VotW – Dual S.U. Carburetor Tuning

November 9, 2016 Staff Video of the Week, Articles, Highlights, Restoration & Repair 2

For our Video of the Week this go round I want to go back to something that gives folks a lot of headaches –VotW - Dual S.U. Carburetor Tuning tuning a dual S.U. carburetor setup. We are also going back to an old friend for this, John Twist of University Motors. While this video specifically addresses the HIF4 carbs of the MGB, the same basic principals of tuning and balancing apply to all dual SU setups. We covered the basic theory and operation of the S.U. side drafts in the past, but this video is more specific to their actual tuning.

[Corrected, see below] By the way, do you know what the “I” in the “HIF” stands for?  It means “integrated”, as in the float bowl is in-line with the carburetor itself, in this case directly under it. If the float bowl is to the side of the body, then it is an HSF carb. Oh, and that number “4” refers to the throat size. That number is translated as each 1 is a 1/8 inch, staring at one inch. So an HIF has a 1-inch throat. An HIF4 would have an inch and a half throat. Pretty simple once you know.

I may not be in the majority here, but I am quite fond of S.U. carburetors. I find the easy to understand, easy to work on and repair, and fairly robust. Once you understand the basic principals and tuning methodology, you can get them to perform quite well. Plus, unlike say a computer controlled fuel injection system, you can make quick and dirty temporary repairs on the side of the road when you need to limp home. Plus, they will operate even when in a pretty sorry state of repair. Oh, and when polished up, I find a dual S.U. setup quite attractive.

Anyway, hope you enjoy the video … and then go out and get your hands dirty!

Staff

Related Articles

Burlen Celebrates Record-Breaking Year
Corporate Business

Burlen Ltd Celebrates Record Breaking Year and Plans Expansion

March 2, 2017 Staff Corporate Business, Highlights Comments Off on Burlen Ltd Celebrates Record Breaking Year and Plans Expansion

Burlen Ltd, the world’s only manufacturer of genuine SU (Skinners Union), AMAL and Zenith carburetors, fuel pumps and spares, is celebrating a record-breaking 2016 and continuing to demonstrate remarkable growth. The Salisbury-based company enjoyed a hugely impressive annual turnover of £5.2 million in 2016 – smashing its previous best records and its own start-of-year target in the process. Burlen has an incredibly rich history with products dating back over one hundred years and a stellar reputation to uphold, which is of the utmost importance to the Burnett brothers. Staff

Bill Toops watercolour painting of Burlen Services in Greencroft, Salisbury where it all began in 1971
Highlights

Burlen Ltd Set to Launch Innovative Fuel System in 2017

December 22, 2016 Staff Highlights, Classic Cars 7

Burlen Ltd, the world’s only manufacturer of genuine SU (Skinner’s Union), AMAL and Zenith carburetors, is gearing up for an exciting 2017, with an innovative and truly ground-breaking product set to roll out of the workshop. This game-changing launch from Burlen will be an all-new and complete fuelling system that includes a fuel injection device working inside an SU carburetor, and it’s set to completely shake up the market when it’s released in the summer. Staff

SU - Skinner's Union Book
Highlights

S.U. History – Skinner’s Union Book

November 10, 2016 Staff Highlights, Corporate Business, Library, People Comments Off on S.U. History – Skinner’s Union Book

Congratulations to Mike Harvey who has been awarded the Pre-War Car Michael Sedgwick Award 2016 for his publication ‘Skinners Union – A History of the skinner family and S.U Company‘. The award, that takes the form of a plaque and £250 given by the Michael Sedgwick Memorial Trust, hopes to ‘encourage new research into motoring history and to make the finding available to the public’. The winner has to demonstrate excellence in research, presentation, readability and novelty, that will materially further our understanding of the subject. A short list of nominated books were assessed by a panel of judges, who are themselves respected authors and highly knowledgeable enthusiasts. The panel was headed by chairman Guy Loveridge, motoring author and broadcaster and Deputy Chairman of the Guild of Motoring Writers. ‘Skinner’s Union – A history of the Skinner family and the […]

2 Comments

  1. Check the HIF definition, please. I believe it’s Horizontal Integrated Floatbowl.
    And sizes are increments of 1/8 inch, beginning at one inch. H is a one inch, H2 is a 1.25 inch (MG TD); H4 is 1.50 inch, (TD MkII, TF, MGA, MGB).

    • You are very right! I was writing quickly and got my measurements wrong. My carelessness stands corrected, thank you for catching it.

Comments are closed.