I found this old diesel power unit down the road and I would like to hook it up to my belsaw, does anyone use the twisted flat belt anymore? or would a jackshaft be the best? A neighbor put his power unit over his belsaw but this one is too heavy for me to attempt that.
(https://forestryforum.com/gallery/albums/userpics/33430/DSCF0974.JPG)
(https://forestryforum.com/gallery/albums/userpics/33430/DSCF0973.JPG)Also any advice on running this little diesel would be appreciated. PC
Possum, you have a 3-71 Detroit diesel if in decent shape will serve yeoman duty on your belsaw. Myself I would go the jackshaft route. Flatbelts were used when they had nothing else. It would have to be very tight and the flapping when on and off load is hard on the arbor that is none too stout to begin with. I would turn the engine around and set it up with a jackshaft with a universal joint to the arbor and multiple "V" belts jackshaft to engine. Frank C.
Possum and Frank, define jack shaft? Being the engine has a v groove pulley on it, wouldn't you just go with v groove belts from the engine to a v groove sheave on the saw? Maybe the belsaw is set up different than what I am used to, I have never seen one.
Dave C
Belsaws Were designed to run off tractor PTO which is opposite rotation of engine at rear. Have been told that with some conversion a Detroit Diesel will run either direction
Ah, got it, thanks. Yes the 3-71 will run either direction but from what I understand it takes rework of the gears, etc. and by the time you get all of that done you would wish you had figured some other solution out. At least my uncle who has been a diesel mechanic for 40+ years says so. He had someone recently ask him about reversing a Detroit and he ran them off with a stick.
Dave C
Big stick to I bet :D
I'm not sure that the engine will run in either direction without a cam change at the very least.
The -71's will run in either direction with a cam/balance shaft swap as well as a few other odds and ends. The only parts you'd need to purchase would be an opposite rotation starter and gaskets. It isn't something that is done quickly however. An experienced mechanic will take two days to do it. Like others have stated, I'd run a jack shaft arrangement if you need an opposite rotation. It looks like that one is set up to run counter clockwise (facing the output of the PTO).
-lee
You can get a gear reduction box that replaces the clutch unit. It will turn opposite of the engine. It would be just like using a tractor pto to run the mill.
That unit looks bullet proof!
Detroits will run backwards!
I used to drive a 1974 GMC Semi with a Detroit. I was backing under a very heavy loaded trailer and it stalled the engine then shot me back out like a bar of soap!
Smoke started coming out of the intake and I had 2 speeds forward and 10 in reverse!!
Having heard about it from old truckers I knew what to do. SHUT it down immediately! Two problems, it will burn the air cleaner and worse problem is the oil pump is running backwards and not pumping oil.
The old Detroits were two cycle.
Quote from: bandmiller2 on July 12, 2014, 09:21:13 PM
Possum, you have a 3-71 Detroit diesel if in decent shape will serve yeoman duty on your belsaw. Myself I would go the jackshaft route. Flatbelts were used when they had nothing else. It would have to be very tight and the flapping when on and off load is hard on the arbor that is none too stout to begin with. I would turn the engine around and set it up with a jackshaft with a universal joint to the arbor and multiple "V" belts jackshaft to engine. Frank C.
That sounds like the best solution, I am sure I will let the engine run in the direction it has for decades however it is interesting to know it could be reversed. Thanks for the comments and wish me luck on hunting a shaft and pulley. PC
You might check the control panel for an emergency stop. ??
They also can "Run Away".
I don't remember the exact problem but something about sucking the engine oil from the pan.
The Semi that I drove had a STOP button and an EMERGENCY STOP cable. The cable would block the intake so the engine could not get air to run.
If you google, there are some u-tube videos of run aways that are scary!
Baileynet.com has some great prices on pillow blocks and is located in Knoxville.
I have had an account with them for a few years and they have great service and fast shipping.
Keyway shafting is easy to find. I buy 1" X 6' regularly from a powertrane shop locally that does a lot of transmission/PTO repairs.
AND, Surplus Center has good prices on pulleys and sheaves.
If an older Detroit has not run in a wile its good form to remove the valve cover and check if you can rotate the rack easily by hand. The amount of fuel is controlled by the rack and how it positions the injector. When engine is shut down the governor spring holds the injectors to full fuel when the engine starts the governor counteracts that spring. If they lay fallow for a long time an injector can freeze full fuel and hold the others open. Frank C.
Possum, its very practical to use a truck driveshaft for a jackshaft if you figure how to attach bearings and pulley to the engine end. Frank C.
Someone may have mentioned it and I missed it, but your going to have to change the fuel pump with one of the opposite rotation if you change the rotation of the engine.
Bandmiller Sounds like you also been around a Detroit runnaway 8) 8)
Yup Cappy and its unnerving, many lads get in trouble with the buffer screw too. Frank C.
In case you have never seen it, this is only one of many!-
http://www.youtube.com/watch?v=8M1o2rpO_JY
When I brought my Belsaw home it had to flat belt system. I changed the drive system to pulleys and v belts. I had to turn the engine around and I used a jack shaft to achieve the correct rotation. Check out my photo gallery. Simple math will give you the correct pulley size and a hand held photo tack will dial everything in for you.Good luck.
I watched my Dad ride a runaway 6v92 once. He checked the rack, as always, before starting. Everything moved as it should. He was standing on the frame rail of the truck when it started. It idled nice for a few seconds then... WHAM... away she went. His pant leg was caught on something and he couldn't get to the shutdown cable. It was awful! Another mechanic ran over and choked her out :D I was laughing my butt off. He didn't think it was too funny >:(
-lee
Is there any better type of air filter available for these old detroits?
I believe Donaldson makes paper element filters for Detroits. My 353 is running the original oil bath filter. It seems to be very effective.
Tripp
Paper air cleaning elements wile effective are expensive. You are better off with the old oil bath you can clean. What helps is A precleaner often used on aggy equipment used in dusty areas. Detroits move a lot of air and the filtration is important. What also helps is to have the engine in a "clean room" with outside air, this also cuts down on the noise factor and gives you a warm snuggy place in the winter. Frank C.
Oil Bath Filters while old technology are probably the best filter you can get!
They are messy to service but give complete filtering. It's amazing all the crud you have to dig out of the sump when you clean them.
Run away Detroit is something that lingers on ur mind fer a bit. Other than that they seem to be bullet proof
You hear many run away Detroit stories but I've never heard of one coming apart. A Detroit will ether be good or bad, one that has lost coolant and overheated will be a problem child. After an overhaul or governor work I would always clamp a round jaw vice grip on the rack rod so if I let go it would fall to no fuel. Have someone else crank it but I would have it by the short hairs. Alas the old two cycle Detroits have gone the way of the doo-doo bird, parts once so common and cheap are now a special order. Frank C.
Quote from: StimW on July 13, 2014, 10:24:27 PM
You might check the control panel for an emergency stop. ??
They also can "Run Away".
I don't remember the exact problem but something about sucking the engine oil from the pan.
The Semi that I drove had a STOP button and an EMERGENCY STOP cable. The cable would block the intake so the engine could not get air to run.
If you google, there are some u-tube videos of run aways that are scary!
They are fun!! Always check your linkage on the fuel rack to make sure it is tight. Check for smooth operation of the rack. Sometimes the ball joint on the linkage gets worn on will fall off causing a runaway. Had a 6-53 Silver gets crazy on me once! Funny thinking back, but not at the time.
Trever