Changing The Ammeter Gauge To Newer Voltmeter

After redesigning and building new wiring harnesses for my Corvette, the old ammeter gauge wasn't really working. I did not really know how it was supposed to work in any case. If I understood correctly, it just showed which way the current was flowing: to or from the battery. With the new harnesses it always stayed dead center, so it wasn't really that useful. A voltmeter on the other hand would be much more informative as I could see how the alternator was working.

1976 Corvette is the last year that uses the ammeter and the 1977 model already has the voltmeter. I bought an used gauge a few months ago and decided to switch them. I heard that the sizes and shapes should be exactly the same but I would need to drill one hole to the back of the gauge panel. This information proved correct and one new hole later, the new voltmeter gauge was installed.

Then the troubles started. I reassembled the console and tested the gauge. A few hours of testing, fiddling and Googling later I learned that the voltmeter must be connected exactly correct or it won't display right voltages. I found an informative page from "European Corvette", that explains what's needed in the gauges. And this is needed for the voltmeter:

• Lowest connector must have the positive wire.
• Lower and upper connector must have the correct plastic resistor (with light blue sticker) between them. This resistor should have 125 ohms.
• The third connector is ground. No wire is needed as the holding nut should touch the body of the console.

With these points in mind, I went through the wiring diagrams. Most likely the wiring junction in the engine compartment would be the best place where to add the voltmeter positive wire. Then the gauge would show the true alternator voltage. Unfortunately then there would be voltage in the wire all the time. I needed this to happen only when ignition was on. Luckily this was easy as all the pink power wires for the other gauges work just like that. So I just added a 10 centimeter wire from the oil pressure gauge to the voltmeter. After all the work, this is how it looked:

I turned the ignition on and the gauge seemed to work. I checked the battery with a multimeter and got a bit over 12 volts. Unfortunately the fuel gauge didn't seem to work even after I changed it too. It is still showing too much. I'll have to investigate it further.

American Sale Document

While trying to get the engine running and waiting for the weather warm up a bit, I happened to find the original eBay sales document of my car. I guess eBay saves them as PDF files after the auction has ended. Well, here it is:

http://dl.dropbox.com/u/132090/corvette_ebay.pdf

Too bad that the images are really small and some of the text is hidden but it was still fun to read through it. All I can say is that bull*hit was strong in this one. Some of the gems include:

• Chance of a Lifetime Project Car
• Good Mechanical Condition
• Re-Built Engine
• Transmission Recently Re-Built
• Needs Shift Cable

Let's see:
"Chance of a lifetime project car": yeah, one that you will have to work on for a lifetime to get it running.
"Good mechanical condition": umm, there wasn't a single working electrical equipment, bushings and bearings were shot, rust damage was covered up with urethane foam, all wiring needed to be changed etc.
"Re-built engine": the block was in pretty good condition but the heads were cracked and needed to be replaced or the engine would overheat.
"Transmission recently re-built" and "needs shift cable": no, the cable was fine, the shifter linkage inside the transmission was not. The linkage bolt was loose and it did not shift properly.

So yeah, I guess this seller is as POS lying bastard as any old car dealer...

The Corvette Lives Again!

Finally, after days of frustration, fiddling and tuning the carb and distributor I got the motor running again! I began by installing the intake manifold and valve covers. The valve cover gaskets were also pretty perished so I installed new, better ones.

I heard that these should last a long time and allow me to remove the valve covers and reuse the gaskets. Next I bolted the carburetor on the engine and connected all the vacuum hoses and cables. Final piece was the distributor. I tried installing it the same way as when I removed it and after a few tries everything seemed to be in the correct place and looking nice.

After double checking that I got everything right, it was time to try starting the engine. It cranked fine but would not run. The engine just shuddered and died after a while. I checked the carb and something was wrong. When pulling the throttle, the accelerator pump did not squirt gas. Only a few drops fell out of the nozzles. But this wasn't the only problem. I had some gas in a canister and poured a little straight in the barrels. This should allow the engine to run for a little while but it did not. Most likely the ignition was off too.

I decided to start from the distributor. I took it off and needed to get the number 1 piston to TDC. Unfortunately more troubles followed when I started turning the engine by hand from the balancer bolt. Pretty soon the ratchet was turning but the bolt wasn't. I couldn't see it but by feeling it, I noticed that the bolt was almost completely round. Only good thing was that the socket still hooked enough to open it. I went and bought something better to replace it.

Old bolt. I'm glad I got it out without too much fighting.

Now turning the engine by hand wasn't a problem any more. Finally I got the crank to the right position and installed the distributor again. And the engine still did not run. Just shuddered and died. Next I investigated the carburetor. After some googling I found that the plastic accelerator pump cam can be installed in two ways. I wasn't sure I had got it right so took it out. It was, in fact, correct so I just screwed it back in. But this made a huge difference! The accelerator pump worked perfectly after this! Perhaps it just did not fill with fuel while under the throttle lever pressure all the time?

Now that the gas issue seemed to be solved, it was time to go back to the ignition again. The engine still did not run so I got the distributor out one more time. It was time to turn to Google again and I found this excellent video from YouTube:

I watched through all three parts and went back to work. It did seem that the ignition was about right so I set the distributor back in and fiddled with the carb a bit. I tuned the idle screw, mixture screws and accelerator pump and tried starting after each change. And behold! After a few tries the engine actually ran! Pretty poorly but still ran enough for me to get out of the car and turn the distributor. Pretty soon I got the ignition timing correct and idle speed to normal.

After all the work, it at least felt that the engine ran smoother and revved better than before. Naturally I would have to take the car for a test drive to see the final situation. Unfortunately this would have to wait for a month or two until the snows melt... The engine bay looked better though.