Carb Synchronizer suggestions.

[YellowLakeWelding]

Okay I'm buying a new Synchronizer how ever I have three options...a mercury style, gauge style and a digital style of tester...now which of these is the most durable, easy to use, reliable and especially the most accurate? The digital one scares me for many reasons especially the accuracy and reliability.

 

[Super Cholo]

The most accurate would be a u-type mercury style. The others are sensor dependent indicators. But, it probably does'nt make much difference. In my carb syncro experience, the relative DIFFERENCE was the important factor. John--Las Vegas.

 

[sammon287]

For synchronizing carbs on what? I have a Morgan Carb-tune II that is made in England and is not mercury, dial gauge, or electronic. It uses calibrated stainless steel rods in the glass tubes. I use it on 4 cylinder motorcycles. It was reasonably priced including shipping from the UK.

 

[knobby]

Mercury is the way to go but keep those revs down.

 

[daveroy]

For synchronizing carbs on what? I have a Morgan Carb-tune II that is made in England and is not mercury, dial gauge, or electronic. It uses calibrated stainless steel rods in the glass tubes. I use it on 4 cylinder motorcycles. It was reasonably priced including shipping from the UK.

I'll second the Carb-TuneII I have a four bank set and they work great!
(bought mine here in the states somewhere, but its been soo long I can't remember where)

 

[diggerrick]

What is it for? Just because you have multiple carbs doesn't necessarily mean you need to synch them - it's usually only required on an individual runner manifold.

What Hilborn recommends:

http://www.hilborninjection.com/product.asp?Id=438&CatId=231

 

[obsessive]

Here are 2 threads on the subject with a lot of information:
http://venturerider.org/forum/showthread.php?t=34596
http://venturerider.org/forum/showthread.php?t=34494

The summary:

The mercury style is the most accurate and requires no calibration, but contains mercury which can be nasty stuff if not handled properly. The gauges are also long and should be stored vertically.

Emgo-style vacuum dial guages are next on the accuracy scale, as they can be easily calibrated. Most come with a 1-to-4 splitter for instant calibration check, and have proven not to drift across the vacuum range in relation to each other over time. Simple storage with no liquids to worry about.

The Morgan carbtune loses calibration over time and cannot be calibrated. This is its major shortcoming. It is also prone to the steel rods eventually sticking a bit in the tubes. These issues are well documented by frustrated Morgan carbtune owners in many forums. Don't bash me for bringing them to light here please.

The Motion Pro SyncPro is the bottom of the pile. It is advertised to work the same way as a mercury set, but does not. This thread is a great read: http://www.venturerider.org/forum/showthread.php?t=38904

Of the four styles, I would recommend one of the first 2 styles, based on your comfort with mercury. The only one completely NOT recommended would be the Motion Pro.

 

[amorrow]

What is it for? Just because you have multiple carbs doesn't necessarily mean you need to synch them - it's usually only required on an individual runner manifold.

What Hilborn recommends:

http://www.hilborninjection.com/product.asp?Id=438&CatId=231

I use that style on my Mustang with individual-runner manifold and Weber 48 IDA carburetors, and it was effective in setting the idle and getting me started in improving driveability. For an individual runner automotive setup, I'd recommend that style syncrometer...very easy to use.

 

[35mastr]

Subscribed

 

[A_Pmech]

All I've ever used is a comparative oil manometer. Fancy term for a few lengths of 1/8" plastic tubing filled with colored oil and taped to a broom handle. For a twin, using this type of setup is very easy. Hook one end of the manometer to cyl1, hook the other end of the manometer to cyl2. When the column of oil in the tube is balanced, you're in synch. On a four cylinder engine it takes three manometers. They're hooked up to 1 and 2, 2 and 3, 3 and 4. When they all balance the carbs are in synch.

1" of Mercury = 15.77" of Type F ATF. Thus, an oil manometer is almost 16 times more precise than a mercury manometer. With that level of precision it is easy to chase one's tail if not practiced.

 

[digdug18]

funny, the people I know that sync the SU carbs on english motors use a length of rubber tubing to hear the carb, and sync it that way. Seems to have worked rather well for the last 50 years or so.

 

[Vicegrip]

I use that style on my Mustang with individual-runner manifold and Weber 48 IDA carburetors, and it was effective in setting the idle and getting me started in improving driveability. For an individual runner automotive setup, I'd recommend that style syncrometer...very easy to use.

works great on Porsche motors with 2 or 3 barrel carbs too. I have a set of 2 that I checked and read the same. I also have a 4 tube/fluid rig I used for years on motorcycles prior to getting this setup. I found that the gray plastic units work as well unless the carb arrangement precludes them fitting. Less setup and tubes flopping around getting kinked in the tool box drawer.

 

[cglasgow]

Since the OP hasn't told us what he's working on, I'll throw in my favorite for synching SUs -- the SU Toolkit, Item B, here:
http://mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=31163
(Not trying to pimp Moss but they had the easiest picture to find. Other vendors sell them.)

Put the two tubes into the dashpot pistons, put the two wires into the tubes, align the wires, then start the engine. Adjust the throttle stops until the wires are aligned at idle and voila! Carbs are synched. They also allow you to see easily when you've lifted the pistons 1/32" to check the mixture, just like the book says. Finally, they allow you to verify the synch throughout the entire rev range, and to watch to make sure that the pistons rise at the same rate. The kit also includes references for setting float drop, a jet adjusting wrench, and a jet centering tool.

Of course they're useless for carbs other than SUs, again, the OP didn't say.... ;-)

 

[YellowLakeWelding]

Sorry been busy, haven't been on here. I'm using it to sync out-boards, mc's, atv's, etc... I've got several customers making appointments for boats so I need to get one soon. After reading all the responses here I think I'll go for a mercury sync and a guage sync also since the one I looked at was only $100 with adapters and a hard case.

 

[Bruce M]

I use the "snail" style single unit pictured above. Sold by weber/dellorto too. Easy and quick to move around the different inlets.

Prior to that I used the rev counter........

With a good rev counter (not digital), you can remove each HT lead in turn from the distributor (use gloves) and check how much the revs drop on the rev counter (write it down). The revs that drop the most are pushing the hardest so reduce that barrel. Once the idle has been set, it will probably be a little high (so it doesn't stall when you remove a HT lead) so carefully reduce all the idle screws by the same amount. Once the idle stops are correct, crack open the linkage slightly (lock it off somehow) and repeat the process to set up the linkage properly.

A bit more work and fiddly but much better than the nasty cheap sync gauges.

 

[KraftwerkMk1Jetta]

This is a great thread. I have an old Triumph Bonneville i'd like to get a carb synchronizer for.

 

[toolman1967]

I have used the gauge style for years and have done everything from 2 Cyl Motorcycles to Jag 12 Cyl motors. Never had a problem and they are dead simple.

 

[KraftwerkMk1Jetta]

I have used the gauge style for years and have done everything from 2 Cyl Motorcycles to Jag 12 Cyl motors. Never had a problem and they are dead simple.

what is a good brand of gauge style?

 

[mtkst19]

i use a uni-syn.

cant say i have used any other style but i have used this on mutli carb setups like porsche 6 and jag v12. it works for me so no need to try something else.

 

[mtkst19]

All I've ever used is a comparative oil manometer. Fancy term for a few lengths of 1/8" plastic tubing filled with colored oil and taped to a broom handle. For a twin, using this type of setup is very easy. Hook one end of the manometer to cyl1, hook the other end of the manometer to cyl2. When the column of oil in the tube is balanced, you're in synch. On a four cylinder engine it takes three manometers. They're hooked up to 1 and 2, 2 and 3, 3 and 4. When they all balance the carbs are in synch.

1" of Mercury = 15.77" of Type F ATF. Thus, an oil manometer is almost 16 times more precise than a mercury manometer. With that level of precision it is easy to chase one's tail if not practiced.

i never used this style but way i picture it in my head it is stupid easy that i am going to try it on my next setup. basically the vacuum draw from each carb will "pull" the fluid toward the carb. when you have each side balanced-- then the level should be the same on the stick.

so example-- say i have a 2 foot ruler. run the clear tubing around the 2 foot ruler. then fill w/ fluid. hook each line up to the separate carbs and start. adjust until they are both on the same spot of the ruler.

is this correct?