1949 Briggs Model WI
I acquired this engine in a batch of five purchased from a gentleman who answered one of my want ads on a local ISP Classified Ads page. Someone had cleaned it up and given it a shotgun paint job at some point. It looks like a carnival ride to me. I'll be restoring it to the factory black color.
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A few contradictions to start with. The serial number indicates this engine was manufactured in April of 1949. The cast numbers and letter in the mag plate indicate August of 1947, and the flywheel date marks are of October 1950. I'm guessing the flywheel is not the original.
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Here are all the internal parts, cleaned and inspected. everything looks good. The parts are the crankshaft, piston assembly, breather assembly, cam and camshaft, exhaust and intake valves with springs tappets and keepers.
Not much to the ignition system. Just the armature coil, condenser and points.
The fuel system is made up of the tank, outlet/check valve, fuel line and carburetor.
The check valve is made up of 4 parts. The tube, valve retainer, valve disc anf the screen.
The carburetor is a simple deal with a rotating bowl inside that acts as the choke. When the hole in the bowl is rotated away from the carb throat the air in is restricted causing the choke situation.
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This early centrifugal clutch was a real challenge to get apart. But after cleaning out a few decades of dirt, rust and paint it's back in running order. I had nothing to work off of, so it was kind of a tear it apart and figure it out thing. Lucky for me it is a simple arrangement.
It was reassembled in this order. First the weights and spring were placed into the matching taper of the base. The shaft was then slipped through the base and the inner, moving pulley half was slid on. The outer stationary pulley half was then pressed onto the shaft and the retaining ring was snapped on the end of the shaft. Last the knob was screwed on the end. The detent ball was placed in the hole in the stationary side and adjusted so the clutch will snap into and out of engagement.
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All of the parts to be painted are sanded smooth and masked. After a few coats of gloss black engine enamel, it's starting to look like something that Briggs built.
The decals are homemade. I do buy the head gaskets for my engines, but the rest of the gaskets are all hand cut. With all the parts painted and gaskets made we're ready to start re-assembling the engine.
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First the valve tappets go in, followed by the cam and camshaft
The camshaft is driven in from the magneto side until it is flush with the block on the PTO side. The using a small amount of sealer the expansion plug is tapped in to seal up the end on the mag side.
Next the crankshaft is installed. The timing marks on the cam gear and crank throw are lined up. Then using a small ring compressor the piston is installed. The "X" on the boss inside the piston goes toward the magneto side of the engine. The rod cap goes on with the screws being torqued to 110 inch pounds. The locks are bent up to the flats on the bolt heads to hold it in place.
The valves are installed next. Always check the tappet clearances before putting the spring retainers on. I check them again after the spring pressure is on, but if their real tight It's better to find out now than to have to remove the springs again. Clearances for this engine are .007 to .009" for the intake, and .014 to .016" for the exhaust. No adjustments were needed for this one. The internal breather goes in here last. There is also a splash guard that covers the whole thing before the cover goes on.
The magneto plate is assembled. Points are set to .020" armature gap is set to .010" A quick check to be sure there is spark, then the flywheel is torqued to 55 foot pounds.
The carburetor and fuel tank are mounted next. Followed by the head, with the head bolts torqued to 140 inch pounds. The sheet metal, centrifugal clutch and fuel line finish it up.
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Finished
New decals and muffler and it's ready to run. But, first the paint will have to cure for a week.