I'm looking do a 40hp tractor conversion. I've managed to find, and have now bought, a David Brown 880 Selectamatic with a tired engine - rest of the tractor is mechanically sound (so I'm told), but it does need some TLC (definitely doesn't look anywhere near as good as the one in the photo below 
). So, here's my plan for the conversion so far:
If you look at the David Brown 880 picture below, it shows you the tractor and how the major engine and transmission components are layout.
![Image]()
And, the following gives an exploded view of those major components:
![Image]()
![Image]()
My plan is to remove the engine - basically everything above the sump frame including the crankshaft. The sump frame will remain, as it provides the structure for the front frame (and front axles and wheels) to stay connected with the rest of the tractor. Although the sump frame may need some reinforcing, which I'll hopefully be able to do when mounting the electric motor and structures for holding batteries.
![Image]()
![Image]()
The flywheel and double-clutch, one for PTO and one for transmission, will remain (NB. the orientation of the double-clutch diagram is 180deg out - i.e. the PTO friction plate end goes into the right-hand side of the flywheel in the left diagram). So, the electric motor will be attached to the flywheel - I will need to get a coupling manufactured to match how the crankshaft was bolted to the flywheel.
However, as the engine normally runs from 700 to 2000rpm, I expect a reduction gearbox, or pulleys and belt, will need to be used between the electric motor and the flywheel. Plus the reduction box/pulleys-&-belt will also allow the motor to be mounted above the sump frame, as I don't expect there will be enough room down in the sump frame where the coupling will attach to the flywheel.
Anyway, that's my plan thus far (still waiting for the tractor to arrive). But, what do you think of my plan thus far?
Next step, researching electric motors (I'm think around 20kW?), controllers and batteries.
). So, here's my plan for the conversion so far:If you look at the David Brown 880 picture below, it shows you the tractor and how the major engine and transmission components are layout.
And, the following gives an exploded view of those major components:
My plan is to remove the engine - basically everything above the sump frame including the crankshaft. The sump frame will remain, as it provides the structure for the front frame (and front axles and wheels) to stay connected with the rest of the tractor. Although the sump frame may need some reinforcing, which I'll hopefully be able to do when mounting the electric motor and structures for holding batteries.
The flywheel and double-clutch, one for PTO and one for transmission, will remain (NB. the orientation of the double-clutch diagram is 180deg out - i.e. the PTO friction plate end goes into the right-hand side of the flywheel in the left diagram). So, the electric motor will be attached to the flywheel - I will need to get a coupling manufactured to match how the crankshaft was bolted to the flywheel.
However, as the engine normally runs from 700 to 2000rpm, I expect a reduction gearbox, or pulleys and belt, will need to be used between the electric motor and the flywheel. Plus the reduction box/pulleys-&-belt will also allow the motor to be mounted above the sump frame, as I don't expect there will be enough room down in the sump frame where the coupling will attach to the flywheel.
Anyway, that's my plan thus far (still waiting for the tractor to arrive). But, what do you think of my plan thus far?
Next step, researching electric motors (I'm think around 20kW?), controllers and batteries.
