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Need help adjust cummins small cam overhead. Dial indicator method for injectors.
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By itali83 - Tuesday, April 02, 2013 1:48 PM
Hey guys, long story short (kinda). Pulled injectors on my dad's '75 small cam CPL 160 and had them balanced and flowed out 25% more. But same injectors we took out I just put back in after being checked over. I have the cummins dial indicator, cummins book and cummins overhead cheat sheet, I wheel thing you turn and it tells you which valves/injectors to adjust at which timing mark. Both book and cheat sheet match up.

I'm under the assumption that the injectors are adjusted on the outerbase of the cam and the spec is .169" of travel. Now, this means that when on the outerbase circle of cam, you should have .169" travel when you manually bottom out injector and the spring brings it back against the cam lobe right?

I went through the adjustment the first time and found that with the injectors on the outer base circle, my exhaust valves ended up really loose and the compression release worked very easily, (I obviously adjusted the valves while they were on a part of the cam lobe) Thought I was just on wrong cylinder for the timing mark, but when I tried to adjust the other cylinder and injector, I found the valves were good but injector seemed to be on inner base circle and I didn't dare adjust them for fear of bottoming them out and bending push tubes or messing injectors up.

I figured that maybe someone had the accessory drive off and never timed it again. FOR THE RECORD, THE CRANK TO CAM TIMING IS CORRECTLY TIMED!!!!

So I started from scratch, put the dial indicator on one injector rolled the engine over until it was at max lift, and adjusted for my .169" and did corresponding valves and everything seemed good. Started truck and ran like dog do do. Massive ammounts of black smoke at idle, popping out exhaust, when revved and coming back down it sounded like the jakes were on but the truck has no jakes. When shutting it off, it would "diesel", run on like it was running out of fuel, not shut off normal.

I was convinced that the acc drive was out of time and thats why I was having a hard time, but tonight I took everything apart to find the marks are lined up properly, 2 dimples on acc drive lined up with 2 dashes on cam gear.

SO,,, my question is, what am I doing wrong? Do the injectors get adjusted at max lift or at another set point on the cam? Why don't you adjust the valves on 1 or 6 when timing marks are on VS1-6? My book says

VS1-6 = Injector 3 or 4 and Valves 5 or 2

VS2-5 = Injector 6 or 1 and Valves 3 or 4

VS3-4 = Injector 2 or 5 and Valves 6 or 1

This makes no sence to me since VS stands for valve set.

I just need to be 100% sure I'm setting them right before I chew out the injector guy for messing up my injectors. Sorry for the long post but I wanted to put all the information out there, I'm no green horn to working on motors, just never set old school cummins before, done more N-14's and M-11's than I care to think about. Thanks in advance!!
By 4bangor - Tuesday, April 02, 2013 3:18 PM
Old school advice;just use the old school torque wrench method, it works every time. Heres what an old timer passed on to me and it eliminates the guess work on acc. drive timing, Put a wrench on #5 inj., bar eng over until the wrench just starts down. Look at timing marks and i bet ur right on the marks if timed right. When that occurs #1 cyl. is ready to set, inj, first, then adj. valves on same cyl. then put wrench on #3 and bar over till it moves and #5 is ready.then proceed till all 6 are done in firing order sequence. from recall the torque is 144. INCH pounds. All ur really doing is setting the inj. to what amounts to is about zero lash. two bits,,
By nwvintageagparts - Wednesday, April 03, 2013 5:00 PM
Im doing the same thing on the SC350 cpl 160 in my 63 KW right now. The info I have out of a Cummins Service manual says to adjust the injector on the same cylinder you are adjusting the valves on. So when #1 is on TDC, adjust the injector, then the valves, then #5, #3, #6,#2, #4.

Specs are

Cast Rocker housings

Cold 48 IN LBS Valves Intake .016 EX .029

Warm 72 IN lbs Intake .014 EX .027

Alum Rocker Housings

Cold and Warm 72 IN Lbs Valves Intake .014 EX .027
By 1969 KW 924 - Sunday, April 21, 2019 1:20 AM
Thanks jim
By jimfols - Sunday, April 21, 2019 4:15 AM
1969 KW 924 (4/21/2019)
As I recall this sounds correct, I hope jimfols chimes in on this as he was able to set the crack of Dawn! my old Boss set um looser tho. Grubby

Thanks for thinking of me Grubby but that thread is from 2013.
By 1969 KW 924 - Sunday, April 21, 2019 3:23 PM
Jim do you remember me?
By jimfols - Sunday, April 21, 2019 3:55 PM
if you know all about trucks and pups, then yes I remember you.
By 1969 KW 924 - Wednesday, April 24, 2019 8:59 AM
Yup that would be me Thanks FOR THE MEMORY search all the time for any trace of my " Pal" Manuel B