Build Log: December 9, 2012

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In this segment, we mark a milestone. On December 3, 2011, the kit was completed by Factory Five. I didn’t receive it until December 19, but in at least one sense, the car is now over a year old. I recall estimating a year for the build. Obviously, I was just a bit off the mark...

My brother-in-law Randy came up from Atlanta to give me a hand last weekend. The first thing we did was take the body off of the car.

Next, we performed a four-wheel alignment using my new FasTrax alignment tool. Unfortunately, we were so heavy into the work that I forgot to take any pictures. The FastTrax tool is able to measure caster and camber and with the optional toe arms, it can measure toe as well. It is a neat little tool that pays for itself with the first alignment. It seems like we got things pretty close. The measurements were repeatable, even after taking the FasTrax off and putting it back on again. Once I get the car on the road, I’ll take to to an alignment shop to see how close we got it.

Next, we installed the “franken-pipes” and started working on getting the Webers tuned. I plan to write up a detained tutorial of this process, but will also hit the high points in this narrative. The first step was to get the carbs synchronized. All of the carb linkage keys off of the front driver-side “master” carb, which is actuated by the throttle linkage. It is linked directly to rear driver side carb by an adjustable tab, and that bank is linked to the passenger bank by an adjustable pushrod. The idea is to first synch the master carb to itself. That means we make sure that both barrels flow the same amount of air. This is done with a synchronometer - a device the measures air flow. It turned out that my master carb was not correctly synched to itself. One barrel was flowing slightly more air than the other at the same throttle opening. Unfortunately, there is no adjustment for this - you have to gently twist the throttle shaft. We did that by propping the butterfly for the “low” barrel open with the end of a large zip tie. We then used a thin block of wood to gently tap the other butterfly down. A few gentle taps brought both barrels into agreement. It turned out that three carbs needed this internal synching.

Next, the rear drivers carb is synched to the master. Following that, the two passenger carbs are synched to each other, and finally, the two banks are synched to each other.

Once the carbs were as closely synched as we could get them, it was time to start working on mixture. I started each carb out with the idle needle valve turned out 3/4-turn from fully closed. This is where the franken-pipes come into play. I have two wideband oxygen sensors and we used both to tune the idle mixture for each barrel:

That’s Randy doing the supervising. We tuned each barrel to an air-to-fuel ratio (AFR) of about 13.5:1 for idle. That’s a little rich, but I would rather start out too rich than too lean. Once that was done, we moved the sensors to the bung downstream of the collector to see what the whole exhaust stream looked like. By running up the RPM to 2500 to 3000, we could see what the mixture was doing and determine if the idle jetting was correct. We tried one jet larger than the stock jet, but concluded that the original jet was better. We were running consistently in the high 13.X:1 range, which seems to work well. As short road test showed that the low-rev performance is very good. I think we’re close on the idle jet. I’ll look at the main circuit and the accelerator pump circuit next.

After Randy went home, I started working on some little things that are on my punch list. I had not finished wiring the courtesy lights when I installed the dash the first time. Also, there were some small wiring changes I needed to make. So the dash came off again, and I tidied a few things up. I also added the door jamb switches for the courtesy lights:

I just riveted a small steel tab to the bottom of the door hinge. It seems to work well.

I also needed to install the Wilwood balance bar remote adjuster:

This will allow me to adjust the front-rear brake bias on-the-fly. It will be nicely hidden behind the dash, but still easily accessible if you know it’s there.

I recently changed the fuel pump since the one I had was cavitating a lot. In the process, I learned that the access panel in the trunk aluminum in not adequate to change out the pump. So, I made it bigger:

Now, if I ever need to change the pump again, it will be a lot easier. That’s all for now.

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