Synchrometer Recommendations, Your "secrets" on Carb Sync tools Options

[Martin Baker]

Well, after many years being away from Carbs, and learning Robert Bosch's systems on my own personnel vehicles, I am now taking what I learned about basic carb principles, to tuning Holleys for drag racing, and reading the two different books I bought on Webers, I would like to ask all of you kind folks what Carb Synchrometer is your personnel favorite? I see the Uni-Syn and another named Synchrometer TYPE SK from Redline Inc. The latter is much more exspensive than the uni-syn. An ex-F1 mechanic here in town says Uni-Syn. Are there others, and has anyone used this Redline product? Thanks.

[lapuwali]

FWIW, here's my sequence. It will be interesting to see how it's different from JP's. I'm assuming you're starting completely from scratch.

First, don't even start doing this until the valves are adjusted and the ignition timing is correct.

Start the engine and get it fully warmed up. Drive the car some.

Disconnect the linkage completely. Starting with one carb, loosen the locknuts on the air bypass screws, and turn them both in until they're lightly bottomed. Using the meter, turn out the lower reading of the two until it matches the one that's fully closed. The idea is to have the least amount of air possible going through the bypass. Repeat the procedure on the other carb. If you can't get them even front to back, then remove the bypass screws and make sure they're not all buggered up.

Using only one throat per carb (I usually use the rear ones), adjust the throttle stop screws until the carbs are matched to each other, and the engine is idling at your target speed (I shoot for around 900rpm).

Double check that all four throats read the same. If you have a mismatch front to back, go through the whole procedure again.

Reconnect the linkage, making sure it doesn't preload the throttles any. The engine speed should be the same after you reconnect it. Blip the throttle a couple of times, and check for sync again.

This gets the sync right at idle, and as long as there's not a big difference in the lengths and angles of the two sides of the linkage, they should stay in sync all the way to full throttle. It's hard to check sync much above idle, as the meter just pegs. Try to get the two linkage arms spaced the same distance apart from a vertical line drawn through the throttle spindle on each carb, or they'll open at different rates.