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Topic: C8.3-300 Valve Adjustment (Read 431 times) previous topic - next topic

C8.3-300 Valve Adjustment

I suppose this could be in "What did you do today" or "It's always something", but I will put it in Foretravel Discussions.  Adjusted the valves today at 92k miles & 2300 hours; I also did it at 54K miles and 1400 hours.  Both times only a few needed adjusting and not much.  Engine manual says to do that at 24k miles, 1000 hours, or 1 year, but on the next page, it said first adjustment at 24k then every 48k interval.  I'm not sure what the other owners did, but I guess I am doing it too often according to mileage, about right for hours, and not enough for yearly, or maybe they mean just do it by mileage.  It's not an easy job; took about 5 hours, but part of the time was wasted trying to engage the timing pin.  It's located behind the compressor and I had to use a mirror and flashlight to locate it.  The only way to touch it is to remove the compressor.  I thought I could engage it using a small wood stick lever and a bungee cord while I rotated the engine with the barring gear.  Takes about 300 ratchet strokes for 2 rotations of crankshaft or 1 rotation of cam shaft.  Pin never engaged, maybe it was stuck or I needed a helper.  Wrote the firing order on a piece of paper and located intake and exhaust valves of a cylinder  that were both closed.  Rotated in both directions a little bit to make sure valves were closed and on the power stroke.  Checked and adjusted as necessary, then went to the next cylinder in the firing order and rotated engine until valves closed,  and repeated the process until all were done.  Checked them off on the paper as I proceeded.

Somewhat conflicting info from Cummins, but I am going to adhere to page 6-2 in the future.    I believe all the later electronic engines have hydraulic lifters; no adjustment needed.  Something else I have never done is remove the air compressor discharge line and check the carbon build up, that's next.

Re: C8.3-300 Valve Adjustment

Reply #1 –
Hmmmmmmm, When we had the injection pump pulled due to failure the mechanic reached behind the front ( rear on a MH ) cover plate on the curb side and while assistant BARRED over engine engaged pin with no problem, took
 less than a rotation to catch it. My memory is fuzzy but as I recall the pin had a kind of knob on it that was easily pushed in to engage.
Gary B
 

Re: C8.3-300 Valve Adjustment

Reply #2 –
Quote from: Gary Bouland –
Hmmmmmmm, When we had the injection pump pulled due to failure the mechanic reached behind the front ( rear on a MH ) cover plate on the curb side and while assistant BARRED over engine engaged pin with no problem, took
 less than a rotation to catch it. My memory is fuzzy but as I recall the pin had a kind of knob on it that was easily pushed in to engage.
Gary B
Yes, removing the injector pump would also allow access.  It does have a knob that is slightly less than 3/8" diameter as the 3/8" flat bottom hole in the end of my wood lever fit over it.  It's a rather useless device if you have to remove the injector pump or compressor to use it.  Maybe a good thing my lever did not work, as it may have been even more difficult to disengage.