I'm posting this because I get asked this question many times through the years. {How does the crank and rod assemble on a Cummins compressor with no bottom inspection cover?}. Pretty simple really-it has a pass through crank shaft. The one below I'm rebuilding for a friend is the common Holset SS296 found on small and big cam Cummins and also used in other model numbers on various Cummins engines. 13.2 cfm 3.625 bore with a 2.00 stroke. The parts are available for a rebuild cost with shipping $185.00. The rod is aluminum with no insert bearing. To remove crank-rotate crank so rod journal is 90* to bore, remove front bearing/mounting support and carefully slide crank out fishing con rod through rear crank journal. Very simple. Coolant only flows through head cooling top of piston and air. One problem these always had was carbon deposits plugging the ports in the head. The unloader is all located under top cover and in cylinder head, several parts but simple. Plus There is a timing procedure-rotate engine till A-1-6 valve set mark is lined to pointer, there is a scribe mark on the end of the compressor crank shaft set that between 9 and 10 o'clock. Although in Cummins N14 {2003} manual It says it makes no difference on NT series engines-except BCIII's and NT88's -go figure. I time them all. Average reman price is $375 with a $300 core.
We used to put a restrictor fitting in the outlet of any new or re-ringed compressor and let it run for 1/2 hour blowing into the air to help seat the rings. We never had too many oil pumping complaints after using this procedure
Regarding timing, I was once in a hurry and "just slapped it in". That cost me time, guy brought off the ready line and straight to the shop. Knockin hard. I brought back in, took it down and timed it like i should have in the first place. No more knocky-knock. That cost me some of my gains that week. Never again.
So I've got a big cam in my old ford l9000. It has what I've always thought of as "the worlds noisiest compressor". I guess that it may be out of time? Its always pumped air just fine, its just super loud.
Most of the Cummins six cylinder 855c.i. engines I worked on were the old small cam version. Every once in a while you would be trying to do an injector replacement or valve setting and come to the realization that some SOB had replaced a complete air compressor and did not think it needed to be timed!
I’ve got the wrench for that. With the 5/8 outboard side ground & polished to get that much needed extra 1/96 of a turn. And yes, I keep it my utensil drawer for air compressor emergencies.
The accessory drives were often miss diagnosed for noise when actually it was a out if time compressor on the 855. Really for what the Holset series SS296 and others similar it's a fairly reliable compressor.
JY has my old Cummins Tools, I was done with those. At one time was cheaper to buy a Cummins Reman than attempt a reman of a customers unit, times have changed.
On big cams if the accessory drive for compressor was installed out of time. Find TDC #1 by watching valves on #6 valves should be just at one opening and one closing. Then re-measure the marks on accessory drive pulley for A, B & C so injector valve settings come out right.
I actually like those compressors. Had a parts idiot tell a customer that there's no major unloader rebuild kit available and that they'd have to get en entire compressor for $1,100+ lol last week.