BarryReade

My Feedback: (1)

I have just purchased this engine and it doesn't match up with the pictures in the manual. The manual said the 65 came with the 9B Carb. The unit I have has the 8B Carb on it which requires a different back plate than the 9B Carb. The 9B is a bolt on Carb and the 8B is a slide in with a through bolt clamping system. My question is did this motor come like this from OS or has someone swapped some parts around and it is a hodge podge motor that someone put together. The bearing were corroded to the point that the engine would not turn over and is waiting for new bearings. Also some time in the past the engine ate some glow plug elements and a piece is stuck in the combustion chamber. Any suggestions for removal? It looks like it should run and as soon as I get it reassembled I plan on putting it on a test stand and see how it does. I have three exhaust extensions and plan on running a tuned pipe on it. If you have any information in the archives that can point me in the correct direction for the pipe I would appreciate it. I am going to put this in a propellor driven airplane and see if I can get decent performance out of it. All suggestions are appreciated. The only comments that aren't are the ones that say you can't do that it is for ducted fans only. I kno0w that the timing is cut for the DF and to run a prop I might need to play with the timinmg and the pipe to make power in a slightly lower rpm band.

Thanks for your time and efforts supporting the RC community.

Bax

My Feedback: (11)

Later engines had the carb retained with the drawbar. If a piece of metal is stuck to the head, then we'd do what it takes to get it out...if you can grab it with pliers, maybe it can be pulled out. If it can't be removed, you'll need an internet search to find a new cylinder head...or a new piston/liner assembly.

As far as propeller operation, we'd not know what prop would work OK. We do know that usually, a 12 x 8 was cut down to 10-1/2" diameter for breakin. You cut down the larger propeller because it had the thicker, stronger center hub. For normal operation, you'd want a tuned pipe intended for .61-.65 size engines that would turn in excess of 16,000-18,000 RPM. O.S. no longer has the parts or pipes you'd need for that engine.

BarryReade

My Feedback: (1)

Thanks Bax, you have provided more info than anyone else. I know I am going into uncharted territory so to speak. I went to a Model Engine Collectors Association Collecto this last weekend and picked up a pipe marketed by Jet Model Products. It is suppose to be for an OS .65-.91. I also picked up a .77 VR-DFand the instructions said take a 12X6 wood prop and cut down to 10" for the breakin and with no mention of RPM band. The .65 instructions I downloaded from OS just said take a wooden 12" prop, no specific pitch, and cut it down to 10" so the engine turning 16-18K rpm running rich for at least 20 min. Then slowly lean it out over several tanks of fuel. If I am not happy with the pipe I will contact one of the aftermarket tuned pipe manufactureers and get another one. I am also considering raising the sleeve in the in the case to retard the timing and will consider maching the head to keep the original clearance possibly

My next question is should I break this motor in using the tuned pipe or should I use the small 3" pipe that was is the box or just the open exhaust port?

Bax

My Feedback: (11)

You'll want to use at least the short stack. However, breaking in with the tuned pipe is OK, too, but just remember that it won't be properly tuned. Just keep it on the long side because tuned pipe systems that are too long for the RPM will trend rich.