Short block assembly resumed and was completed today-
I ran into a snafu last night; when I lapped the valves, I found that the intake valve guide was not concentric with the valve seat. I made a quick trip with the block to the machine shop touched it up. My assumption is that this is what previously ended the life of the engine in OEM form, as it repodtedly used oil. If the valve guide and valve seat are not concentric the valve head will try to find "home" until it works the valve guide wider, and then increasing oil consumption. With that solved, reassembly resumed with installing SKF 6308-C3 bearings, a high quality USA-made bearing.
The exhaust valve recieved a light coat of anti-sieze and the intake, a light coat of assembly oil. Valves were installed and the cam was installed with two .010" shims. Next came the other bearing was installed in the bearing plate, and the crankshaft assembled to that. After trial & error the gasket and 2 paper shims were installed to get correct crankshaft end play.
Next the Super Cub billet rod and JE piston were assembled. Checks for ring gap and clearance were made as well. Spiral locks were assembled to retain the wrist pin and the bearing was installed on the rod. The assembly was dropped down the bore and assembled to the crankshaft. With the longer rod combination the skirt of the bore needs to be clearanced, note the pictures from yesterday. I completed that operation before the block was bored. Here's a shot looking at the block to rod clearance:
So as it sits tonight, here's the short block, assembled with the exception of bolts being torqued- I'm still trying to find the correct torque for the four rod bolts on the Super Cub rod, if anyone knows, please e-mail me.
Here's the "insides"
You'll notice that there are no balance gears installed, this engine was out of a very late production 1450. The bores for the balance gear pins exist, but still have the factory plugs installed in lieu of the shafts. Kirk Engines balanced the crankshaft to work with the piston/rod combination. Every part on this engine is new, and going foreward with the rest of the build I'm holding as close to "new" as possible with the intention of leaving a little chance of any small failure.
The next steps over the next few weeks will be to get a stator (I'm tempted to get the 25A stator ILO the factory 15A stator), record the cam specs, set the ignition timing, and assemble the mechanical fuel pump. I'm currently trying to find out if an Kohler 10hp Magnum head has adequate room for the large K321 exhaust valve I have, so far no answers are to be found. With any luck I'll be able to break the engine in inside yet before spring.
This engine is part of a 5-year long project building a Cub Cadet with the sole purpose of plowing (the 141 Wheatland as it has been known). Though the tractor will appear somewhat custom, as many factory Kohler and IH parts are used, just not necessarily as it left the factory. For lack of a better term, a restomod Cub Cadet.
