Engine variations
Posted: Mon Nov 02, 2015 1:19 pm
I am wondering what variations of the gas engine there are.
My parts book mentions:
1. Tropical with compression ratios of 7.2:1, 83.5 HP
2. Tropical with compression ratio of 7.5:1, 85.5 HP
3. Normal with compression ratio of 7.5:1, 87 HP
4. Normal with 7.8:1 compression ratio, 90 HP
My shop manual gives jetting for four carburetors, one to meet ECE 76, one to meet ECE 79, one exempt from ECE due to truck being over 3.5 tons, and one for "hot climates" which also seems to be exempt from ECE. The "over 3.5 tons" and "hot climate" seemed to be jetted richer and have the "big screw" throttle body.
There are 4 camshaft numbers in the parts book. No clear indication on how they are different. The torque curves of the "standard" and "hot climate" engines look as if there is something else going on other than richer jetting so maybe they had different cams.
Can anybody make any sense of this?
My parts book mentions:
1. Tropical with compression ratios of 7.2:1, 83.5 HP
2. Tropical with compression ratio of 7.5:1, 85.5 HP
3. Normal with compression ratio of 7.5:1, 87 HP
4. Normal with 7.8:1 compression ratio, 90 HP
My shop manual gives jetting for four carburetors, one to meet ECE 76, one to meet ECE 79, one exempt from ECE due to truck being over 3.5 tons, and one for "hot climates" which also seems to be exempt from ECE. The "over 3.5 tons" and "hot climate" seemed to be jetted richer and have the "big screw" throttle body.
There are 4 camshaft numbers in the parts book. No clear indication on how they are different. The torque curves of the "standard" and "hot climate" engines look as if there is something else going on other than richer jetting so maybe they had different cams.
Can anybody make any sense of this?