Smoking Cummins 855

One or two cylinders not going advanced will generate lots of smoke. If all 6 cylinders are in, the engine overhead noise will be smooth & uniform. I've had some engines that needed to be driven to fully purge the overhead. That engine should have a viscosity sensor to boost the cold oil pressure to around 80 or so psi. If you can install a t fitting into the stc supply line after the valve you can measure the pressure to the overhead. It should be close to engine oil pressure. You need to know that number to determine if the stc system is supplying enough oil.

 

This may have nothing to do with this engine. But I bought an old Fordson Major 5000 Tractor. This was back in the late 80's. Old tractor ran perfect, other then a little hard to start And smoked white smoke. Raw fuel smell was so bad. it was hard to stay on that tractor.
I bought it for junk price. Used it for 1.5 years, and could not find anyone that had an ideal how to work on these old tractors.
Went to replace the pie shaped injector pump pieces. And got that deer in the headlight ideal. Was this pump 180 degrees out of time?
I marked it where I could go back to where it was if this ideal Shot the bed Fred. That engine started like new, no smoke at all. Ran perfect for years after that.

So just make sure everything is timed right. I know a guy that used to haul hot mix with us. He bought a new truck. It had the 444 in it. Truck was a hotrod grossing 74,000 lbs on a Tri Axle. That truck was a runner. But from day one smoked like your talking about. None of us wanted to be around his nice new truck. When its 105 degrees, you have tons of 350 Degree mix on the back of that truck. The truck is running AC wide open. Even the Paving crew screamed about how bad the fuel smell was while the guy unloaded.
I think he had Cummins about to give up on it also. Then he found an old Smart ### driver in our bunch. That old man had told him at the first. The truck was not timed right.
Turned out the truck was not timed right. They timed the pump to the Accessory drive. And cleared it up, where the truck could be used.

 

Oil pump sucking in air from pickup tube and causing aerated oil is known to cause erratic operation of STC injectors.

 

There is a quad ring, square O-ring, between the tube and fitting on one end with long bolts. They can suck air there. Often over looked.

 

On the right side of the accessory drive pulley is a plug. Requires a 5/16 square drive for removal. The timing marks should be able to be checked there. The PT fuel pump is not timed. The air compressor should be on TDC the same time as #1 how ever it will work anywhere. If you cannot see the timing marks remove #1 injector and put it at TDC. There is a mark on the accessory drive pulley for TDC and sould be aligned with the tab on the front cover. Then adjust the injectors by the book.
I have noticed an odd spot on some Cummins cams but I never turned one around to see if there was a higher spot than the set point. I do know if you set the injector torque less than specifications all you gain is smoke. Just my two cents.

 

Can you plumb a gauge into the braided line that goes from the STC valve to the oil manifold that feeds oil to the injectors and see what the pressure is it idle when warm. As a previous post said it should be close to pump pressure. If there is a leak in the plumbing inside the rocker housings its going to smoke. What is the oil pressure at idle when the engine is warm?
It is very important that the accessory drive is properly timed to the cam gear to get the injectors properly set. The 1210 CPL engines were the worst smokers. They were timed at .138" if I remember correctly. I used to advance them to .132" and found it made a big difference.