synchrometer question

[robphelan]

background:
2.0l w/ dual weber 44IDFs

I am trying to synchronize the carbs and noticed that both barrels on Carb A are reading the same, while both barrels on Carb B are reading reading the same.

However, the readings on Carb A compared to Carb B are more than a tad different.

Any help on what this is indicating?

thanks,
robster.

[SGB]

Thats what ya gotta synchronize! Does the linkage have a drop rod with little ball sockets on each end connecting the throttle on the carbs to a crossbar between the two carbs? The idea is to change the length of the little drop rod between the ball jionts on the "high draw" carb to reduce it's vacuum to be equal to the other one. You may have to increase on side and decrease the other. On my car with 40 IDFs, the rod has to be shortened to reduce the opening of the carb. One side of the drop rods is often reverse threaded, so one could theoretically lossen both lock nuts and turn the drop rod to raise or lower the amount of travel before the butterflies open. That is an OK way to get close. On my car, I can only get a close balance if I take the drop rod off the carb and cross bar and adjust it in tiny tiny tiny increments- on the car, test it, off the car, adjust it, on the car- test it, off the car- etc.

[robphelan]

whew! i was afraid this was more of a compression (lack thereof) indication.

So, if I need to reduce the vacuum on 'high draw' carb(which reads ~21) and/or increase the vac on the 'low draw' carb(reads ~11), is there a general measurement that they should both be close to? such as ~16, or so?

[maf 914]

The numerical reading on the synchronizer is not really important. It provides a relative reading from throat to throat. Since the left two throats read the same and the right two also you're in good shape to start.

Disconnect the linkage and set the throttle screws to equalize both sides. Do this at your target idle speed.

Now reconnect the linkage and check again. They should both still flow the same. If not, the linkage is opening one of the carbs. Which carb is drawing more air? It's being pulled open off the throttle stop. Shorten or lengthen the linkage arm on that carb to allow it to return to the stop. You can usually see this at the stop.

Good luck.

Mike

[robphelan]

thanks for the help... going to try to get to it as soon as i get home - if I clear it with the wife, of course.