Tuning Weber carb with A/F gauge

Woah, that looks great! Just curious, did you run the OZ head with a carb before you started the conversion? It would be interesting to hear the difference made with just the change to FI itself.

I've tried to use that lean best idle procedure on both carbs, but never had luck. I always end up having to idle off the main's to get it to run at all. And that's after I stepped up the idle jets to every size in the jet kit I got from redline. I've sprayed all over for vacuum leaks, but can't find anything. I may try again, but this time pull the PCV and plug the line and see if that's causing problems.

How much extra timing did you see work for you with the Weber? I'm at 14 right now (DSII with MSD 6a)... I'm guessing if I try to do more, then I'd have to recurve so my total isn't too high. No pinging right now though.

I haven't run the OZ head with a carb yet, and probably never will. The conversion process is going to be complicated and once I start I'm going to push through to completion, so setting up the carb would be an unwanted distraction.

Weird that you can't get either carb to idle. I do have to crank my idle screw (the one that moves the throttle plates) further than recommended, so that I'm beginning to uncover the transition holes, but just so. Worth noting that the description of where that screw should be positioned was inaccurate on my carb. Hey say something like "turn the screw until it makes contact and then only 1/8 turn more." That didn't work for me. I had to flip the carb over and crank the screw to the desired position while watching the throttle plate/transition hole relationship, and then mark the screw, install the carb and adjust for lean best idle from there.

Monitoring vacuum helps, and I ultimately played with striking a balance between adjusting the two idle circuit mixture screws (after determining the best jet) for max rpm/smoothest vacuum signal, backing out the idle speed screw as much as possible, and then repeating the process until I got the best result. As for timing, 14should be plenty, although I'm running about 16 degrees on a recurved dizzy. I'm at 6000 feet and have a more aggressive cam than you, though.

Did you try raising the float level?
Fired my car up yesterday for the first time in about six months.
Was having idle problems as well, lumpy, wouldn't stay running.
I adjusted the float level and it solved the problem.
Idles at 1000rpm and 800 in gear.

I haven't messed with the float yet, but I was planning on trying that out as well. The Clifford site says to raise it so the upper tip of the float is 17.5mm from the gasket surface... I'll give that a shot and see if it makes a difference.

kerb12":1gdzfdwb said:

I haven't messed with the float yet, but I was planning on trying that out as well. The Clifford site says to raise it so the upper tip of the float is 17.5mm from the gasket surface... I'll give that a shot and see if it makes a difference.

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xctasy":1gdzfdwb said:

The Reliant manual and the Ford one give float height settings of 40.0 mm (brass) and 34.3 mm (plastic)

With F7's and the the F6 based F THIS Swatson 454 ran, he had a 18mm float drop, but its specified as 18mm from the gasket to the top of the float without depressing the ball and spring in the needle valve.

Some suppliers use the 38/52 float level with the F50 tubes, which is 14 mm float drop. Swatson 454 said the stock settings of 14mm float drop sounds pretty high

Factory defaults of 40/50 are way too high with a float drop of 10 mm, but they are for little PRV 2.6 V6's, Cologne 2.8 and UK Essex 3.0 V6's without a lot of low end vacuum. I6's have a lot more torque and low end vacuum.

On the Jeep Forum,
http://www.jeepforum.com/forum/f8/weber ... dex13.html
uptillnow and Swatson454 (Shawn) said this
Originally Posted by swatson454 View Post
Here's an example of what I'm talking about, courtesy of uptillnow.

The pattern of large holes at the top of the F-50 bleed off an enormous amount of signal compared to the hole pattern of the F-6. This requires more rpm to finally pull fuel in from the main circuit. Unfortunately, by this time the idle jet has already given all its got and you end up with the lean spot you're seeing.
I hope it helps.
Shawn

Typically in the 38-DGES we use the F50e-tubes, using more and larger air holes. Adjust the float level to 18mm from the gasket to the top of the float (without depressing the ball and spring in the needle vale). This typically works well for “most” applications. The F6, as Shawn stated has fewer air holes, and lower on the E-tube. With less air hole’s the main circuit will tip in sooner, and be a richer air fuel ratio. So now we would need to add some of that air we took away from the original F50 until we can get what we are looking for. The float level can add or subtract overall fuel volume at the tip in, or in the middle of the main circuit, or at high RPM or MAX power.
ARE YOU STILL CONFUSED??
Emulsion tubes become “black magic” when we don’t have a wide band O2 sensor or a way to measure fuel and power changes like a dyno.
Flame suit on… Shawn, get the fire extinguishers

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Others have put DGES's on small M110 Twin Cam I6 Benzes, and found that they can get F43's, F61's and F50's to work, but they are smaller engines with more valve overlap

http://speedtalk.com/forum/viewtopic.php?f=1&t=26933

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