JOHN DEERE 790D seized up

[davecampbell]

I bought a seized up 790D today. My thought were to pull off the pumps to see if they were seized or the motor. If there is an easier way to determine which it is, I'm all ears.

 

[excavator]

Since there is a rubber coupler between the engine and pumps, if it's the pump, I would think that there would be a slight engine movement if you try to bar the engine over. But, either way you are going to have to separate them anyway.

 

[davecampbell]

I couldn't budge the motor at all, and you are correct, pulled the pumps and they spin free. It's a john deere 6-466AT. Can I buy a 466t and just use my turbo and cooler or is it important to find a after cooled motor?

 

[posrepair2013]

pull injectors or glow plugs if it has them. Than try and bar engine over maybe hydro locked

 

[davecampbell]

Shouldn't a hydrolocked motor be able to turn backwards?

 

[excavator]

I couldn't budge the motor at all, and you are correct, pulled the pumps and they spin free. It's a john deere 6-466AT. Can I buy a 466t and just use my turbo and cooler or is it important to find a after cooled motor?View attachment 220548

Not sure what all the differences would be. Do you know what it came out of? If you knew that you could go to Deere parts and compare what's inside (pistons ect.) and injection pump ect. Otherwise a pic of the serial number plate might work.

 

[Wilson892]

Seems to me when I did the 466 in my 892 there was a different head and valves for a turbo intercooled engine. Tore mine down and rebuilt wasn’t that expensive compared to a rebuilt exchange motor.

John

 

[davecampbell]

Not sure what all the differences would be. Do you know what it came out of? If you knew that you could go to Deere parts and compare what's inside (pistons ect.) and injection pump ect. Otherwise a pic of the serial number plate might work.

Here are the 2 data plates from the motors.

 

[mg2361]

6466AT (790 engine built in Dubuque) is turbocharged and after-cooled. 6466TH (built at the Harvester Works in Waterloo) is just turbocharged. The "TH" engine looks to be out of a combine and will probably fall short on horsepower (30HP or so less). That is a guess since the engine is old enough that finding specs for it is difficult.

 

[davecampbell]

6466AT (790 engine built in Dubuque) is turbocharged and after-cooled. 6466TH (built at the Harvester Works in Waterloo) is just turbocharged. The "TH" engine looks to be out of a combine and will probably fall short on horsepower (30HP or so less). That is a guess since the engine is old enough that finding specs for it is difficult.

Thank you sir. Yes, you are correct the motor I found is in a combine. On my komatsu i can adjust how heavily the hydraulics load the motor, would that be a setting that is available on this John Deere also? Im thinking I could turn it down to make up for the 30 hp it would be lacking.

 

[mg2361]

Yes, it can be adjusted. You will need the Operation and Test manual TM1395.

 

[davecampbell]

Number 3 rod bearing totally gone and one of the main bearings 1/4 turn. Not thinking this crank can be saved. I'm having a hard time getting deere parts online. I'd like to see if I could put this head on the combine bottom end.

 

[Tyler d4c]

Personally I would get the combine engine swap the camshaft if there a different on and put the excavator fuel system on it and run the combine engine

 

[davecampbell]

I thought about that, maybe even use the head and after cooler too.

 

[davecampbell]

Turns out there are several different engine configurations in a 6620 combine. One of them uses the same piston that my motor does. In which case I think I can drop my head cam and turbo onto it. But I don't know how to figure out which configuration it is. the one with the blue arrow is the one that I need.

 

[mg2361]

Some pistons had the part number on the underside of the piston. And some pistons also had it etched into the top. If you don't see it on the bottom clean the top of the piston off and look. Liners also have a part number etched into the top. Clean off the raised portion (above the fire ring surface) with sand paper and see if it is. This engine might be before they started doing that, but worth a look.