'55 Instrument Voltage Regulators
This morning, I received this email from Stan Reynolds in Grass Lake, Michigan regarding a problem he is having with his fuel gauge readings. He is a member of Yahoo Classicbirds and someone there recommended that he contact me for help with this problem. I have invited Stan to join us so that he can communicate back and forth with ya'll on this. Here is the problem he has with his '55 Tbird which has gone through a partial 6V to 12V modification prior to him buying it.
My name is Stan Reynolds, and I live in Michigan. Your name and email address popped up during a discussion on the Yahoo Classicbirds mail list regarding instrument voltage regulators. The person who recommended you said you are somewhat an expert on such matters, so I'm hoping you can also give me some advice with a problem I have.
I have a 1955 Thunderbird which has been (before my ownership) given a partial twelve volt conversion. The starter and window motors are still six volt and, although they spin at twice the speed intended, they still work and have done so for the twelve years I have owned the car. My problem is the fuel gauge has never registered over one quarter tank even when I know it to be full right up to the fill pipe. Several years ago, I replaced the sending unit in the tank with a new 12volt unit, but the result was the same. It's as if the full scale of the gauge has been compressed to the first 1/4 reading.
A few years ago, CASCO (a company in Ohio that sells classic bird parts) developed a "matched set" for cars like mine that includes a sending unit and a gauge that is matched to it. I suspect this may solve the problem, but have been reluctant to order it because it is very expensive and also requires removal of the instrument cluster, a job I swore I would never try again. I removed it once to replace lightbulbs, and spent the better part of a day trying to wrestle it back in place without unplugging anything.
In July of this year, a guy wrote to the mail list that he had the same exact problem with his '55 and that he had taken it to a place called Quality Coaches in Minneapolis. They had installed a "resistor", not sure where, and it solved his problem and the fuel gauge now works normally. I contacted this guy, and he gave me the name and phone number of the person he had worked with at Quality Coaches, but when I contacted them they acted as though they had no idea what I was talking about.
So, after a long-winded introduction of the issue, I am hoping you might have an idea what the other '55 owner was referring to. I am also hoping that if you know of such a resistor or other device, that it could be installed in the trunk on the feed line from the sending unit.
Thank you, and I apologize for such a long message.
Grass Lake, Michigan
55 red and 57 white E"
I have replied to him already and given him some information regarding how the factory handled the step down of the 12V from our system to 6V for the gauges. I sent him the link that Alexander created many years ago on how to fix this problem and adjust the readouts on our Squarebirds. It may be that this is the route that he might have to go to also, as someone apparently did. But when he talked with that coach company, no one seemed to know what he was talking about. Can ya'll help? I asked him to watch this Forum for responses.