6V-71 powered, 850cfm air compressor. Had this a long while and setting up my blast line again so fired her off after about a six year "nap".

https://www.youtube.com/watch?v=7zA6UPhwfMw" rel="nofollow - https://www.youtube.com/watch?v=7zA6UPhwfMw

Client years ago had a Leroi Compressor 6L71, Two Valve head OLD early fifties late forties engine.  Had three Lobe blower, squalled like no other ever heard thru the Oil Bath air cleaner.

1983 Ingersoll-Rand P-850B-W-GM is the year and model. Very good compressor still, and going to make use of it again.

I purchased this several years ago for needed projects one of which was clearing irrigation lines for repairs, or winterizing and it does a really good job of that. 

I need to pull the heads as have an oil leak on the left, and seepage leak from the right at the rubber perimeter seal(s). May touch up the valves and guides at the same time as the engine really is a solid performer.

I like Detroit Diesel two strokers too. Still have a 6V-92TA, 12V-71T, 8V-71, 3-53, and this 6V-71 all which run very well.  

I always liked the sound of those----for a short time!!  Used to have to work close to them sometimes back in the day when I was running a portable welding truck and would get called out to a drill site to do repairs etc when the rig was tripping pipe.  Ears would be ringing fore a day or so after.

They are a very good engine for converting fuel into noise!! LOL

Few more of the compressor engine and air end:

Compressor has no air cooler so I run the discharge air through this external cooler to condense and drain off the moisture:

Cooler has an air motor that is lubricated with automatic transmission fluid. I need to plumb a drain hose and catch can prior to the exhaust muffler from the motor to keep from saturating the core as you see in the photo. I could then also reuse the oil if captured clean. 

Talked to the local community college diesel trades instructor about rebuilding this engine for a class project. I was told the administration would not allow it as an "out of production" engine, and they didn't know anything about them as not in their curriculum?

I look at it as another prime example of the future we're headed into. Can't plug a laptop into it; so lost. 

Ordered a complete overhaul gasket set for the engine this morning. I'll knock enough of the enclosure off the unit to use my boom truck to lift it out leaving the compressor section in place.

Called I-R, (Now Doosan) with the serial number(s) of both the unit, and air end. They provided an electronic manual of the machine and informed the compressor is "as built". Also a wiring diagram, along with an air plumbing schematic so pretty well set. No blue smoke from the engine at all, but it does belch black when the throttle comes up. Customary of an old Detroit, it likes a "sniff" of ether to start cold. Not addicted by any means, but it sure helps. The "measured shot" dispenser works well so nothing wasted and the cylinder is still available readily, (albeit $$$) compared to days gone by.

Mcmaster has the 1" thick mylar faced sound attenuator available so while broken open I'll probably renew a lot of this as some is missing. There is noticeable difference in sound transmission through the doors where this is missing as opposed to the sidewalls where it is still present.

I-R also informed me the compressor is a 750cfm unit and not 850cfm as built by the serial number. Same compressor but a different set of rotor drive gears is the difference along with a 25psi lessened rating to the larger set. Regardless, I blast at 90psi-100psi and it's still a lot more air than consumed/needed so good by me. Once I get it sealed back up it will return to service.