RE: Why (an Enya 11 CX D) Diesel?
Hi all I'm new to this forum. Can add my experience with the Enya 11CX in diesel form. We used them in Mini Goodyear - converted to diesel using a head from Nelson 15D machined down to suit Enya's smaller bore. Then drill & tap the crankcase to accept six mounting screws, make some shims to adjust chamber volume & there it is. They were soundly beaten when the OS 10 pylon special came out, but for a while, it was good fun. I did eventually get around to testing my engine (for the record). It has a Cox carby fitted - drilled to 4.0mm bore. Peak power was 0.48BHP at around 21,000 RPM, which is quite good for a diesel of that size, especially remembering that the design is around 30 years old. We did find that in diesel form & pushed for max performance that the 3.5mm wrist pin would break. Easy enough to ream out the piston bosses & fit a 4mm pin. Enya machine the circlip grooves deeper than they should really be, so no problem with the larger hole & circlip fit. In terms of exhaust port ( and intake or transfer port) timing, there's no need to change anything. Yes, used them in glow format too in C/L Speed models & in their day, they were tops. Enya use the same alloy for both piston & cylinder in the AAC setup. Around 16% silicon according to my spectrographic analysis back in the early 1980's. That's OK in glow form, as you can get by with a slack fit when cold & still start it fine & then the piston expands up to a good working fit at running temperature. Not so as a diesel if you want first-flick restarts. We'd selectively fit pistons in cylinders to arrive at a good diesel fit, but they lost their edge quite quickly. Thereafter performance was fine, but restarts were a bit theatrical. Douse the cylinder with fuel, fill tank & then get it started. A sensible cylinder bore taper & selecting a piston with lower expansion coefficient lower than the cylinder would have fixed that. Also worth mentioning is that these engines seem to have relatively poor suction. Our attempts at the time in using them as diesels on suction in combat models were not satisfactory. The factory diesels have a fairly primitive diesel conversion setup that uses a cast iron insert and contra-piston. I doubt that one of these would come up to the performance figure that we obtained, but is probably not intended to do that and at more moderate speeds, it would be all smiles from the user. Maris Dislers
Posted on: 4/1/2011 1:27 AM by Author "MArisD" in the forum "Everything Diesel"
http://www.rcuniverse.com/forum/fb.asp?m=10435933