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MG MGB Technical - HS6 jets

I was looking at HS6 jets in the Moss online catalogue today. The MGC HS6 jets are a different part number than the Healey BJ7 HS6 jets. I'm assuming they are different diameters, but the sizes are not listed. I believe I'm looking for something in the 0.100" variety. Does anyone know exactly which jets are in order as it pertains to the MGB application? As I look at the jets I have now it appears one is slightly larger, this could be either from wear or more likely mismatched parts. I was not the one who rebuilt the carbs previously- in fact the carb bodies are mismatched themselves, so I'm evening the field by re-bushing the throttle shafts and re-jetting. Using SY needles which are in fine shape. Any help would be appreciated.

Mark
Mark J Michalak

Normally the HS6 runs 0.100 jets, as you know there are a large number of needles available. I believe Moss or VB sells a duel HS6 setup for B's. You may want to ask them what needles and jets are used in their setup.
John H

Just buy new jest for the MGC - they should work fine.

The healey and the MGC will all be .100 so I'm not sure why they carry different part numbers, but then the factory used to do that as well sometimes.

The SY is a good staring point for that carb on an MGB engine. If the engine is stock they will be too rich, but then if the engine were stock, it would be a waste of time fitting HS6 carbs, so I expect you have a tuned engine?
Bill Spohn

Mark-Although all of the HS6 jets are .100" dia. there are some differences. To make a long story short, since not all carbs are mounted horizontally, it necessary to rotate the float chambers so that the tops are level. This varies on the various marques that use SU carbs. MGBs' are 20 deg, MGC&AH are horizontal, Volvo is 30 deg. The plastic tubes that connect the jet to the float chamber has to be longer as the angle increases. Also, there might be a slight difference on the choke lever mounting points. The plastic jet heads are coded red for horizontal applications and black for the others. As long as the tube can be connected to the float chamber with out stretching and the choke functions properply, they shoud be interchangable.
Sorry to hijack your list.
Berry Price
BTP Price

Thanks guys, that's what I needed. I'll go for the MGC jets.

Bill, my engine is .030" over with 9.5:1 pistons and the HS6 performs nicely even without a modified cam, contrary to what you might hear. The SY needles seem to tune in nicely, though I do have a noticeable air leak around the throttle shafts, so I might need to switch needles once that's fixed. I plan to build a ported and polished big valve head to take advantage of the tweaked bottom end and big carbs.

Mark
Mark J Michalak

Mark,
Burlen (who make the SU stuff here in the UK) catalogue says that MGB HS6s use AUD9148 and AUD9149. MGC is different.
N
Neil22

This thread was discussed between 04/06/2008 and 05/06/2008

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