Jake brake adjustment

[joed2323]

Ok, ive adjusted jakes before on series 60s and its cake walk, its simple.

Please give me the run down on why the adjustment of the Jake brake is odd to me on these cm2250s/871s/cm2350s?

Ive watched rawze video on the injector swap, and he ran thru the overhead, (the overhead makes sense to me) but the jakes on how you have a toleance of +/- such a min/max is odd, especially coming from a series 60 were you adjust the Jake brake and your done...

With these cummins motors if jakes are for example over spec,you have to loosen the rocker shaft bolts and "push or rotate the shaft towards where it needs to be then retighten down the rocker shaft stud bolts and recheck the tolerances for the jakes. .

Ive adjusted valves on two motors now and, yes I had the rocker shafts off and installed them. Yes I understand either the front rocker shaft or rear rocker shafts have to be installed and tightend down when the rocker shaft is down not bolted down when the valves are pushing it up... I ran thru these motors and checked the given min/max tolerances and thankfully the were perfect. But it just didnt make total sense. If it was off for example I would think just to loosen the adjuster nut on the given jake that was out of adjustment and adjust it. Walla done...

I just dont necessarily understand the engine brake adjustment procedure and why on these motors.

I know you guys are gonna use caution towards me and be shocked that I ran two overheads but just didnt grasp why the engine brake has "any" given tolerance to be within spec...

Well I dont like that. I want my engine brake to be spot on and "great" engine brake.

Their is a adjustment screw for the Jakes... Do I have the procedure backwards, and I only need to adjust the screw/nut adjuster in the "detent position" which to me makes sense to me! If its off you adjust this. Not loosen up the rocker shaft bolts and adjust accordingly???

Thanks guys for being patient.

I really just want to understand this jake brake adjustment procedure, and what throws me off is with it being within spec from a min to a max spec, not just a specifed spec of say 7mm

I even used a dial indicator like rawze did on the jakes, they were all within spec but I just still didnt understand why these jakes are allowed such a wide tolerance that is sufficient to work, not just a .027" for example. Woops its off, let me loosen the Jake brake nut and turn it towards the correct direction to make it exactly .027"
Again the # I stated is wrong, just a # used in this example