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MG MGB Technical - what is the right needle

I have a rebuilt motor with the following 8:8 pistons, Aluminum head, peco header, K&N deep filters with short stub stack inside, Hif4 carbs with solid butterflies,delta 270 cam. I am looking for needle suggestions as it smells rich at idle although the plugs look to be running light brown.
bs stone

AAA is the usual starting point for tuned B series, and they work fine in my car. There are some needle choice programs around, I've got Haystack on a machine here and it was a big help.
Stan Best

BS. Basically if the plugs are a light brown colour after a good run then all is fine. It's not so important that it is a bit rich at idle as these cars tend not to be 'idle' very often!

Cheers

Tony
Tony Oliver

bs The needle has little or no effect on the mixture at idle. Idle is adjusted with the mixture screw and the Number one station on the needle is the same on most needles (not all but most). Denis
Denis4

Spot on Denis but it also needs to be said that if the car has the correct needles the idle mixture will effect the mixture right through the range. For example if the needles are correct and idle mix. is correct it will be fine but say if the needles are correct but idle is set rich it will be rich everywhere. Therefore I'm afraid I don't agree with T. about it doesn't matter if the idle mixture is out. Gas analyser is the answer. Cheers Willy
WilliamRevit

This thread was discussed between 24/03/2009 and 25/03/2009

MG MGB Technical index

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