See other engines in this family
Pontiac 98ci specs: 98 ci (1.6L) 4-cylinder, 3.228 x 2.98 in (82 x 75.7 mm) bore and stroke, 9.64:1 compression. Rated 65 hp, 1984.
The Pontiac 98ci is oversquare — the 3.228" bore exceeds the 2.98" stroke by 8.3% — a layout that favors airflow and RPM over leverage at the crank. The 2.98" stroke does not reach 4,000 ft/min of mean piston speed until about 8,050 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.611 is in the range most production engines fall in. Each of the 4 cylinders displaces 24.5 ci (401 cc).
9.64:1 is in the range that usually runs on pump premium.
It is one of 2 engines in the Pontiac 98ci family, all of them 98 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 98 ci / 1.6 L |
|---|---|
| Bore | 3.228" |
| Stroke | 2.98" |
| Cylinders | 4 |
| Compression ratio | 9.64:1 |
| Rod length | 4.8" |
| Rod ratio | 1.611 |
| Bore/stroke ratio | 1.083 |
| Piston deck clearance | 0.005" |
| Induction | 1-2 |
|---|---|
| Advertised HP | 65 hp |
| Years | 1984 |
| Bore/stroke character | 1.083 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,980 ft/min — conservative for a street engine |
| Rod ratio | 1.611 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 24.5 ci |
| Static compression | 9.64:1 — in the range that usually runs on pump premium |
| Intake valve diameter | 1.54" |
|---|---|
| Exhaust valve diameter | 1.26" |
| Chamber volume | 41 cc |
| Rocker ratio | 1.6:1 |
| Lifter type | hydraulic |
Each link opens the calculator with this engine's specs already filled in.