Saturday, June 24, 2023

1986 John Deere 650 Tractor Engine Reassembly

Parts for my engine rebuild came in so it's now a simple matter of putting everything back together, right? First up was to press the new main bearings into the engine block. The front bearing presses directly into the block and the back bearing presses into a flanged casting that then bolts to the back of the block after the crankshaft is installed through the rear of the block. There is a funky center bearing on the crankshaft that is held in place by a large circular split casting. The crankshaft is installed into the block, then the center split casting is bolted to the block with one bolt. The rear bearing and seal flange is then bolted to the block. Here's a photo of the flange when I was removing the bearing:

Next was to get the rings onto the pistons and install the pistons/rods/rod bearings into the block and torqued onto the crankshaft. All bearings and rings were purchased in standard sizes, as the crankshaft and cylinders were within the wear tolerances referenced in the service manual. It really is pretty remarkable that an engine with 5,000 hours on it is still in such good condition.

After the pistons went in, the head went on. Then the valve push rods and rocker arms were installed and adjusted to .008-inch. After that the fuel injectors were installed. It's starting to look like an engine again.

The front cover goes on next. I had to find some o-rings (the green things in the photo below) for the oil pump ports, as there weren't any in the gasket kit.

The injector pump is mounted on the cover and the injector lines are installed, then the water pump is installed, and the oil pickup and pan are also installed. That pretty much finishes off the engine except for the hydraulic pump, and I need to make a gasket for that since there also wasn't one of those in the "complete" engine gasket kit. I wish they'd list all the gaskets and o-rings that come in the kit, but they don't. Anyway, this next photo shows the engine pretty much ready to take off the engine stand and get the flywheel and clutch installed.

I pulled out the "thermo-start" gizno from the intake manifold, as it didn't work entirely as it should. In theory, when the thing is energized, diesel fuel drips onto a heated coil and the fuel is supposed to ignite, giving the intake some warm air for cold starts. Mine never did catch fire like it should, so I thought I'd see if anything was obviously in need of help. I think I found the problem. There are a series of holes around the outside of the shroud which were plugged solid with crud.

Here's a little of the crud I was able to pick out of the holes.

That looks much better. Hopefully I'll see some flame the next time I try this thing out.

No comments:

Post a Comment