Re: Compression ratio L-79 350HP compared to 300HP
Good photo of how to measure deck clearance, which should be done on all eight cylinders before tear down in order to start the compression ratio management process for the rebuilt engine.
The dial indicator is used to set the piston right on TDC, and then the depth mic is used to measure clearance between the block deck and piston crown, which is the flat area around the circumference of the piston. Forged SHP type pistons as shown will usually show a little "rock" due to the larger cylinder wall clearance relative to flat cast pistons, so measure clearance on both sides and adjust the piston as required until the two measurements are the same.
Duke
Good photo of how to measure deck clearance, which should be done on all eight cylinders before tear down in order to start the compression ratio management process for the rebuilt engine.
The dial indicator is used to set the piston right on TDC, and then the depth mic is used to measure clearance between the block deck and piston crown, which is the flat area around the circumference of the piston. Forged SHP type pistons as shown will usually show a little "rock" due to the larger cylinder wall clearance relative to flat cast pistons, so measure clearance on both sides and adjust the piston as required until the two measurements are the same.
Duke
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