1968 Tecumseh H50 "Hot Rod" Build

Did you deglaze the cylinder before you installed the new rings?
I used a piece of sandpaper to give it as good a crosshatch as I could manage by hand.

Moot point, because I actually ended up putting another set of rings in, because it turns out the set I had put in there previously were used.

This time, I found a 3-stone hone and gave it a good cross-hatch before installing an NOS set of standard rings. 20231117_154743.jpg
Well, the rings I put in the go-kart HH60 got ruined because I ran a synthetic oil that says "Not for engine break-in" right on the bottle.

It ran fine at first, but started smoking worse and worse, so I ordered the same set of rings from the same seller on ebay. I explained why I bought another set so soon, and he upgraded me from a set of aftermarket rings to an OEM set of chrome-plated rings, for no additional cost!

I tore down the engine, and the rings were toast. Oil everywhere in the combustion chamber and bore, and the top and bottom rings had about 3/16" of ring end gap!

Oh man. At least the bore cleaned up really well with a quick hone, and the ring gaps with the new OEM Tecumseh rings were good. The Motorsports rod's bearing insert was still in perfect shape, thankfully.

I also bought an H70 MCR cam, and already had an NOS set of H70 lifters, so when the cam came in today I installed it, ground the intake valve stem end to set correct clearance (exhaust lash was dead on, I replaced the intake valve a week ago and lash needed opened up 5-6 thou), and put the long block together in my shed. I made sure to put in 20 oz. of Royal Purple engine break-in oil this time.

Well, it fired up after some fiddling with the ignition switch, and I held it at mid throttle to break in the cam/lifters.

After that was done, I adjusted the idle speed and mixture, and took it for a quick spin around the yard. IT DOESN'T SMOKE! Power is better, the idle is a lot smoother since the plug isn't constantly getting fouled by oil passing by the rings.