fomoco_44 Posted May 30, 2009 Share Posted May 30, 2009 Hi All(again) Been fiddling with the carbs on an engine that I bought from a wrecker. After a bit of research I believe that they are HS6 SU's off a Volvo, and not the 240z SU's. To get it to idle ok I have to wind the mixture nut on the front carby right down(nearly 5 turns), while the rear is about what I've read it should be(2 1/2)...even then the front carb is still running a bit lean. Have looked for vacuum leaks using the typical methods, and can't seem to find any. When I isolate the carbs from eachother, via blanking off the balance pipe, I notice that the front has a higher vacuum than the rear I've got one of the good sync meters, and have set them both equal. I have also done the test where you lift each piston seperately to check the others mixture....and got them both to the point where they almost stall, then I richen them up a notch. To my way of thinking, the only thing left is the needles(mis-match or bent). Does anyone know what type of needles are a good match for this engine\carb combo?...also, where I can get replacement needles? P.S. I have also checked the valve clearences and cam timing Quote Link to comment Share on other sites More sharing options...
C.A.R. Posted May 30, 2009 Share Posted May 30, 2009 I got my new needles from here: Wilson Carburettor Service 110 Queensberry St, Carlton, VIC 3053 p: (03) 93473036 Quote Link to comment Share on other sites More sharing options...
fomoco_44 Posted May 30, 2009 Author Share Posted May 30, 2009 Hi again Lurch, What type of needles did you get? I'm used to webers....so the whole needle id has me stumped. I understand that the shape\taper controls the mixture throughout the range.....just not sure which one to start with. Quote Link to comment Share on other sites More sharing options...
C.A.R. Posted May 30, 2009 Share Posted May 30, 2009 I can't for the life of me remember what they were stamped as... Give them a call - they gave me a recommendation of what needle to use. Quote Link to comment Share on other sites More sharing options...
chris240 Posted May 30, 2009 Share Posted May 30, 2009 It looks like you grabbed yourself some late model SU's being the series 6...much superior in my opinion to 240z Hitachis and 260z flat-tops. good buy. Quote Link to comment Share on other sites More sharing options...
fomoco_44 Posted May 31, 2009 Author Share Posted May 31, 2009 Thanks Chris Gradually getting my head around them Quote Link to comment Share on other sites More sharing options...
fomoco_44 Posted May 31, 2009 Author Share Posted May 31, 2009 Just pulled the needles out, looks like they are BAX type. ANyone have any thoughts on these Quote Link to comment Share on other sites More sharing options...
ChrisZ Posted June 3, 2009 Share Posted June 3, 2009 Are you sure the float high is right on the front carb, it sounds to low to me, are yo looking for SU needles or Hitachi ?, here is a link to a SU needle chart http://www.teglerizer.com/cgi-bin/needle100db.cgi?Needlecode= but it won't do you any good. If you have a bend needle, you can straighten it out its not that hard, take the needle out of the dome piston, put it in a cordless drill or another drill machine, while you let it spin, you just touch it with a piece of soft wood, by pushing the wood a little harder, you will slowly straighten it, you will not be in doubt when it is straight, when seeing the needle spinning freely. Hope this makes sense Chris Quote Link to comment Share on other sites More sharing options...
stevo_gj Posted June 3, 2009 Share Posted June 3, 2009 Are you sure the float high is right on the front carb, it sounds to low to me, are yo looking for SU needles or Hitachi ?, I just did the same things to my carbs, syncing air flow and attempting to get mixture correct. Air flow was pretty easy but I wasn't really sure what I was doing with the mixture. It seems like its running well though so apparently my guess and check methods were successful Funny someone should mention high floats. When I was tinkering with my flat top SUs I discovered that when I put my fingers in to lift the cylinder up I could feel slightly more fuel in the front carby than in the rear. I also had the gunson colortune plugged in and it was showing me that the front 3 cylinders would initially run with the right mixture then slowly get a bit rich if left at idle. I am thinking this is related to the float being higher in the front carby, and if I wasn't getting rid of these carby's then I would have to adjust this. I have also done the test where you lift each piston seperately to check the others mixture.... I was attempting to do this, but I wasn't sure exactly what results I was looking for, could someone elaborate on how to do it correctly? Quote Link to comment Share on other sites More sharing options...
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