D301 falls on its face

I just bought a farmall 656 with a d301 from a combine installed.

This engine sat around a while, and seems to be in fair condition. Good at best. It burns a touch of oil, the head gasket weeps a little to the outside, and it has a decent amount of blo by.

Glow plugs all work, but any less than 1:45 of glowing and it"s a very grumpy starter. 2:00 or more and it starts up very clean.

Anyway, the motor seems week. I turned the pump up enough to get some black smoke. On the dyno at 2100 rpm (620 pto), it pulls 73 hp. But any lower than 2000 rpm and it falls on its face. If I pull it down to 1800 rpm (540 pto), it only makes 63 hp.

A friend of mine has a 656 with the correct d282, and it is much stronger at or below the rated 1800 rpm than my 301 is.

Was the combine engine"s cam different, or is everything to do with the higher speed in the pump?

Is my engine week down low because of the combine fuel pump, or just because it"s tired?

same cam. re ring it, have pump gone thru, check the injectors. blowby telling me that she needs looked at. someone may have ground the valves n now you may low compression in a few cyls. d301 is a 80-85hp engine at 1900 and 94 at 2640

a friend of mine has one in a 560 and he had to do a lot of work to the air intake , it just couldn't get enough cool air . after that it dynoed 90 hp and has good low end .

Hi
Combine pumps are usually different to tractor pumps, as to how they rev and the govenors. A combine pump is set to give power at full or close to RPMs. A tractor injector pump usually has an auto advance/ retard mechanism built in so the pump gives power right through the rev range.
Not sure on the IH combine motor pump for non auto advance or not, but wonder if it still has the combine pump on. And it needs the tractor one to keep the power on when the revs drop, and maybe it would also need re setting for more fuel to match the combine motor fuel needs as well.
I think it"s more than just worn motor as it falls flat when the revs drop.

I know a guy ran 2 European Deere combines one had a combine motor from factory, the other had a tractor motor fitted after a fire and re build.
Both ran the same crop and field, They had to run the tractor motor one out front, as in heavy crop it plowed on and didn"t drop back rpms in heavy patches. If the factory one was in front the other one near crashed into it running side by side. The only difference in the motors was the fuel pumps and that auto advance in the tractor pump.

Regards Robert

Hi northpuller hows it going. My suggestion is take that motor out and run a 301 gas. Put on 806 manifolds and truck head. I have a truck head in the shop for you. By the way when is the Feversham pull I want to get there this year

Sat sept 13 at 12:30.

My email should be open. If you know where I can get everything to get a gas 301 together I'm interested. I'd also take a gas 263/291.

A RD 450 would be alright too.

What cam and pump are you using? You may have a combine cam ground for >2400 RPM and a tractor injection pump setup for <1800 RPM. Combines are not made to be lugged down below 90% of full RPM, so why would they put in a cam with low speed torque in a combine?