Sync-Pro Carb Synchronizing Tool v ABN Carburetor Synchronizing Gauges
Sync-Pro
The first thing I will say might save you some reading. JUST BUY A VACUUM GAUGE. It will be less expensive to buy, more durable, not require fluid refills or frequent calibration and it will just be much easier to use. Most importantly, a vacuum gauge will tell you the exact value of vacuum in cmHg which is necessary to know if you want to determine if the vacuum is in spec as well as balanced. The Sync-Pro only compares the vacuum produced by each engine cylinder; it does not show the value of vacuum. The long fluid columns of the Sync-Pro are great for precise reading but I doubt anyone would have serious objection to using a vacuum gauge sync tool with four large faces and needle gauges. BUT— if you still want to buy a Sync-Pro for some reason, here’s the details.
The Sync-Pro instructions for assembly, calibration and fluid refill are well written and illustrated. Follow those and you can’t go wrong. Steel screws hold the body of the tool together and they tend to vibrate out when the engine runs so make sure you tighten them. Just don’t tighten them a lot or the body might crack.
The tool is well made considering it is mostly made of plastic. The essential parts of the Sync-Pro are the valves and reservoirs and they are of high quality materials and construction. The steel valves with o-rings are cleanly tooled and they fit precisely in the reservoirs which are cut (not molded) into a solid block of plastic. The brass restrictors that fit in the vacuum hoses also are well made and function flawlessly.
The Sync-Pro I purchased came with only a few drops of fluid in each reservoir so I suggest buying a refill bottle of the Sync-Pro manometer fluid. One bottle will probably be enough for about two complete refills of all four reservoirs. The Sync-Pro fluid is an ethyl glycol / water solution. I’ve read that ethyl glycol antifreeze mixed with water will work just as good but I have not tried it.
The fluid is the only part of the Sync-Pro that does not work well. Engine vibration seems to cause the water in the fluid to separate from the ethyl glycol. The water portion sticks in the fluid tubes when the engine is shut off. The resulting water droplets remain stuck in the fluid tubes which causes air gaps in the column when the engine is turned back on (and you will be turning off and on with the 14 when you use this tool). The air gaps throw the calibration of the tool way off. The only good way to clear the water droplets to the reservoirs is to disconnect the vacuum hoses and and wave the Sync-Pro down like you would a thermometer. Then reconnect the vacuum hoses and resume. The tool is accurate and easy to read as long as the engine is running and there were no air gaps in the fluid columns before it was turned on.
Check out my Sync-Pro How-To for more details and pics.
ABN Synchronizing Gauges
What can I say, it’s everything the SyncPro is not. The ABN is easy to use, Requires no assembly, is relatively inexpensive (Amazon—$70) and it indicates vacuum in cmHg. Mine appears to be very accurate. All I needed to do was zero one of the gauges and all indicated the same reading as the vacuum applied to them with my mightyvac vacuum pump. That is not as perfect as an expensive test gauge but since the results were so consistent, I trust the gauges are accurate enough. The dials are large and easy to read. The damper valves for eliminating needle flutter work great (I needed to adjust one of those). I can’t say much more, it just works. I tested it against the engine vacuum sync done with my SyncPro and the ABN’s gauges all indicated as they should, that all throttle bodies had even vacuum.
There are one two other vacuum gauges available online for under $100 and I’m will bet they are very similar to the ABN gauges. There is a very beautiful chrome set for a little extra $$ but the dial does not have small enough increments for precise reading and it’s not calibrated with metric units.
Using the ABN is easy but I have included a tutorial along with the SyncPro.
