Isx cm2250 engine brake choppy
02-25-2018, (Subject: Isx cm2250 engine brake choppy ) 
Post: #5
RE: Isx cm2250 engine brake choppy
(02-24-2018 )aaronb Wrote:  The truck has 699,000 miles. The engine was rebuilt at 482,000. I'm not sure the reason for the rebuild. It still has the mandate. No bypass filter installed yet. I just bought the truck a couple months ago. I know the previous owner was running 20,000 mile oil changes. The overhead was just ran about 20,000 miles ago. I was driving the truck and bought from my boss. I'm planning on running the oil changes at 12,000 to 15,000 miles and adding a bypass filter. I'll try solenoid first and go from there. We're having freezing rain today and I don't have a shop to work in. Might be next weekend before I get a chance to check it out. Thanks.

I would expect the 20k mile oil changes in a mandated engine to be the cause...
The effects could be many, but I'd almost expect that you have soot saturated oil partially blocking things in the Jake oil circuit...even if this isn't the current problem, it will become one.

I would highly recommend at least two 5k mile quick oil changes to try cleaning out some of the sludge that undoubtedly has built up inside your engine.

If/when you pop your rocker cover to inspect/find your problem, even if it's something as simple as a broken wiring harness...I highly recommend that you pull both valve rocker shafts, disassemble them, use copious amount of brake clean, and clean out all of the oil galleries in the shafts and the rocker arm! There is probably a good amount of gunk built up in there.
With that many miles on the engine, unless the rocker shafts and some or all of the rockers were changed when rebuilt (doubtful), I'm fairly certain that your rocker shaft detent holes will be oblonged and the rocker shafts changed. If/when you change these, also change the check valves and the springs in the rocker shafts. The check valves seat into the detent holes, and if one is worn, so is the other. The springs will be weak after that many miles.
I used to have a thread on the forum describing this procedure, and pictures showing worn vs new parts and new vs old springs. Unfortunately it was one of the threads lost in the last crash. I believe I still have a set of worn parts at the shop that I can post pics of when I get back later in the week if I have time...

When the oil is cooler it is thicker and can overcome the leakage from worn detents and check valves. When it get hotter and thinner too much leaks out the worn surfaces causing erratic response. This is where shimming an oil pump can mask the issue as I previously stated.

With a mandated engine with NO bypass filter, you should be doing 10k oil changes and don't even think about more than 12k when you get your bypass filter put on.


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Messages In This Thread
RE: Isx cm2250 engine brake choppy - Hammerhead - 02-25-2018



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