Buick LY7 Specs: 3.701 x 3.37 in, 255 hp

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Buick LY7 specs: 217 ci (3.6L) 6-cylinder, 3.701 x 3.37 in (94 x 85.6 mm) bore and stroke, 10.2:1 compression. Rated 255 hp. DOHC. Rod ratio and piston speed.

The Buick High Feature V6 (LY7) is oversquare — the 3.7008" bore exceeds the 3.3701" stroke by 9.8% — a layout that favors airflow and RPM over leverage at the crank. The 3.3701" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 36.2 ci (593 cc).

10.2:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.

It is one of 4 engines in the High Feature V6 family, the smallest at 217 ci. 2 factory variants share these dimensions, rated at 255 hp. Factory fitments include the Buick LaCrosse, Buick Enclave, LaCrosse and 1 other.

Dimensions

Displacement217 ci / 3.6 L
Bore3.7008"
Stroke3.3701"
Cylinders6
Compression ratio10.2:1
Bore/stroke ratio1.098

Construction

Block materialaluminum
Head materialaluminum
ValvetrainDOHC
Fuel typegas
Advertised HP255 hp

What these numbers mean

Bore/stroke character1.098 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM3,370 ft/min — conservative for a street engine
Displacement per cylinder36.2 ci
Static compression10.2:1 — in the range that usually runs on pump premium

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Variants sharing these dimensions (2)

These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.

YearAdvertised HPCode
—255 hpLY7
—255 hpLY7

Vehicles (4)

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