I want to do a complete tear down and overhaul this spring and noticed tonight that the overhaul kits for the WD's tend to be more expensive than the WD45's.  Since I wanted  the HP of the WD45 anyway, and I already have the WD45 body and parts, I was wondering what the harm would be in upgrading the engine.

I did some studying tonight and was hoping that someone with more experience could weigh in on this for me.  The 201 and 226 engines are essentially the same with the exception that the 226 has a different piston, and a different camshaft.  The WD45 also had a larger carb and radiator, but I already have those since the tractor is a WD45 and the only thing that was swapped seems to be the block.

I need to buy an overhaul kit anyway, so the sleeves, pistons, rings, etc. would all be included if I bought the WD45 overhaul kit rather than the WD.  A camshaft for a WD45 runs about $150 on ebay or I could purchase one from a guy here locally that has a lot of used parts.  What am I missing, is it really this easy to get the extra horsepower if you are doing a complete overhaul anyway?

The tractor seems to run fine, just a little rough.  It had a pretty nasty coolant leak at the water manifold so I started by removing the hood, intake/exhaust manifold, and the water manifold.  I found that there were no gaskets on any of the ports for the exhaust manifold and that the ones at the water manifold had long since failed.  From there I was curious to find out what condition the inside was in so I removed the valve cover and the head.  

Some of the sleeves have a slight ridge around the tops where the piston stops (taper?) and some very slight black buildup (carbon?) in those areas as well.  Cleaning out the carbon seems to be pretty easy and I checked out a cylinder hone from a local auto parts store and planned to run it around the top of the cylinders a couple of times to cut down on the taper.  I don't expect perfection here and do understand that a purist would tell me to put in new sleeves, pistons, and rings, which I may still do, but in the short term I am going to try the less expensive route and see if I can get it running until springtime.

The head also had some carbon buildup and the number 2 piston's larger valve (exhaust?) had a decent amount of carbon buildup (3/16") on both its face and the stem.  The rest of the valves seemed to be okay, but with varying amounts of carbon.  I plan on dipping each of them and removing everything that I can and then lapping the valves with some compound.  Again, not a purist restoration, but certainly better than what it was.

I was also having some trouble with the throttle not engaging the carburetor very well so I removed the radiator to get at the governor cover.  I was wondering if maybe I hadn't broken a spring or weight in the governor, but was stumped once I opened that up.  In the end, it turned out that I needed to readjust the throttle linkage so that it would push and pull correctly.  Once I took care of that, it would appear that the throttle is pushing and pulling on the carb as expected, but I haven't had the tractor back together to give it a trial run.

I will check the stoke of the engine tomorrow.

Can anyone give me the rough dimensions of the short versus the tall head for these engines?

Sounds like you are having fun.

Feel free to call for another point of view.