrous, the FIP in his Sumo is most likely a Lucas. Good idea to go to a TAS.S / Lucas for that part.

[Jaggu]

What was the overhaul done on the turbo? was it completely stripped and fixed back with new parts OR just removed and cleaned and put back.

I also suspect the fuel pump.

[varunroy]

Originally Posted by '72 Bullet

Now the question is what needs to be done? Will a change of piston-rings suffice or will I need to go for a complete over-haul?

Remove the Engine oil Dip stick and watch for smoke coming out of the mouth when you start the engine.If yes, then there is back compression and you may have to change the Piston Rings provided the cylinder liners are good. If not a complete overhaul may be required.

What make is the FIP? Mico or TVS. Overhauling the Mico Bosch should not cost more than 2K while the TVS could cost upto 10K. But I strongly feel that the engine has lost power because of worn out Rings/Piston/cylinders. If you need to overhaul the Mico one, I suggest you get it done at Mangalore. He is a really reliable guy who works wonders on the FIP at one/fourth the cost.

Check out the Major and minor Engine overhaul kits available at TASP. There are quite reasonable when compared to buying parts individually.

So long.....