Which synchronizer is best?

First time poster…just acquired my first e-type…running miserably. The two sparkplugs closest to the firewall are fowled…the others look fine. Is it safe to assume that the carbs are poorly tuned? I have the 4.2 litre with triple SU’s. I am looking into acquiring a synchronization tool. Which is better: the set up from British Tool Works, or the STE SK?

I find a peice of hose gets me close, then use any of the others for fine tuning.


Aways worked for me too without anything else.


Hi Kenn,

The 3 rod type kind of stink IMO. Measuring physical piston rise is indirect. Measuring actual flow is direct. The top one might work fine, but it depends whether the sealing plug is wide enough to cover the intake and shallow enough to not bottom out against the piston. I have the Synchron version of that tool. Not sure if made any more. The black rubber plug separates from that gray base and it fits fine in an HD8.


I have both the SK tool, and a UniSyn. I find the UniSyn easier to use with the 2" SUs as it fits the air horns better. The triple unit I have never tried, as like Erica, I am not bought into the premise of how they work.

And, FWIW, your carbs can be well synchronized, but still have mixture control issues.


I’ve always used a Unisyn with good results. For the mixture I follow the directions in the driver’s manual that describes listening to the exhaust. IMO it’s amazingly accurate.

One key point to remember is that the word “carburetor” is French which when literally translated means “Leave Me Alone”. Once you get them adjusted, walk away, hide your adjustment tools, don’t screw with them. You’re done. :rofl:


I have both the Unisyn and the Synchronometer, both work well enough. I also have the SU indicators that fit in place of the piston dampers, I’ve never found them useful.


I have the STE SK . Love it. Fast and simple. My Boss at the Jag shop has been using the hose for years and was skeptical but when he tried it he loved it and ordered one. Simple device,Instant and unambiguous response.

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Check the floats for sinking in that carb with the fouled plugs.

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+1 for the UNiSyn…

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And from me as well.

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Hello Kenn,
The SK Device that I have and all others I’ve seen work with the Stromberg Carburetor but not the SU equipped on the E Type, for the tapered rubber nozzle is too small in diameter to prevent the end of it interfering with the piston.

Using the SK device with the Stromberg Carburetors of an S3 E Type, the straight nozzle will work with all the carburetors except the left rear, unless you have the optional angled nozzle due to the heater box preventing a perpendicular approach to the carburetor face using the straight nozzle.

The UniSyn works for both Strombergs and HD8 SUs and fits into the tight restraint associated with the Left Rear carburetor of the S3.



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The effectiveness of the three dial gauge set up leaves me wondering though one of the acknowledged experts uses one - I’ve seen him do it The best carburettors can only ever approximate the correct a/f mixture for the conditions and use at any specific time, and trying for great precision is like saying a stopped clock is right twice a day. Yes, but so what? It’s no coincidence that modern computer controlled injection doubled gas mileage and power with it’s ability to have a/f correct at all throttle positions, RPM, and atmospheric conditions, when set up on a dynometer.

I have a pair of UniSyns and the German Synchron tool that Erica has (shown in eBay listing). I much prefer the Synchron. It’s actually better fitting to some HD8s than the UniSyn because individual air filters, if used need not have their backing plates removed. And there is no need to adjust the air flow like a UniSyn, The gauge has an absolute calibration that seems ideal for triple SUs, as well as for the dual carburetors fitted to Corvairs (which are usually tuned with UniSyns. Mine came with a pair of rubber pieces, to allow a choice of angles between gauge and carb.

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Some cheap plastic thing with a rubber mouth, hose, tiny orange tube with a white ball clips upright

Maybe a Gunson…anyway, it measures comparative airflow at each Carb mouth

They should all read the same airflow.

works perfectly, cost almost nothing

imo, should also remove pistons and measure Jet Depth from bridge with vernier tail

should be the same, record depths,

verify jet rises and falls when Jet screw is turned, the spring can rust or Jet be jammed

with the pistons out, afaic, if everything is perfect, one can peer down the Jet wells and see the fuel meniscus just below the top, should all be the same

its a good idea to make sure you return everything to baseline settings, even if you do not rectify problem, so I mark the screws with nail polish and record turns )ideally :smiley: )


I have two synchronizers

The one on the left came with the car and has the issue identified above by @angelw - getting it into place on the LR carb is blocked by the heater box

Within the last year I picked up the one on the right to sidestep that issue. I haven’t use it yet but expect it to work

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If I am taking pics later, I will post up one of m plastic el-cheapo

Not sure anything else can actually be better

Its only small, and I recently sprayed yellow paint on the black plastic, which I do with tools that can be hard to find

Anyone who wants my UniSyn can have it: I do just as well, and have for many dozens of years, with a piece of garden hose.


I never used anything else, in 20 plus years of running as E-Type, just a piece of small bore hose.

The secret of setting up the triple SUs is to follow the manual exactly, right from initially synchronizing the throttle stops with the linkage disconnected.

Assuming of course that timing, compression etc is all good.

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[quote=“Clive_Wilkinson, post:19, topic:445171”]
I never used anything else, in 20 plus years of running as E-Type, just a piece of small bore hose. [/quote]

Said the guys with calibrated tympanic membrane and temporal bone