Air Compressor Cummins Big Cam NTC 855

I’m in Pennsylvania now or I would take a pic of my Factory Cummins shop manual so you could read it.... with a twin cylinder timing is not needed.

Here’s a couple pics from one of my Big Cams.

 

Some are indeed blue......

 

Pictures, we like pictures...... and coffee

 

I was changing an air compressor on a Cummins one day and fellow veteran tech was bullcrapping with me. I was barring motor over and he asked what I was doing. Told him time balancing it to the engine. Really, he said, I never knew that and he said he probably changed two dozen compressors on Cummins. I know Cat with single jug compressors have no instructions to time them.

 

If you were lucky, all the injectors would work at all RPM's. If you didn't time it, most people would never know from the vibration if it was the "normal" vibration or not. I was screamed at one time for not doing it, so i always did after that.

 

Thanks I did not know that about cats. I still did the side of the road deal. TDC on acc drive or a timing pin in flywheel. Did not have windex or 409 so spit on the thumb and air outlet fitting. Turn the drive gear in the normal direction of rotation. Hold your thumb loosely and the bubbles will quit at TDC. Turn it back and forth 2 or 3 times to double check that. Then turn it back one tooth allowing for the angle of the gears. Bolt it up. The Bendix twins can be done the same but I do not thank their is any advantage to that.
Seemed to work better for the old man chewing tobacco.
Often times increasing the idle RPM slightly gets rid of a whole of the gear train noise.

 

Just another reason to continue one of my bad habits and spit on the shop floor!