Cox Diesel engine with no teflon disk or o rings!

Nice job. Looks really well made. Have you used a heavier duty crankshaft? I'd be worried about over-stressing the crank pin and ball-joint.
Not sure what Valentine engines use, but I'd never seen discs or o-rings used in diesel engines prior to getting involved in the Cox scene. I grew up with diesels as a kid and they all only ever used a contra-piston close fit in a sleeve.

Hope you have good success with it.

Rod.

O rings have been in use for 65 years ( O.K. and McCoy ) on contra pistons . I really like that slave cylinder set up . New to me and I've made a few diesel heads in my time . And yes a Diesel crank or heavy duty crank is a good idea if you plan a long life for your engine .
Mike 1484

Mike1484 wrote:O rings have been in use for 65 years ( O.K. and McCoy ) on contra pistons . I really like that slave cylinder set up . New to me and I've made a few diesel heads in my time . And yes a Diesel crank or heavy duty crank is a good idea if you plan a long life for your engine .
                           Mike 1484

It only seems to be U.S. engines that use an o-ring. Not sure why that is or what the perceived advantage might be. The only thing I can think is that it may cut production cost by not having the extremely fine tolerances of the contra-piston fit used in European diesels. The o-ring also gives the engine another potential point of failure.

Yes, we never understood the teflon and o-ring stuff on this side of the pond...  

One can also make a proper counter piston inside the head, without having to modify any cylinders. This was sold as an after market product here in the early 80-ties, the smaller counter piston diameter gave an easier tuning: