Diesel chainsaw

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Was the comet a true diesel with compression ignition, or was it just burning diesel fuel using a hot bulb or glow plug or spark ignition?
Although I've never actually played with one, I've always been under the impression they were a Hot bulb engine, or Semi Diesel. Someone more knowledgeable may be along to correct me shortly!
 
i had a diesel aero engine like this, tapered bore, ringless piston, and sliding liner to increase the compression after starting it, loved the smell of the castor oil :)


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I was flying Remote Control back in the early 80's. Got into the study of AC design and tested them with RC...Boy that was fun..10 or more years.. Finally met a guy with a full size bi-plane and begin to fly with him..Then passed my test for a single engine about 85..LOVE flying..LOVE airplanes. Went from that to Sail boats.. LOVE Sailing..Your post brought a smile on my face. My little girl born in 79 loved going with daddy..She's in her 40's now and gave me 5 grandchildren..What great memories..I'll never forget landing in cross winds by slightly lowering the wind wing with ailerons while holding opposite rudder and making a smooth landing..I perfected that with RC planes.. I was amazed at how many did not know that trick..Also..Elevator acts like Rudder when plane is in a Spin nose down..Ha. Ha..I think EVERY pilot should take classes on RC before getting a license..I taught a 30 hour course. They learned how to take off land under power and also dead stick.. One of my students became a professional Airline pilot.. Thanks for the reminder..
 
Was the comet a true diesel with compression ignition, or was it just burning diesel fuel using a hot bulb or glow plug or spark ignition?
Excellent question. These are not true diesel engines that use compression for ignition. They are indeed hot bulb engines. If I recall correctly, compression ratio is only about 8:1.

I've had several XA and Comet diesels, but sold my last one a year or so ago.

More details here - https://www.arboristsite.com/threads/diesel-chainsaws-and-the-women-who-love-them.318719/
 
Excellent question. These are not true diesel engines that use compression for ignition. They are indeed hot bulb engines. If I recall correctly, compression ratio is only about 8:1.

I've had several XA and Comet diesels, but sold my last one a year or so ago.

More details here - https://www.arboristsite.com/threads/diesel-chainsaws-and-the-women-who-love-them.318719/
This might seem like a stupid thing to say,,,,BUT my guess would be the Diesel is a lube too so in a 2 cycle engine it might be great. No mixing, just buy add and cut. I've never seen a 2 cycle Diesel. Have no clue. I'd guess they might be more like a Small Hobby Engine. The fuel for my RC engines was expensive. It had Nitro mixed in. A small one pumped out 1 HP and had plenty of power. Loud as elll. Power band seemed to be WOT but that's where my Chainsaw runs.
 
Probably too dirty to attempt today. If they did run clean for modern standards, I wonder if they would be any good for small wood? They wouldn't be snappy, quick revving like gas saws I wouldn't think. I bet a 90-120CC diesel saw would be fun though. You could probably lean right into it and it would pull a massively long bar, so long as the oiler could keep up. This all speculation of course of how a diesel saw would run. Probably really doggy and slow to rev for normal size firewood bucking and such, but then again, if they could fuel inject it, like their starting to do, but I don't think the EPA would be too happy with diesel saws these days regardless, I don't think many of us would be happy with their performance either unless pulling a 4 foot bar or something crazy.
 
Just to give them more power. Sometimes they had both
The deteoits needed the blower to run. They were a uniflow design, not loop design like a saw. The crank case was separate from the cylinders, and held sump oil. Pretty common to have to replace the little drive shaft for the blower in the trucks when you got a cranks but doesn't start complaint. Used to keep a few in the service truck just for that reason.
 
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