Showing results for 
Search instead for 
Did you mean: 

M11 Cummins Overhead Set (OBC)

Doing an overhead set on a M11 cummins STC on a 9350 Steiger and was told the best method or newest way is to use the outer base circle(obc) method.  My only concern is that you are bottom out the injectors at 125 in/lbs and am not sure how this doesn't cause problems with wear on the bottom?  The old way in the book that I have you hold the tappet up and tighted with a torque screw driver to 6 in/lbs.   So I set one to the book and when I got to the cylinder I torqued it according to the obc method and it turned in about 1.5 turns.  Not sure why there is such a large distance between the old setting the new?  So what I was wondering it if you could torque them down and back them off 120 degrees two flats on the set nut to be safe that they don't overbottom and not have problems?  I had the injectors rebuilt and the place that rebuilt said the obc is the way to do it and I also asked a local mechanic and he said the same still makes me nervous.  I have bought a good torque wrench and am not trying to cut corners. Any help or experience is appreciated.  

0 Kudos
1 Reply
Frequent Contributor

Re: M11 Cummins Overhead Set (OBC)

Caution!  an STC engine is different in that it has oil lines to the injectors. A special tool was required to compress the oil from the tappet and hols it up during the adjustment procedure....install tool on cylinder you are adjusting, compress oil and hold tappet, make adjustment, remove tool and move to next injector.  Its been a long time since I actually did one, but I know they were different.  When you think of the catastrophic damage that can be done by wrong adjustments, it may be a good investment to have a qualified tech pay you a visit.  I am a very accomplished mechanic and I have tackled some crazy things....but I know my limits.  Best regards.

0 Kudos