425 Engine Swap idea

[cqaigy2]

Moss's method of starting sound very familiar, except i couldn't find the starting fluid and used carb cleaner and a shorter shot of it.

 

[BAGTIC]

My Robin has not been that reliable. The starter failed while it was still under warranty.

The engine froze up over three months ago and has not run since. Every time my tech calls he is told replacement engines are not available at this time.

I have also had to rebuild two wheel motors and replace the ignition switch.

Diesel Vs. Gas? Some of the larger two cyclinder gas engines (B&S, etc) can if derated and run at less than full power almost match a 25 hp class diesel in torque. Running at 65-75% rpm also makes them much more fuel efficient.

Hydrostatic drives don't need high torque engines, that is what the hydraulic pump is for, to produce increased torque.

 

[J_J]

My Robin has not been that reliable. The starter failed while it was still under warranty.

The engine froze up over three months ago and has not run since. Every time my tech calls he is told replacement engines are not available at this time.

I have also had to rebuild two wheel motors and replace the ignition switch.

Diesel Vs. Gas? Some of the larger two cyclinder gas engines (B&S, etc) can if derated and run at less than full power almost match a 25 hp class diesel in torque. Running at 65-75% rpm also makes them much more fuel efficient.

Hydrostatic drives don't need high torque engines, that is what the hydraulic pump is for, to produce increased torque.

The hydraulic pump has to be matched up to the engine, or you will not see the pumps potential. You can over HP and just loaf along, but if underpowered, sometimes it just will not cut it.

 

[BAGTIC]

My point is that if you need 25 hp you can put in an engine that produces 25 at max continuous rpm or you can use a larger engine rated 35 +/- hp with 25 hp at the peak torque curve, where the best fuel efficiency is, and still have have as much hp and more torque that the straight 25 hp model and at very little more initial coast and better fuel efficiency.

Of course the pump must match the engine. The pump should be selected to fit the engine, not the other way around.

 

[J_J]

My point is that if you need 25 hp you can put in an engine that produces 25 at max continuous rpm or you can use a larger engine rated 35 +/- hp with 25 hp at the peak torque curve, where the best fuel efficiency is, and still have have as much hp and more torque that the straight 25 hp model and at very little more initial coast and better fuel efficiency.

Of course the pump must match the engine. The pump should be selected to fit the engine, not the other way around.

I tend to disagree for this reason. First, you have to plan for what you want the machine to do. Say you want to be able to lift 2000 lbs, and move the machine at 8 mph.. That will determine the thickness and type of metal you use in fabrication. Next you want to know what size cylinders will lift this load, by selecting the correct pump size. Moving the load will take a certain hyd motor for the speed desired, which will dictate the pump size. The HP necessary to drive this pump is calculated, and added to the list of HP necessary to power all the pumps. Then you look for an engine with the available HP to power all the pumps on this machine. If you can find an engine that will fit the frame, you are almost there, however, if you can not find an engine to fit the proposed frame, maybe widening the frame might work.

From all this, you determine the hyd GPM's, pressure, and HP required to power all this, with a safety margin.