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I was able to obtain the specifications of two out of three of VAM's most well known and used camshafts, the inhouse 266º unit for standard production vehicles and the also inhouse high performance 302º degree unit. The third most common unit used by VAM being the 244º unit originally designed in the United States by AMC and used in the VAM 232s and 199s. These specs come from the 1981 VAM Factory/Dealership Tech Manual.
The manual was obviously in Spanish, I did my best to translate the engineering jargon to its correct English terms. If anyone notices any mistake in this department please let me know.
Stock 266º camshaft
Introduced in 1969 in the also new VAM 252 six cylinder (1969-1972) based on the AMC 232. Used in all VAM 258 sixes (1973-1986) and all VAM regular production 282 sixes (1971-1986). Compression ratio used wth this camshaft ranged from 7.6:1 through 9.8:1.
High Performance 302º camshaft
Introduced in 1967 as part of VAM's own six cylinder Go Pack designed by VAM's engineers and pilots. It was available as a dealership option for virtually ANY VAM engine ranging from the 199 all the way to the 282. Compression ratio used with this camshaft ranged from 8.5:1 through 9.8:1. It would become factory equipment in two models, the 1979 American 06/S (Concord two-door sedan with a Hornet SC/360-like focus) plus the 1980-1981 Rally GT (Spirit GT coupe, high performance version).
STANDARD UNIT
Length Slack:
Zero (0) with the engine in operation.
Bearing tolerance:
0.025 to 0.076 mm
0.001 to 0.003 inches
Standard Pivot Diameter:
Number 1 - 51.537 to 51.562 mm
2.029 to 2.030 inches
Number 2 -
51.283 to 51.308 mm
2.019 to 2.020 inches
Number 3 -
51.029 to 51.054 mm
2.009 to 2.010 inches
Number 4 -
50.775 to 50.800 mm
1.999 to 2.000 inches
Gas Pump Eccentric Cam Diameter
41.021 to 41.275 mm
1.615 to 1.625 inches
Maximum Lobe/Cam Lift
6.756 mm
0.266 inches
Valve Adjustment
Intake
Opens - 16º30' Before Top Dead Center
Closes - 69º30' After Bottom Dead Center
Exhaust
Opens - 62º30' Before Bottom Dead Center
Closes - 23º30' After Top Dead Center
Valve Overlap
40º
Duration of the Intake and Exhaust Event266º
HIGH PERFORMANCE UNIT
Length Slack: Zero (0) with the engine in operation. Bearing tolerance: 0.025 to 0.076 mm 0.001 to 0.003 inches Standard Pivot Diameter:
Number 1 - 51.537 to 51.562 mm 2.029 to 2.030 inches Number 2 - 51.283 to 51.308 mm 2.019 to 2.020 inches Number 3 - 51.029 to 51.054 mm 2.009 to 2.010 inches Number 4 - 50.775 to 50.800 mm 1.999 to 2.000 inches Gas Pump Eccentric Cam Diameter 41.021 to 41.275 mm 1.615 to 1.625 inches
Maximum Lobe/Cam Lift 7.679 mm 0.298 inches Valve Adjustment IntakeOpens - 36º Before Top Dead Center Closes - 86º After Bottom Dead Center ExhaustOpens - 86º Before Bottom Dead Center Closes - 36º After Top Dead Center Valve Overlap72º Duration of the Intake and Exhaust Event302º
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Mauricio Jordán
Cuando no se es una empresa famosa se deben hacer mejores automóviles.
- Vehículos Automotores Mexicanos S. A. de C. V.
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