TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - Mexican Camshaft Specifications (266º and 302º)
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Mexican Camshaft Specifications (266º and 302º)

 Post Reply Post Reply
Author
Message
Rambler Mexicano View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/05/2011
Location: Guadalajara
Status: Offline
Points: 628
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rambler Mexicano Quote  Post ReplyReply Direct Link To This Post Topic: Mexican Camshaft Specifications (266º and 302º)
    Posted: Feb/10/2019 at 2:15pm
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 Event
266º


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

Intake
Opens - 36º Before Top Dead Center
Closes - 86º After Bottom Dead Center

Exhaust
Opens - 86º Before Bottom Dead Center
Closes - 36º After Top Dead Center


Valve Overlap
72º


Duration of the Intake and Exhaust Event
302º
Mauricio Jordán

Cuando no se es una empresa famosa se deben hacer mejores automóviles.
- Vehículos Automotores Mexicanos S. A. de C. V.
Back to Top
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 15563
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2019 at 6:49am
The 266 duration cam is about what most aftermarket companies sell as an upgrade from the stock AMC cam. They range from 256-266 degrees duration, like the Isky 256 (0.450 lift) and 262 Supercams (0.445 lift), and Comp 260H (0.447 lift -- 0.280 lobe lift).  Just a little less duration and lift than the Mexican 266 performance cam.  Isky makes a 270 duration/0.475 lift cam, but it's listed as needing higher compression and rear axle ratios than stock (9.5:1 w/3.70-4.11 gears and stock converter... could get by with less gear with a higher stall converter).  If that Mexican performance cam is readily availble it might be a good choice. It was made with the thinner air around Mexico City in mind though, so it might be a bit much for lower altitudes and probably requires a higher grade fuel (than 87 regular), at least at lower altitudes.
Frank Swygert
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.063 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or