high reading on 1955 tach
03-24-2014, 01:37 AM
#1
Burning Brakes
Thread Starter
high reading on 1955 tach
my tach has just started to act up. at 65 mph my tachometer is showing 6000 rpms. what is causing this high reading?
03-24-2014, 06:07 AM
#2
Safety Car
What is it at idle?
If you haven't changed the generator tach drive hardware, it sounds like a internal gauge problem.
You can disconnect the cable from the generator and connect to a drill of known RPM's, run it in reverse and see what the tach reads.
If it's in the gauge, seems to me that the cup housing may have loosened and threw off the calibration. Could be a simple fix if you get inside it.
Rich
If you haven't changed the generator tach drive hardware, it sounds like a internal gauge problem.
You can disconnect the cable from the generator and connect to a drill of known RPM's, run it in reverse and see what the tach reads.
If it's in the gauge, seems to me that the cup housing may have loosened and threw off the calibration. Could be a simple fix if you get inside it.
Rich
03-26-2014, 03:09 PM
#3
Advanced
What does the tach read when the engine is shut off? It should be at zero RPM, if not, maybe as Rich said, the housing has shifted. I am not 100% sure but I think they are indexed to prevent that.
03-26-2014, 03:26 PM
#4
Burning Brakes
Thread Starter
03-27-2014, 05:28 AM
#6
Safety Car
Wow, that's strange Roy.....Only way I could think that could happen, is if the squared ends got rounded off and slipping inside the square ends of the cable housings. But if it's slipping, wouldn't it run "half" speed? He's reading double. Maybe you were thinking half speed.
I suggested usinga drill, with a rpm rating for reference, and run it from the generator end of the cable. I'd really be curious what happens.
I suggested usinga drill, with a rpm rating for reference, and run it from the generator end of the cable. I'd really be curious what happens.