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DanLewis
Jedi Trainee
Offline
Many months ago I replaced the generator in my Bugeye with a modern alternator. Of course that meant converting the tach to electronic. Initially, I purchased an old RVC (voltage sense) Smith's tach on eBay, and used it to replace the internals of my original Bugeye mechanical tach while keeping the original Bugeye face and needle. That required drilling two very small holes in the face to align with the mounting holes on the front of the RVC mechanism. Also, the pointer on the Bugeye tach was a tiny bit loose on the shaft of the RVC tach, which I solved with a tiny bit of rubber cement.
NOTE: Using the RVC also requires converting the car to negative ground.
Ever since the original conversion, I've had problems that I attribute to the age of the RVC electronics. The needle would sometimes jump way up and read about 2,000 rpm too high and stay there for several minutes. I tried replacing all the capacitors, but the problem persisted. I think it was due to the fragile germanium transistors they used back in the day (and that no one uses anymore).
Last week I decided I'd had enough. I did a Google search and found a company (www.spiyda.com) that sells a printed circuit board designed to go inside a Smith's tachometer, and replaces the old electronics with a new modern integrated circuit. It's marketed as a way to convert an RVI (current sense) tach to an RVC tach, but as I suspected it worked perfectly well as a replacement for the old circuit board in my RVC tach.
I bought their board through eBay for $69 + $6.40 shipping from the U.K. It came in less than one week. Search eBay for "Smiths RVI to RVC Tachometer conversion board includes calibration cable". The board fits inside the tachometer can and mounts to the RVC mechanism using the same screws that held the original printed circuit board. Spiyda provides a cable that you connect to your laptop for calibration; you download a sound file from their site, play it, and turn a tiny potentiometer to adjust the setting. 'Couldn't be easier!
The only downside to this conversion is that the RVC mechanism doesn't allow for quite as much angular rotation of the needle as the old Bugeye tach so that it can't go all the way to full scale and stops around 5500 rpm. That's not a problem for me because I never push my engine that hard. :fat:
If anyone here decides to try this same conversion and has any problem, let me know and I'll try to answer any questions.
'Best,
Dan
NOTE: Using the RVC also requires converting the car to negative ground.
Ever since the original conversion, I've had problems that I attribute to the age of the RVC electronics. The needle would sometimes jump way up and read about 2,000 rpm too high and stay there for several minutes. I tried replacing all the capacitors, but the problem persisted. I think it was due to the fragile germanium transistors they used back in the day (and that no one uses anymore).
Last week I decided I'd had enough. I did a Google search and found a company (www.spiyda.com) that sells a printed circuit board designed to go inside a Smith's tachometer, and replaces the old electronics with a new modern integrated circuit. It's marketed as a way to convert an RVI (current sense) tach to an RVC tach, but as I suspected it worked perfectly well as a replacement for the old circuit board in my RVC tach.
I bought their board through eBay for $69 + $6.40 shipping from the U.K. It came in less than one week. Search eBay for "Smiths RVI to RVC Tachometer conversion board includes calibration cable". The board fits inside the tachometer can and mounts to the RVC mechanism using the same screws that held the original printed circuit board. Spiyda provides a cable that you connect to your laptop for calibration; you download a sound file from their site, play it, and turn a tiny potentiometer to adjust the setting. 'Couldn't be easier!
The only downside to this conversion is that the RVC mechanism doesn't allow for quite as much angular rotation of the needle as the old Bugeye tach so that it can't go all the way to full scale and stops around 5500 rpm. That's not a problem for me because I never push my engine that hard. :fat:
If anyone here decides to try this same conversion and has any problem, let me know and I'll try to answer any questions.
'Best,
Dan
Just ordered mine
