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Pontiac LNF specs: 122 ci (2.0L) 4-cylinder, 3.386 x 3.386 in (86 x 86 mm) bore and stroke, 9.2:1 compression. Rated 260 hp, 2007–2009.
The Pontiac 122ci (LNF) is exactly square — 3.3858" bore and 3.3858" stroke are the same — which splits the difference between a high-revving layout and a torque layout. The 3.3858" 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 4 cylinders displaces 30.5 ci (500 cc).
9.2:1 on aluminum heads is low by modern standards and generally happy on regular pump fuel.
It is one of 2 engines in the Pontiac 122ci family, all of them 122 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated at 260 hp across 2007–2009.
| Displacement | 122 ci / 2 L |
|---|---|
| Bore | 3.3858" |
| Stroke | 3.3858" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.2:1 |
| Bore/stroke ratio | 1 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 260 hp |
| Years | 2007–2009 |
| Bore/stroke character | 1.000 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.5 ci |
| Static compression | 9.2:1 — low by modern standards, generally happy on regular pump fuel |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2007 | 260 hp | LNF |
| 2008 | 260 hp | LNF |
| 2009 | 260 hp | LNF |
1 factory vehicle, 2007–2009. Each year opens that model's engine table.