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MG MGB Technical - tuning Moss supercharger on a 1972 MG B GT

Hello,
I fit a Moss supercharger kit on my MG B GT 1972, which have a normal compression motor.
But I find the motor is not powerful, I doesn't succeed to start with the choke, and I must depress the accelerator pedal to start the motor. The motor seems to be less powerfull than before and it turn not smooth, but on three or two cylinders at beginning and it must be hot very hot to turn normally. I thought it was the time advance, but when turning the distributor, it has no effect. I don't know how to tune-up this supercharger...
Can you help me?

Christian
Christian Delaval

C- See my comment on "General MGB". Vic
vem myers

Christian,

I would STRONGLY suggest that you look at the following link and then contact Ray. His web site has LOTS of technical information concerning tuning his supercharger. Plus Ray is a VERY nice person and will help you.

http://www.treasureislandjewelers.com/1977mgbSupercharger.htm

Robert
Robert Browning

what is AFR test? the advance must be 5 ° before, isn't it? how to tune carb mixture? I didn't modify valves, you think I must change valve clearance? before the advance was 13 ) before. I didn't change it before start the motor and after I tried to change manually, but without better result. Before mount SC, the motor was great, a super good compression and very good combustion because I put a ignitor with hall effect. I fit the SC in following the guide, and when I started the motor it start but not with the choke, but with accelerator. the motor run but very rough, on 2 or 3 cylinders at cold and after run normally but not very powerful. When I depress the throttle pedal, I hear a big "shuffle", but the motor is not power, very powerless than before....
Perhaps the serpentine belt is not enough tied? But I doesn't think.
Can you tell me to tune the carb mixture?
But it is not normal that the ignition is bad, because before it was very good....
Christian Delaval

Hello everybody,
I'm very happy because my supercharged Mg b Gt run good. Effectively, the problems of bad power and misfire was due to bad mount of supercharger manifold and leak with gasket. I made up some stepped washers to deal with the different thicknesses between the inlet and exhaust manifolds and after I started up the motor and.....nothing, just an explosion on one cylinders.....I changed the distributor, verify the advance timing, the carburetor, all was good. Finally, I put the old spark plugs and oh happiness, the motor started well and I made test on road, all is good. It is vey special that the spark plugs of the kit were not good.

Christian
Christian Delaval

Glad to hear you have sorted it Christian. I have a Moss kit on the shelf awaiting time to fit. The chap I bought it from (he was going down the engine transplant route) included some stepped washers, so I guess they are required - as are working spark plugs!

Iain
67 BGT
I D Cameron

hello,
my MG b GT runs well, but the motor is too warm, and I think it comes from the spark plugs who are hot spark plugs and not these furnished in the Moss kit.
I think I did'nt start engine with these spark plugs because they were to wet wth a lot of started not succeeded. This evening, I remove old spark plugs and fit the new.

Christian
Christian Delaval

This thread was discussed between 02/06/2007 and 11/06/2007

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