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MG TD TF 1500 - BALANCING tf CARBURETORS?

How does one balance carburetor fuel flow on the TF? I have borrowed a balancer from my carb rebuilder, but I can't use it with the front carb air filter in place and you can't remove the forward carb air filter with the carb in place. There must be another method??
Frank Bice

Frank - Try Moss P/N 386-300 as an alternate method of synchronizing the carbs. Cheers - Dave
D W DuBois

The old mechanic trick is to use a piece of garden hose as a stethoscope, one end placed at the carbie throat, the other end held to your ear.

With practice you can set the flow rates within pretty tight tolerances.
G Evans

In my experience of tuning twin SU's since 1983, the plastic tube (washer bottle size) in the ear is far more precise than anything you use over the carb throat. You are in fact interfering with the airflow by using anything other than the tube method.

By the way, you are balancing air flow here - not fuel flow. Make sure the link between the carbs is not connected when balancing the airflow.

The only way to balance the fuel flow is to ensure the fuel level in each jet is the same. Remove the dashpots, turn on the ignition & you should be able to see the fuel in the jet - they must be the same on both carbs - around 1/16" to 1/4" below the top of the jet. Do this before you balance the airflow.

Tony Slattery
The Classic Workshop
A L SLATTERY

Frank,
Sure you can remove the front filter. Remove the bolts on the backside of filter. The front bolt has poor access, but can be done with the right wrench.

Tom
'54 TF
T Norby

I believe Dave is referring to the angled pieces of stiff wire extend out of the top of the carbs that ride along with the piston,,, These work quite well,,,

SPW
Steve Wincze

Hi Steve,

Are you saying that when balanced both pistons should be at the same height? If this is so isn't it possible to check with a mirror? I set mine up with a manometer but did wonder about the height of the pistons viewed through the carb inlets.

Jan T
J Targosz

Jan,
Yes,, but it seems like Frank has a problem removing the filters,, therefore he can not look into the carb inlet...
SPW
Steve Wincze

Frank-- The front carb air filter is definitely a pain to remove. It is also a pain to re-install. After my engine was rebuilt I found it was not possible to remove the front filter though I could remove it before the rebuild. The engine shop was able to 'twist' the engine mounting slightly which gave me room to then remove the front filter as in the past. The problem with re-installation is lack of room to fit the bolts to the filter. I put a notch in the bolts so that a standard screwdriver would fit. Using a short screwdriver (maybe 5" in length) I then tape the front bolt to the screwdriver using masking or painters tape. This allows me to use the screwdriver to get the bolt started. I then remove the screwdriver/tape and use a wrench to finish the job. It also helps to loosen the forward carb overflow tube and rotate it out of the way (at least the way mine is positioned).

Larry
LD Kanaster

Thanks for all the input, gang. As it turns out, I have now reinstalled both carbs without the air filters, which will enable me to balance the carbs with a borrowed balancer before installing the filters. It appears to me that I can squeeze the front air filter into place by pulling the side panel out very slightly as I maneuver the assembled filter case into place. I should then be able to install the bolts from the back of the filter as suggested, tight quarters being a foregone conclusion. Installation of the rear filter is not an issue. Thanks again!
Frank Bice

One alternative and convenient way of checking the pistons synchronism at any engine speed (not just at idle) is by using the easy-to-fabricate tools shown in the attached picture (some sort of wires inserted in the piston damper rod and set level one to the other with the engine stopped). You do not need to remove filters for this test.

Jesús


J Benajes

Jesus,
I believe that is the method that Dave suggested and is part of the Moss Kit,,
Steve
Steve Wincze

This thread was discussed between 31/01/2015 and 04/02/2015

MG TD TF 1500 index

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