Troubleshoot engine noise - Major or Minor problem?

[RBridenbaugh]

After a week of boondocking with my truck camper in the Seqouia National Forest, I was returning on a dirt road going down a pitch of less than 15 degrees in 4Lo with my exhaust brake on, when after going over a transition, the engine started to clatter very loudly.



I pulled over and checked the engine and drive train. Oil was right at the add mark. Added one quart and carefully worked my way out to civilization. Noise decreased over ~ 15 minutes.



Was it just like air in a lifter and taking a while to work out or is something major going on that I should fix before it gets much worse and I get stranded on the next outing?



Suggestions or Opinions?

 

[rscurtis]

You can be sure that it wasn't air in a lifter, as these engines have mechanical lifters, hence the need for periodic adjustment.

 

[HBarlow]

I have no offroading experience so don't KNOW but would have to guess the combination of a steep operating angle (aboard a submarine roll is side to side angle and pitch it up or down at the bow, don't know about angles in offroading) and low crankcase oil level probably caused a period of oil starvation where the oil pump was sucking air.

If you were operating at low rpm and light load you probably didn't cause severe damage since the mighty Cummins is pretty rugged.

 

[RBridenbaugh]

Noticed the truck started using more oil. About a quart per 400 miles. Also noticed more and more blow by (enough to lift the oil fill cap when unscrewed).



IR spot meter showed cylinder #1 running 20 degrees colder. Best scenario would have been a valve dropping a seat, resulting in a bent valve and a destroyed guide as the source of the blowby and oil consumption.



Erik at Left Coast Diesel pulled the head. Good news was that the valves looked OK, unfortunately Cylinder 1 looked like this:



#ad




0. 040" to 0. 060" scoring on the cylinder wall. So much for the good scenario. No pieces found yet of what did this to a stock engine with 145,000 miles. Pistons coming out tomorrow. Expect to find a ring in pieces or missing. Other cylinders looked really nice and could still see the crosshatched hone marks.

 

[cerberusiam]

Eek!!



Injector tip plugged or cracked and spraying out of the bowl?

 

[retirednak]

You can be sure that it wasn't air in a lifter, as these engines have mechanical lifters, hence the need for periodic adjustment.

Sorry about jump your thread.



Do you mean periodic valve adjustments? Don't know what periodic lifter adjustment is.

 

[cerberusiam]

Do you mean periodic valve adjustments? Don't know what periodic lifter adjustment is.

Its the same thing, adjusting the valve lash adjusts the tappet clearances.