Webers and the Morgan Carbtune II

[stuartgb100]

Has anyone been using this little bit of kit to balance their Webers, and if so, with what success?

I've a couple of questions for anyone who's positive about its' merits.

Here's a link to the Morgan website:

http://www.carbtune.com/carbdtls.html

Regards,
Stuart.

[bill308]

Hi Stuart,

I use a bank of 4-mercury manometers to synch my carbs. In my opinion, this is the only way to do it properly.

The carb tune device shown is their replacement for the mercury type. It uses stainless steel slugs in a tapered tube to perform much the same function as the mercury types. I haven't tried one, but it's probably almost as good, if manufacturing tolerances are tight enough. With mercury, tolerances just aren't critical, it's the height of the column that counts. The carb tune shown is safer as there is no danger of spilling mercury.

To use, you still need to tap into the intake manifold with a fitting if you have Webers. Some Dellortos will accept a fitting in the top housing that leads to an orifice down stream of the throttle plate. I currently have Webers so I tapped the under side of the intake runners to accept a hose barb. My friend Tim tapped the top side of the runners on his S3. When not used for balancing, I merely connect adjacent barbs together with a length of tubing to seal the openings. The tubing is small enough that there is little to no cross flow, at least no enough to make any difference in balance. Alternately, the barbs can be removed and a plug substituted.

If you decide to purchase a carb tune, let us know how it works for you. Or if some one else has tried one I'd be interrested on their feedback too.

I hope this helps.

Bill

[alaric]

Hi. I've got one of these devices. It fitted very easily into existing threaded holes in the carb barrels on the vacuum side of the butterflies. Fitting does not interfere with the running of the carbs. I bought it because I could not get the engine to run smoothly. It took a few seconds to balance the carbs up once it was fitted, and the engine ran really nicely from then on; once balanced, I could set the mixtures to within a quarter of a turn by listening to the engine tick over.

Sean.

[cliveyboy]

I have a carbtune and think they are great.
Big advantages being you plug straight into the carbs via a couple of tapped holes and do not need to remove the airbox. Takes under 2 minutes to set it up.
The other advantage is that you balance the carbs as a complete system with air box and air filter attached so you can compensate for any variations in flow to each chamber caused by the air box etc

Cliveyboy

[stuartgb100]

I know that Dellortos already have a tapped outlet to connect the Carbtune to (the depression blanking screws), but what about 40 DCOE's?

Or would I have to drill the manifold?

The earlier posts seem a little ambiguous!

Regards,
Stuart.

[ianf]

Stuart,

My 40's have little white caps on the engine side of the barrells which when I last had someone balance the carbs were removed (pulled or screwed off??) to push the manometer tubes on.

Ian

[types26/36]

Ian,
If you are describing 4 white plastic plugs (when removed there is a screw with a locknut, usually sealed with paint) this is not for connection for a manometer, it is an adjusting screw to balance the air flow between chokes. It is only on the later carbs and is set by the manufacturer and "supposed" not to be tampered with in service although it IS sometimes nessesary.
If you take out the screw you will find it is tapered to a fine point.
Maybe you have something different if so I have not seen them so a picture would be nice.

[bill308]

The other advantages of a system like this is that your hands are free to tune and slight air leaks like through the throttle shaft bearings are automatically compensated for.

A third advantage is that off idle balance, say up to 2000 rpm, can be easily checked. Often times, balance at idle can be good but as soon as you go above idle, balance suffers. In practice, I always adjust off idle balance first. Once this is ok, then I adjust idle balance with the with the idle stop screws and air bypass screws (as with the later Webers and Dellortos) if you have them.

One thing to check if you have Webers, is that the outside barrels are spring loaded. This can twist the brass throttle shaft a little over time. A multi bank system will pick this up. I do not subscribe to the practice of drilling holes in the throttle plate to rectify the resulting imbalance. I believe one should either replace the throttle shaft or twist the throttle shaft back to where it should be. Unfortunately, this practice is not easy to do.

Bill

[elangtv2000]

I use a bank of 4-mercury manometers to synch my carbs. In my opinion, this is the only way to do it properly.



Bill

Hello all,
I am a new member of this forum, and a new owner of an Elan. I have a fair amount of experience balancing betwen carbs, but what methods are used for balancing between barrels? I have seen a flow bench in action, but one information source indicates drilling small holes in one or the other throttle plates, while another discusses removing small amounts of metal at the progression holes. Anyone experienced with balancing between barrels?

Thanks,
Greg

[types26/36]

[
what methods are used for balancing between barrels? I have seen a flow bench in action, but one information source indicates drilling small holes in one or the other throttle plates, while another discusses removing small amounts of metal at the progression holes. Anyone experienced with balancing between barrels?Greg

As Bill mentions twisting the throttle shaft (tried it but not much sucess)
Drilling holes in the throttle valve (dont fancy that)
Dont know about removing metal from progression hole??? (dont fancy that anyway)
Also as Bill mentions on the later carbs there is a by-pass system, these are the screws I mentioned covered by the plastic plugs (weber) see the pics.

[ianf]

Brian,

Your pic describes the plugs I was talking about. I will pay my man a visit to see where he attached the manometer (it was a few years ago). I have set up since by ear and engine running - probably miles out but the car goes ok.

Ian