Cummins ISM Tune Up

[Brian Diehl]

I've read several times in the past of people doing tune ups to the DD engines that don't exactly match what the book recommends.  The tune up is done based upon experience and usually yields superior results.  I'm wondering if anyone can give me some pointers on setting the overhead on my ISM.  My ISM is a year 2000 motor without EGR and does have Jake brakes.  Any input or guidance would be appreciated.

One little issue I have is a lack of timing marks.  The accessory pulley did not have the timing marks on it the manual says it should have had.  My Cummins shop told me that was not unusual.  So, I have to find the proper way to "recreate" the timing marks.  Are there any "sure fire" ways to accomplish this?

I've read "da' book" and it sounds pretty easy to set the valves, injector, and Jake brake clearances.  I hope this is close to reality.

[TomC]

Unlike the Detroit 2 strokers, the Cummins ISM is a simple engine.  Adjusting the proper clearances to the valves, injectors and Jake brakes is about all that is required.  As compared to the 2 strokers that have different cam advances or retardings, injector height, rake adjustment, various mechanical injectors that can be used, etc.  The Cummins ISM does have a maximum RV output of 500hp and 1550lb/ft torque, but involves a specific engine build with the proper pistons, injectors and turbo.  You should have Cummins run your engine serial number to determine the maximum horsepower available from that engine.  If you can get at least 350hp and 1300lb/ft torque, that should be sufficient.  Good Luck, TomC

[Brian Diehl]

Thanks Tom.  The engine is currently setup at 400hp and 1450 lb/ft of torque.  I didn't think there was any modifications to the factory specs necessary, but thought I'd ask in case experience had shown some minor tweaks to make a difference in the performance of the unit.