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MG MGA - Carb fine tuning

What would be the effect when using engine oil in the dampers instead of the correct light oil?

Also, I made my own tuning rods, see below, and find them invaluable.

BM Gannon


As I understand it, heavier oil gives slower throttle response, lighter or no oil give a quicker throttle response.

I have an SU tool kit that I bought in 1966 with a similarly useful pair of rods.

k v morton

Barry, I've use'd only the 'Unisyn' Vacuum tool. Your homemade rod tool looks easy to use and make-- can you give more details? Thanks, Bob Prentice
rsa prentice

I've never been impressed with the Unisyn. Moss still sells an SU kit that has the synchronizing rods, plus (I think) a jet centering tool and maybe a jet adjusting wrench. The synchronizing rods consist of a tube that fits in the top of each dashpot piston, and a couple of bent wires. Barry's rods are undoubtably less expensive and probably work just as well.

k v morton

I use 20 weight motor oil in my dashpots. Perhaps someone who races would be more sensitive to the effect of other oils, but for normal driving the 20 wieght works just fine.
Ed Bell

Thanks gents, I will syringe the heavy oil and replace.

Bob P, I first saw this device at Steve Gyles in UK and decided to make my own!

I cut two pieces of plastic tube, with a snug/tight fit into the dashpot, just long enough to protrude above the top (see photo above). Then I bent some (aluminium) wires to push firmly into the tubes. Start with the two wire ends together, as shown, rev the motor 1500/2000rpm and adjust until they rise and fall in unison. Set idle rpm and job's finished.
Hope this makes sense. Barry.
BM Gannon

Nice one Barry.

This is the SU tool kit that Barry saw when he was with me:

When I decided to do a rough and ready check the other day to ensure that I did not have a sticking piston, I just inserted a couple of screw drivers. But bent rods give the better accuracy.

Steve Gyles

Thanks Barry and Steve, I'll make mine as you describe. The 'instructions' on the website refused entry. If there are any special tricks, could you let me know? Thanks, Bob P.
rsa prentice

Hi Bob,

The instructions dowloaded OK for me.
I have placed them at:

It is a PDF file. You need the Adobe Acrobat Reader program to read it. This program is free of charge, but very large, at:

If you prefer I could convert the PDF file to image files and upload them here.

M F Anderson

Mick, Got it , Thanks, Bob P.
rsa prentice

This thread was discussed between 05/02/2009 and 09/02/2009

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