Adjusting the valves on a Cummins 6BTA

[Russell]

Has anyone adjusted the valves on their Cummins 6BTA and can tell me how hard it is to do? There is a special tool to rotate the engine to top dead center and I only want to buy it if I am pretty sure I can do the job myself. There is supposed to be a pin to push in a hole in the flywheel that locates TDC but I cannot find it on my engine. Anyone know where it is?
Thanks for any advice.

[Merry Kate]

Russ -

Piece of cake as far as valve adjustments go, especially with the top access of the motorbox 28's. The tool is a simple splined socket with a 1/2" drive that bars the flywheel around. I bought one at a Cummins dealer that came in a little case with wrenches & tools for like $30.

The TDC pin is on the back of the bell housing (engine side) if I remember, as is the insert for the barring socket. Or you can locate TDC by the rocker arm pattern. If you use the pin, be careful to withdraw it to keep from breaking it off when you start up.

The Cummins O&M manual illustrates the adjustment procedure very well if you have it. If not, just a basic 6-cyl valve adjustment. You can always poke around on boatdiesel too.

The Cummins 6B is as dirt simple a motor as you'll ever find to work on. Don't be surprised if you find all the valves in tolerance - they don't seem to go out very easily. Good luck.

Ed

[Russell]

Ed, Thanks for the info. I have the manual but the drawing of the timing pin is such a close up that it is not possible to tell where it is located on the engine. Is it on the side with the air filter? The manual says it goes in the camshaft gear. Do I rotate it clockwise or counterclockwise with the barring tool? The manual describes a way to adjust the valves without using the timing pin by observing when an intake valve closes but it is much easier if I can find TDC. The valves were adjusted just about 1000 hours ago so it is time to do it again.

[Merry Kate]

Russ -

I can't remember for the life of me which side the timing pin is. Next time I'm down at the boat I'll check and get back to you.

Ed

[Merry Kate]

Russ -

I checked this afternoon: The TDC locating pin is indeed on the timing case (under the injection pump), facing towards the block. It's just to inboard and a few inches from the raw water pump. I was thinking of the insert for the barring socket, which is on the flywheel side of the engine, facing towards the block. (It engages the ring gear, just like the starter.)

Ed

PS: rotation on a 6B is CCW looking at the flywheel from the bell housing (i.e. standing forward of the motor box looking aft).

[Russell]

Ed: Thanks for your help and encouragement. I found the timing pin hidden behind the raw water pump and the opening in the bell housing for the barring tool. I checked and adjusted all but cylinder 2 and 3 which I could not expose because someone rounded a nut on the air intake crossover plate. As you said, half were still in adjustment and the others were just slightly loose. I am not sure it is worth all the trouble it will take to remove that rounded nut to get to the other rocker arms.