Decided to stop guessing and bought a colortune

[Zedyone_kenobi]

I do have a go pro camera that could be used for this. But i would need an extreme amount of light under the hood to make it work.

But it could be fun. I assume this is all under load we are talking about Blue. I find the SU a very fascinating carb. I have read quite a bit on it and I do understand its function for the most part.

What kills me is when I installed these carbs from Z therapy, they performed flawlessly to 6500 rpm.

I have since had my dizzy rebuilt and recurved but nothing extreme. I somehow think this is not fuel related any more. My SU's are fresh off a Z therapy rebuild and they look and feel amazing. The car idles and performs FLAWLESSLY below 4000 rpm. But its a backfiring wall at that point.

[SteveJ]

I do have a go pro camera that could be used for this. But i would need an extreme amount of light under the hood to make it work.

But it could be fun. I assume this is all under load we are talking about Blue. I find the SU a very fascinating carb. I have read quite a bit on it and I do understand its function for the most part.

What kills me is when I installed these carbs from Z therapy, they performed flawlessly to 6500 rpm.

I have since had my dizzy rebuilt and recurved but nothing extreme. I somehow think this is not fuel related any more. My SU's are fresh off a Z therapy rebuild and they look and feel amazing. The car idles and performs FLAWLESSLY below 4000 rpm. But its a backfiring wall at that point.

I was thinking about your previous post before I read this one. My line of thought was that if you believe that your colortune results were good, then too much unburned fuel out the exhaust at higher engine speed might be an indication of an ignition timing problem. (Mind you, I don't claim to be an engine expert.) How is your vacuum advance?

As an aside, if you ever decide to go with the ZX distributor, vacuum advances are still available for those distributors.

[Zedyone_kenobi]

I have a very recently rebuilt dizzy form Advance Distributors. I run 14 degrees static timing and max out at about 35 degrees with mechanical advance, I have tried this with both the vacuum advance on and off, and still get teh same results. Perhaps my pertronix is going bad. I have a brand new pertronix coil as well. Part of me thinks this very well may NOT be carb related.

[hogie]

---

For what it is worth, I was lean popping from the carbs and had jerky acceleration. Adjusting it a bit richer gave me some power back and got rid of the pop.

Edited December 16, 2011 by hogie

[Healey Z]

Sorry for the delay. Work, family and the holiday got in the way. My Dad is going to give me a hand on Friday, so I can take my time, adjust the air/fuel while watching and taking pictures of the flame color. Here is my plan, let me know if you would do something different.

1. Adjust carb to two turns open as the baseline

2. Warm the car up

3. Remove air horns/filters

4. Adjust idle, balance the flow with the unisyn at 900, 2500 rpm

5. Replace air horns/filters

6. Install colortune on cylinder 2, adjust mixture to bunson blue throughout rpm range

7. Do the same on cylinder 5

Thoughts on the plan?