Tachometer showing double

#1
Hey everyone. My 1966 Series 1 P6 SC has had a tachometer and clock from a TC fitted at some time in the past. This is a plus for me. It has the 7000 RPM red line, so I am pretty sure it's from a TC not a V8. But, it's showing double the actual RPM. It seemed wrong and so I verified this with an automotive multimeter that has a tach function. Any ideas how this could be happening? If it were the tach with the 6000 RPM red line I would just guess it was from a V8 and so showing double. But at this point I'm guessing it's just not hooked up properly. Any help appreciated.

Cheers,
Karl
 
#3
Thanks @sdibbers. Yeah, that's what I thought. It's the 4 cylinder one, so it must be a different problem. I am not sure if it's an RVI or RVC tachometer (I just learned about this) and will try to figure out which one it is if that helps.
 
#4
To be clear, the tach redline starts at 6,000 and the tach's highest mark is 7000? Is it reading exactly double, or just very high? Does the car have points, or an electronic ignition? It'll say RVI on the bottom of the dial if it's a RVI.

Yours
Vern
 
#6
To be clear, the tach redline starts at 6,000 and the tach's highest mark is 7000? Is it reading exactly double, or just very high? Does the car have points, or an electronic ignition? It'll say RVI on the bottom of the dial if it's a RVI.
Yes, the red line is at 6000 and the end of the red block is at 7000 RPM. It's from a TC. It appears to be 2x at idle, but I can't actually say for sure at high revs because, working solo, I can't tell what it says on the gauge in the car while under the hood/boonet with the multimeter. I will get my daughter to help me read it and see if it's linear.

I didn't know you could just read the face of the gauge to determine RVI vs RVC. I've now checked and is an RVI gauge. Also, this may be related: I figured out the car has a 2200 engine in it.
If it were from a V8, it'd read half. Sounds like RVI with electronic ignition to me.
Yes, you are right about the reading: it would be half. I was thinking about it the other way around. But, I verified that the distributor is running points and condensor.
 
Top