1959 carburetor adjustment (230hp late car)

[Rob M.]

Hi all,

My 1959 Corvettte 230hp (single 4 barrel carb) stumbles a little bit when I reach 4000+ RPM. I get the impression it is running too lean at these higher RPM's (no backfires occure). Where do I find an easy to use adjustment manual for this particular problem?

regards,
Rob.

[Jim L.]

Rob,
It would be worth your while to temporarily install a wide band air/fuel gauge and to verify your hunch before making any changes to the carburetion. Such gauges are (relatively) cheap and the information they provide eliminates guesswork.
Jim

[Rob M.]

Rob,
It would be worth your while to temporarily install a wide band air/fuel gauge and to verify your hunch before making any changes to the carburetion. Such gauges are (relatively) cheap and the information they provide eliminates guesswork.
Jim

I found many of these guages but where and how would I mount the sensor of such a guage?

[Jim L.]

I found many of these guages but where and how would I mount the sensor of such a guage?

Innovate Motorsports produces a device which lets you temporarily install an O2 sensor at the tailpipe outlet. I believe their term for this piece is "tailpipe clamp" or maybe "exhaust clamp". It looks like this:

clamp.jpg

I use one of these when I calibrate Rochester fuel injection. Installed on my '60, this is what it looks like:

7291-re.jpg

[David H.]

Rob,
It would be worth your while to temporarily install a wide band air/fuel gauge and to verify your hunch before making any changes to the carburetion. Such gauges are (relatively) cheap and the information they provide eliminates guesswork.
Jim

Jim

What guage do you use? Seem to range from around $70 to a few hundred.

Thanks

Dave

[Jim L.]

Dave all of the equipment I use is from Innovate Motorsports because I can customize it for the exact data I want to see. This was particularly valuable when I was developing a series of FI modifications to mitigate the FI fuel percolation problem.

For monitoring only air/fuel ratios, I use the LC2 controller and the DB gauge ( think that's the correct nomenclature). Here is a link to them at Summit Racing:

https://www.summitracing.com/parts/inn-37950

The tailpipe clamp I mentioned doesn't have to be used with only Innovate equipment. AFAIK, all O2 sensors have the same threads so the clamp can be used with any other brand of air/fuel gauge.

Jim

[David H.]

Dave all of the equipment I use is from Innovate Motorsports because I can customize it for the exact data I want to see. This was particularly valuable when I was developing a series of FI modifications to mitigate the FI fuel percolation problem.

For monitoring only air/fuel ratios, I use the LC2 controller and the DB gauge ( think that's the correct nomenclature). Here is a link to them at Summit Racing:

https://www.summitracing.com/parts/inn-37950

The tailpipe clamp I mentioned doesn't have to be used with only Innovate equipment. AFAIK, all O2 sensors have the same threads so the clamp can be used with any other brand of air/fuel gauge.

Jim

Jim

Thanks

Dave

PS: Jeff likes doing those "How to do it" things after NorCal zoom meetings. I think you giving an intro Air/Fuel measuring school would be very useful. Just a thought!!

[Jim L.]

That's an interesting idea, Dave!

From the questions and answers I've seen which deal with dialing in carburetors by guess and by golly, I agree that many folks could benefit from knowing how to measure actual air/fuel ratios and how to use that information properly.

Hmmmmm..........................