ORIGINAL: hobbsy
As to those Enya glow plugs, there are none better in an Enya. My 14 year old .46MKII still has the original in it. And that is after three years operation using Fox 15% nitro fuel with 20% castor, several years on Byrons and finally WildCat Premium. Here it is waiting to be mounted on a US Aircore Colt 40. It will be the third USAC plane it has been on.
Dr. B, is your .53 the TN version. Also, were your timing gears rusty, I took mine down to inspect things about a year ago and the were really rusty. I now remove one of the carb bracket mounting bolts and inject Corrosion X between uses. The rust is almost gone as Corrosion X removes it over time as long as it's just surface rust.
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When I first got my Enya 80-4C, around fifteen years ago, I had very little flying experience with four-stroke engines. Lots of bench time, but not much flying time. My 80 did not come with a muffler, just a straight pipe. It wasn't really all that loud running a 13x6 prop, but I was worried what the other club members would think about it, so I did several polls at the field, asking whether it was too loud or not. Everyone said it was just perfect as it was and not to buy the later released muffler for it. I didn't.
One thing about running with the straight pipe was that you could hear each and every miss, clear as a bell. With the Enya #3 and Tower four-stroke plugs, it did miss, but it never quit and it ran quite well. But that miss was getting to me. No matter how I tuned the engine, even though it was running perfectly, I couldn't get rid of the occasional miss. I even nicknamed it "Five O'clock Charlie", from the MASH episode that featured the lone commie biplane bomber that flew by at five every afternoon, missing and sputtering all the while. My Enya didn't miss like that, just occasionally. Someone loaned me an OS Type-F plug to try. I checked for interference and discovered that, indeed, the piston was just barely touching the tip of the glow plug. No problem, I installed two washers. The miss was gone!
Now, was it the difference in glow plugs? Or the ever so slightly reduced compression when using two washers? I'll never know, because I "assumed" it was the Type F glow plug. I wish I had put two washers under the Enya #3 glow plug to find out. Enya four-strokes have quite a bit of compression, when healthy.
That was an exceptional Enya 80 4-C, or so I have been told. As I brag - er - mention from time to time, that engine would provide enough power to let my Goldberg Cub climb in knife-edge flight. Honest Injun. Since they are fairly rare engines, I've never seen another one run, so I don't know if I had one of those one of a kind freak engines that occur every once in a while or not. I'm about to find out. I just bought another Enya 80-4C from one of our RCU brethren. All I have to do now is pay for it! The check is going out tomorrow. Honest!