MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Grose valves

I've had enough of one carb bowl regularly overflowing when first turning on the ignition (albeit it gets fixed by a carefully placed thump) so i'm fitting Grose valves. When fitting these in place of the traditional float bowl needle and seat, do you have to alter the height of the float lever fork (AUD2285)?
regards
Colin
C Manley

Colin - The only way to adjust the float lever height when using Gross jets is to shim the housing of the gross jet with small fiber washers under it. Not wishing to be the bearer of bad news, but the Gross jets being made to day are not very good. There has been many reports of them sticking closed, shutting off fuel flow to the float bowls completely. I you run into a problem with them and need to convert back to the tried and true needle valves, there is a fix for the problem you are experiencing. When enough fuel evaporates out of the float bowl, the float (and the lever) will drop far enough that the lever and the needle will form an angle that traps the needle such that it will jam the two together as the float tries to rise when fuel is being pumped in. The fix is to limit the drop of the lever so so that the needle never becomes trapped. For instructions on how to achieve this, see the article, Float Lever Drop on my web site at: http://homepages.donobi.net/sufuelpumps/ Cheers - Dave
David DuBois

Colin - I installed them in mine about a 1000 miles ago and have had no problem. I adjusted the float lever as instructed in the workshop manual.
Jeff Bennett

Colin - the PO of my car fitted them around 10 years ago - I have had the car 5 years and around 10k miles later have not had a problem ( touch wood)
Cam Cunningham

I've been running gross jets for about 20 years and 200,000 miles, and I've never touched them (other than to replace throttle shafts once). Good parts, as long as you keep the fuel clean. Some small bits or rust or dirt might make gross jets stick either open or closed, but it has never happened to me.
Barney Gaylord

I fitted Grose valves last year after suffering a quite regular sticking needle on one of the SU's for some time. Have to admit I did no re-adjustment whatsoever and just tried them out of the box. Worked perfectly, never had a problem since and the carburettor tune is unaffected. Very satisfied customer.
Bruce Mayo

Bruce,

Are those Grose valves on your Twin Cam engine?
Do you also have the "soft mounting" gaskets between your SU's and the manifold?


Mick
Mick Anderson

This thread was discussed between 23/06/2008 and 24/06/2008

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.