dwell meter

billfish

billfish

Senior Member
I just bought a dwell and tach meter, when it arrived it said for 12 volt systems. Will this work on my 1951 ford 6 volt system?

I hooked it up and the dwell and rpm readings look right
 
Some meters have their own power supply, and some meters use the car's power.

The ones that use the car's power have to be able to toggle between 6 or 12 volts or else you're screwed.

Try this trick: Walk into your nearest auto parts store and ask them if they have a dwell meter. Watch all the young-uns stare at you like you came from Mars.
 
Its been some time since I used one, but think its powered by the power to coil then other lead to ground.
Are there only 2 wire to meter.
 
actually the dwell reading looks messed up, when I open the gap in the points the dwell reading gets higher and that's backwards I think? The car calls for a dwell of 28 but when I open the gap to get a reading of 28 the car runs lousy. If I use a feeler gauge and set the gap to .015 (what the specs call for) the car runs great but the dwell meter reads 22.
 
The old Sears dwell-tach I have uses the coil power, and won't work worth a darn on 6v. There's no way to power it off a different battery.
 
I use a cheap trickle charger to power my tach dwell meter--paid about $8 for it at harbor freight-works great or you could just use a small 12 volt lawnmower battery if you need it portable.
 
The meter only has two leads, one for the coil and one to ground. No place to hook up 12 volt power supply.
 
maybe i'm getting old, but how can you go wrong when you set your points with a feeler gauge. at least you would know your setting was. from an old schooler.
 
billfish said:
The meter only has two leads, one for the coil and one to ground. No place to hook up 12 volt power supply.
Click to expand...

With 2 leads you need the power that flows thru the points.
I never saw much use for a dwell meter with older cars.
Now if you have a GM car with the window in dist cap that about the best use for it. I have found with feeler gauges add .001 or .002 to spec. this will allow for wear it. Put some grease on cam.
 
billfish said:
I just bought a dwell and tach meter, when it arrived it said for 12 volt systems. Will this work on my 1951 ford 6 volt system? I hooked it up and the dwell and rpm readings look right
Click to expand...


The tach dwells that I've used, or own, have to be switched from 6 to 12 V, or re-calibrated. My Accurate BT-162 two-lead is calibrated to the system voltage, while the Sun TDT-11 with internal batteries simply has to have the pointer zeroed. Both these, along with many other quality older meters, are still available at auction sites and swap meets.


Tommy Caruso said:
maybe i'm getting old, but how can you go wrong when you set your points with a feeler gauge. at least you would know your setting was. from an old schooler.
Click to expand...


Using a feeler gauge to set points may allow the engine to run, but is far from an accurate method. Point condition, and variance in using the gauge, can result in dwell readings all over the place, and since dwell directly affects timing, having correct dwell is one of the first and most important steps in good engine tuning.
Bottom line, a dwell meter, timing light and vacuum gauge are basic tools for anyone serious about performing tune ups on older breaker point engines, imo. :)
 
Last edited:
V8 Bob said:
The tach dwells that I've used, or own, have to be switched from 6 to 12 V, or re-calibrated. My Accurate BT-162 two-lead is calibrated to the system voltage, while the Sun TDT-11 with internal batteries simply has to have the pointer zeroed. Both these, along with many other quality older meters, are still available at auction sites and swap meets.





Using a feeler gauge to set points may allow the engine to run, but is far from an accurate method. Point condition, and variance in using the gauge, can result in dwell readings all over the place, and since dwell directly affects timing, having correct dwell is one of the first and most important steps in good engine tuning.
Bottom line, a dwell meter, timing light and vacuum gauge are basic tools for anyone serious about performing tune ups on older breaker point engines, imo. :)
Click to expand...
Also to get the correct dwell it needs to be set with the correct dwell at the correct rpm. This was easy on GM type distributors. With Ford etc you had to use the starter and set the dwell and then start it and run it at the correct rpm to get your reading to see how many degrees you are off and correct, and check again.
 
Marv said:
Also to get the correct dwell it needs to be set with the correct dwell at the correct rpm. This was easy on GM type distributors. With Ford etc you had to use the starter and set the dwell and then start it and run it at the correct rpm to get your reading to see how many degrees you are off and correct, and check again.
Click to expand...


Correct. Single point Fords are 27 degrees, while Chevy conversions are 30 degrees, both at idle rpm.
 
you talk about point condition when setting them with a feeler gauge, well you wouldn't set them with pitted points if you consider yourself a good mechanic . and furthermore if you know how to use a feeler gauge properly there would be no variance in the setting! it gets me mad to think that you can't even post a simple reply without somebody posting a smart-alec response , from feeler gauge happy, Tommy Caruso.
 
Tommy, seeing a stable dwell assures you all lobes are consistent and there is no bearing wear in the distributor. Of course this can only be done on a machine to be really accurate.

Lonnie
 
Last edited:
Lonnie, the only point i am trying to make is what did the great mechanics from the 20's, 30's and 40's do without dwell meters.
 
back to the original question, does anyone know if you can use a 12 volt two wire dwell meter on a 6 volt engine.
 
If you try it I think it will read on the low side.
its like a meter and 12 volt will draw less current so lower reading.
If you see smoke you didn't need it anyway.
 
I think it depends on the meter, I had one that didn't care, (it didn't like salt water though), another one I had did care.

perhaps you could make a tempoary 12v power for the ignition and see if the readings stay the same.
 
If you connect it to a pre-1956 Ford is will be 6-volt at the coil. If you connect it to a 1956 or later Ford with the proper ballast resistor, it will still be very close to 6-volt. No ballast will be 12-volt. If it is a 12-volt powered meter, just use a 12-volt battery to power it. I've done that plenty of times with timing lights and such. You just nead a common ground between the battery and the car.
 
You must log in or register to reply here.
Back
Top