The Ford Barn

bill4704 · 03-26-2026, 08:10 AM

This is an interesting electrical problem. I own a 1934 Ford pu with a 59AB flathead. I wanted to install a simple tachometer to see what rpm I am really doing. Over the last 6 months, I have purchased ( and taken back) 7 tachometers from Walmart, Ebay, Pet Boys, Advanced Auto and other stores. All were made in China.
I typically start the engine, hook up my 1960's shop dwell/tach meter, then connect the new tachometer to see if it will work. About 50% of them registered well off from my shop tach. The rest worked OK at first, but burned out within a mile of driving after installation.
The coil had 1.5 ohms resist. The ballast resistor, 1.5 ohm. About 8.8v on the + side of the coil when running and about 6v on the distributor side. I can live without a tach, but the problem is driving me nuts! Any suggestions?
Thanks, Bill

03-26-2026, 08:10 AM	#1
bill4704 Junior Member Join Date: Mar 2025 Posts: 9	Burned-out tachometers This is an interesting electrical problem. I own a 1934 Ford pu with a 59AB flathead. I wanted to install a simple tachometer to see what rpm I am really doing. Over the last 6 months, I have purchased ( and taken back) 7 tachometers from Walmart, Ebay, Pet Boys, Advanced Auto and other stores. All were made in China. I typically start the engine, hook up my 1960's shop dwell/tach meter, then connect the new tachometer to see if it will work. About 50% of them registered well off from my shop tach. The rest worked OK at first, but burned out within a mile of driving after installation. The coil had 1.5 ohms resist. The ballast resistor, 1.5 ohm. About 8.8v on the + side of the coil when running and about 6v on the distributor side. I can live without a tach, but the problem is driving me nuts! Any suggestions? Thanks, Bill