TR2/3/3A For TR3 SU's what is the correct jet height below the bridge?

[karls59tr]

I always thought the jet height was supposed to be level with the bridge???

 

[charleyf]

I always thought the jet height was supposed to be level with the bridge???

Wrong.... That is about where the jet should be before starting the adjustments, which is then 12 flats down.
Charley

 

[karls59tr]

Wrong.... That is about where the jet should be before starting the adjustments, which is then 12 flats down.
Charley

So what would the correct jet height below the bridge be for the SU's?

 

[charleyf]

So what would the correct jet height below the bridge be for the SU's?

I hope you have access to the procedure for adjusting the carbs. There is the 1. all of the way up starting point for the jet. Then there is 2. the 12 flats down beginning point. Then there is 3. the final level. This level will depend on your individual car.
Charley

 

[karls59tr]

I hope you have access to the procedure for adjusting the carbs. There is the 1. all of the way up starting point for the jet. Then there is 2. the 12 flats down beginning point. Then there is 3. the final level. This level will depend on your individual car.
Charley

OK. I see that the level depends on the individual car. I suppose what caused confusion for me is that I have seen on various forums where people have stated a specific point below the bridge where the jet should be.

 

[poolboy]

I think Charlie outlined it.
From level with the bridge, lower it 12 flats....that's your baseline; measure it if your want to know the actual depth.
From there you'll need to see how the engine likes that setting. If it doesn't and you think you can make it better then that's where the jet's adjustability comes into play
With the ZS carbs that have fixed jets and adjustable needles..the fixed jet sits about 1/10 of an inch below the bridge and the adjustable needle is set at the middle of it's adjustment range...that's the starting point, baseline.

 

[charleyf]

OK. I see that the level depends on the individual car. I suppose what caused confusion for me is that I have seen on various forums where people have stated a specific point below the bridge where the jet should be.

The condition of the individual car to me would I believe, include float levels, carb throttle shaft condition(air leak), valve adjustment, timing, height the needle is mounted in the piston and I am sure others.
And even more important is that you have 2 carbs that need to be adjusted together.
Charley

 

[KVH]

As indicated, I may need to recheck my valve timing because one of my carbs is set with the jet about 1/32” below the bridge, and open only 6 flats from closed. I will take the valve cover off soon and see. Love this constant learning experience. It’s been 54 years of it, and something new all the time.

 

[mctriumph]

The idea is that the jet is below the bridge AND the float level fills the jet up to the top with fuel.
Senior Venturi then does the rest......
Mad dog