does anyone in christchurch know anyone that specialise in SU carb tuning?
i got a hold of the original owner in Hamilton and he had the SU's set up for av gas.
its running way to rich and can do with a mild street tune. Plugs were getting soot build up when idling around town and started to splatter and choke up when putting the foot down.
I have been told that Swift Automotive in Hornby specialise in SU carbs. . . ?? has anyone been to them before?
SU carbs
These engines can sometimes seem a bit hesitant with SUs at low revs if you doodle around town on a hot motor, on a hot day. I put it down to vapour lock with mine.
SUs are simple carbs, and once set should be good to go. Manifold vacuum lifts a piston to which is attached a tapered needle, which enters the main mixture screw,which is at the bottom of the carb. As revs rise, the needle lifts higher allowing more fuel through, so you have in effect a very efficient fuel metering system.
You need to feel at the very bottom of each carb, and there is a largish nut that can be screwed in or out to alter mixture
Screwing them in leans off the mixture. Screwing them out richens it. That is pretty much it . You should be able to feel a lump on one side of the nuts, so you can use that as a memory mark to go back to if you need to.
Take a mental note of where the nuts are set, so they can go back there if need be, then try screwing the mixture nuts in a quarter turn and see if it still drives OK. Remember these nuts are under the carbs, and they need turning clockwise to make them lean. This is clockwise AS IF you were lying under the engine. Do this with the engine running and listen for any alteration. (But not lying under the engine) lol
Do both carbs the same. If it is still OK try another quarter turn each. You ear will tell you.
Remember where you started with the adjustment so you can go back there.
There are other adjustments, such as float level, which also affects mixture, and also balance between carbs, but try the above first and see how ya go.
Try to get a Haynes 240-260 owners workshop manual. They come up on TM from time to time. Worth having.
SUs are simple carbs, and once set should be good to go. Manifold vacuum lifts a piston to which is attached a tapered needle, which enters the main mixture screw,which is at the bottom of the carb. As revs rise, the needle lifts higher allowing more fuel through, so you have in effect a very efficient fuel metering system.
You need to feel at the very bottom of each carb, and there is a largish nut that can be screwed in or out to alter mixture
Screwing them in leans off the mixture. Screwing them out richens it. That is pretty much it . You should be able to feel a lump on one side of the nuts, so you can use that as a memory mark to go back to if you need to.
Take a mental note of where the nuts are set, so they can go back there if need be, then try screwing the mixture nuts in a quarter turn and see if it still drives OK. Remember these nuts are under the carbs, and they need turning clockwise to make them lean. This is clockwise AS IF you were lying under the engine. Do this with the engine running and listen for any alteration. (But not lying under the engine) lol
Do both carbs the same. If it is still OK try another quarter turn each. You ear will tell you.
Remember where you started with the adjustment so you can go back there.
There are other adjustments, such as float level, which also affects mixture, and also balance between carbs, but try the above first and see how ya go.
Try to get a Haynes 240-260 owners workshop manual. They come up on TM from time to time. Worth having.
!972 240z
Retirement is great. Growing old sucks.
Retirement is great. Growing old sucks.
!972 240z
Retirement is great. Growing old sucks.
Retirement is great. Growing old sucks.
i leaned the carbs by half a turn lastnight and it wasnt blowing out black soot out the exhaust but a little white puff. engine was still cold so i am geussing it was just water. i put my hand near the tail pipe and it was a hell of a lot cleaner and didnt smell of petrol so much.
ill give her a test run tonight after work and see how they go.
ill give her a test run tonight after work and see how they go.
