[Mg-t] Initial jet height

[Jim]

This has to be the best instructions for tuning SU's here than any ever printed in the service manuals
Well done Lawrie...

Sent from my iPad

> On Apr 27, 2017, at 4:49 PM, lawrie <lawrie at britcars.com> wrote:
> 
> Rick,
> 
> The initial setting for SU H-series carbs is always 6 flats down. Having them set to within a thousandth or two is overkill! Once the engine is up to temperature, and you are sure the ignition timing is set perfectly (32 degrees b.t.d.c. at 3,000 rpm), then you make sure each  carb is sucking the same amount of air (the interconnecting bar at this time should be loose enough for each throttle to be opened individually) and the link connecting the two jet levers is disconnected. Then you adjust each carburetor in one-flat increments up or down until you achieve the fastest, smoothest idle, set your idle speed to 850 or 900, making sure the airflow is still synchronized when you are done. It is highly unlikely that when you have achieved this perfect idle both jets will be the same number of flats down; they do not have to be!
> 
> Then tighten the clamp on the interconnecting bar so both throttles open together and the airflow is still the same. Finally, adjust the length of the rod between the jet levers so the pins push through without moving the position of the levers.
> 
> Lawrie
> 
>> -------Original Message-------
>> From: Richard Lindsay <richardolindsay at gmail.com>
>> To: mg-t at autox.team.net
>> Subject: [Mg-t] Initial jet height
>> Sent: 27 Apr '17 12:53
>> 
>> Hi Friends,
>> 
>> Just got the SU carbs assembled and back on my '53 TD. I preset the
>> jet heights 9 'flats' down from flush. I then measured the distance
>> from the jet top to the jet carrier in the bridge. One carb measured
>> 0.072", the other was different by a few thousandths. I set both to
>> 0.072".
>> 
>> You? What jet height do you eventually decide upon for a healthy
>> engine? Thanks.
>> 
>> -rick, in Houston
>> PS: I just bought a TR6 project. :-o
>> -------------------------
>> ______________________________________________
>> 
>> Mg-t at autox.team.net
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation $11.47
>> Archive: http://www.team.net/archive
>> Forums: http://www.team.net/forums
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/mg-t/lawrie@britcars.com
> ______________________________________________
> 
> Mg-t at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $11.47
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/mg-t/mgjim55@pacbell.net
>