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ENGINE / CALCULATOR

Bore / stroke /
CH calculator.

Match piston compression height, connecting rod length and stroke to a selected block deck height. The calculator shows deck clearance, engine displacement and the compression height required for zero deck.

01 /

Cylinder & crankshaft

in
in
02 /

Connecting rod & piston

in
Center-to-center connecting rod length.
in
Measured from wrist pin centerline to piston crown.
03 /

Block

in
Measured from crankshaft centerline to the block deck surface.
How does the calculation work? + −

Piston position at top dead center is determined by connecting rod length, half of the crankshaft stroke and piston compression height.

Stack height = rod length + stroke / 2 + CH

Deck clearance is calculated by subtracting the stack height from the block deck height.

Deck clearance = deck height − (rod length + stroke / 2 + CH)

A positive result means the piston crown remains below the block deck. A negative result means the piston protrudes above the deck surface.

Zero deck means that the piston crown is level with the block deck surface at top dead center.

Zero deck CH = deck height − rod length − stroke / 2

Engine displacement is calculated from bore, stroke and cylinder count.

Displacement = π / 4 × bore² × stroke × number of cylinders

Deck clearance is not the same as minimum piston-to-head clearance. Piston-to-head / quench clearance also depends on factors such as compressed head gasket thickness. Always verify final mechanical clearances for the specific engine before assembly.