Engine rebuild - 1983





Gray Marine Lugger Light 4

69 cubic inch

16 hp @ 1800 rpm max


Still works great 29 years later!


The crankshaft was turned 0.010 under size (both mains and crank journals), and new bearings were installed


The engine was bored 0.072 over size to accept universal Atomic 4 pistons (0.01 over size).


This was done because over size pistons were not available for this displacement engine. New bushings were installed in the wrist pin end of the connecting rod and bored to accept the Atomic 4 wrist pins.


The camshaft bearings were replaced; four new exhaust valves were installed and all valves were reseated.


The generator was used as a power take-off to drive the existing water pump and a new 65-amp, 12-volt alternator at 4 times crankshaft speed. (The system was 6 volt previously). The field winding, brushes, etc. were removed from the generator.


The flywheel-to-generator power take-off is driven by 2 V-belts, and the generator-to-alternator take-off is driven by a timing belt. The water pump is driven directly by the generator power take-off.


The starter is the original 6-volt, which cranks the engine faster with the 12-volt system.

The original




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