Engine Compression

Warm engine to normal operating temperature. Remove all spark plugs. Disconnect ignition coil primary wire connector. Hold throttle plate fully open. Crank engine and note compression pressure.

COMPRESSION SPECIFICATIONS

Application

Minimum psi (kg/cm ² ) @ RPM

Standard psi (kg/cm ² ) @ RPM

B2300 & B2500

⁽¹⁾

B3000 & B4000

⁽¹⁾

Miata

146 (10.3) @ 300

198 (13.9) @ 300

Millenia ⁽²⁾

2.3L

120 (8.5) @ 250

164 (11.5) @ 250

2.5L

130 (9.3) @ 300

189 (13.3) @ 300

MPV

⁽¹⁾

Protege ⁽²⁾

1.6L

142 (10.0) @ 300

199 (14.0) @ 300

2.0L

119 (8.4) @ 300

171 (12.0) @ 300

Tribute

2.0L

⁽¹⁾

3.0L

⁽¹⁾

626 ⁽²⁾

2.0L

119 (8.4) @ 300

171 (12.0) @ 300

2.5L

141 (9.9) @ 250

202 (14.2) @ 250

⁽¹⁾	Lowest compression reading should not be less than 75 percent of highest compression reading.

⁽²⁾	Difference between cylinders should not be more than 28 psi (2.0 kg/cm² ).