I have noticed inconsistencies in the specs for adjustment of key C2 Holley carb settings between the various sources of data. I am hoping that others have experienced this and might have some knowledge on which source is the "best" to use or other insight. My car is a 67 327 with 3810 type carb, but these inconsistencies apply to many models.
For performing a carb rebuild or adjustment sequence, you can refer to these sources, all of which I have:
1). Data sheet included with Holley rebuild kit.
2). Factory Chevy Service Manual (CSM) from the year of the car.
3). Holley official 4160/4150 technical service instruction guide (from Holley, my copy is from the early 70's).
4). Holley service and reference manual from third party publisher.
Here are some of the inconsistencies:
A). Dry float settings. For carbs without externally adjustable floats, the data for float settings differ between the rebuilt kit and the CSM. Also, the data sheet says to measure the setting from the "tip" of the float to the float bowl. The CSM doesn't specify where to measure from. The Holley manual specifically says to measure from the tip on the primary bowl only and the heal of the float on the secondary side. All of these would produce significantly different float levels depending on which you follow.
B). Secondary throttle stop adjustment. The data sheet with the rebuild kit and the Holley service manual both say to adjust the small screw the point where the secondary plates are completely closed, and then turn the screw in 1/4 turn after making contact. The CSM says turn in 1/2 turn after contact. On the car, this results in a significant difference in how the car idles.
Those are the major differences I have found, but I think there are others particularly in how the choke is set. Comments?
For performing a carb rebuild or adjustment sequence, you can refer to these sources, all of which I have:
1). Data sheet included with Holley rebuild kit.
2). Factory Chevy Service Manual (CSM) from the year of the car.
3). Holley official 4160/4150 technical service instruction guide (from Holley, my copy is from the early 70's).
4). Holley service and reference manual from third party publisher.
Here are some of the inconsistencies:
A). Dry float settings. For carbs without externally adjustable floats, the data for float settings differ between the rebuilt kit and the CSM. Also, the data sheet says to measure the setting from the "tip" of the float to the float bowl. The CSM doesn't specify where to measure from. The Holley manual specifically says to measure from the tip on the primary bowl only and the heal of the float on the secondary side. All of these would produce significantly different float levels depending on which you follow.
B). Secondary throttle stop adjustment. The data sheet with the rebuild kit and the Holley service manual both say to adjust the small screw the point where the secondary plates are completely closed, and then turn the screw in 1/4 turn after making contact. The CSM says turn in 1/2 turn after contact. On the car, this results in a significant difference in how the car idles.
Those are the major differences I have found, but I think there are others particularly in how the choke is set. Comments?
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