After giving the engine choice more thought I decided to tear down the engine that I tested for the Blue Angel and install one of my Nelson liners and pistons. The aluminum chrome Nelson liner is almost two ounces lighter than the stock ABC OS liner and has improved porting. That may result in an ounce or so less tail ballast too! While I had it apart I decided to replace the bearings because even though they felt and sounded good they didn’t look very good on the outside.

I expect most of you following this thread are very experienced at doing engine rebuilds but I thought I’d share my approach to the process.

My usual process is to remove the head (need to use an Allen wrench that is in like new condition to fit the bolts), remove the pump and drive washer. If the sleeve is stuck tight leave the drive washer on and install the prop. Insert a small piece of plywood between the top of the piston and the exhaust port. Turn the prop with a light force so the piston contacts the plywood and gently push the sleeve up.

After the sleeve is out turn the crank to top dead center and pull back on the rod with your finger. The piston should move to the back of the case, the rod should slide back on the connecting rod and the rod should almost fall off the crank shaft crank pin. Sometimes gunk can build up on the connecting rod preventing the rod from sliding all the way to the inside of the piston. Believe it or not, the professional engine rebuilders that I have talked to use a little heat from a propane torch on the bottom side of the piston through the back of the engine to free the rod. It sounds brutal but it has worked for me many times without any negative results. Just be careful with the heat.

Next I put the engine in an oven set to 350 degrees and let it heat for ten minutes or less. I remove the engine and hold it in a small towel and slap the back of the engine down on a block of would that is covered with a towel. Be careful. 350 degrees is darn hot!! With a good hard rap the crank should move back taking the back bearing along with it. Once the crank gets to the back of the case it should easily slide out with the bearing and you should be able to slide the back bearing off the crank shaft with a little force. I accomplish this by tapping the nose of the crank shaft on a piece of wood.

While the case is still hot I use a ½ inch dowel to push the front bearing out by tapping the case down with the dowel held against a hard surface.

After I get everything apart I clean up the case and head with Dawn Power Dissolver. Be careful that you do not leave the Dawn on the parts very long or it may tarnish the aluminum. At any rate, if it does get tarnished you can use Twinkle brand copper cream and a tooth brush to gently scrub the case and it will look like new. It takes a good bit of scrubbing and washing with hot water but the results are pretty impressive.

I do not mess with the pump other than clean it with fuel.

See images below to view the process and the images of the Nelson piston and liner kit. Unlike the OS piston the Nelson piston does not have an arrow on top pointing to the exhaust port and can be installed on the rod either way.

My new bearings are on their way from Boca Bearing and I will cover the assembly shortly.

To be continued…