1941 John Deere HN - Investigating Cylinder Head and Engine Block Issues Part 1 of 2

As was shown in the previous blog, the engine block has a serious crack in it. The previous owner advertised that the head was cracked, and when I got the tractor going in the last blog, the right cylinder was also not firing so there are at least a couple things going on with this tractor. My current job is to see if the head is serviceable, and just make a general assessment of the engine.

Getting the head off is fairly straightforward, but a bit time-consuming. The carb has to come off, and the exhaust pipe needs to be disconnected. Then the valve cover and breather are next.

In this next photo below, take a look in the bottom water passage. There are actual chunks or balls of rust. Yet another reason to use antifreeze and not plain water in these old tractors. Glad I'm delving into this. Just for info, in the photo below I indicated with four arrows (external nuts) and two circles (internal nuts) where the head studs are, seven in all.

One thing of note, when I was loosening the valve adjusters, I noticed one push rod on the right side cylinder wasn't seated in the rocker arm cup. I don't know if it just happened when I loosened the adjuster or if it's been that way for a while. If it didn't just happen, that would be the issue with that cylinder not firing. I haven't been inside a two cylinder John Deere in ages, so when I pulled out the push rods, I was shocked at how long they were. About 30 inches. Wow.

This next photo below shows the head and manifold off the tractor. It ain't light.

The cylinder on the left in the next photo below is the right cylinder that wasn't firing. There is a bunch of garbage laying in the bottom of the cylinder. Hopefully I can figure out what it is and where it came from.

That doesn't look so good.....

Here's a shot of the tractor minus the head.

And here is a better look at the crack in the block. Yuk. I am going to try and patch it up with JB Weld. I've heard people use it fairly frequently on cracks such as this. The main reason this fix works well is that the cooling system on these old JD's aren't pressurized so the glue doesn't have to hold back much, if any, pressure.

It's pretty amazing the force of water freezing.