Is there a way to set dwell using a Fluke meter? I have a Fluke 88. The instructions for the meter say to put one of the leads on the positive wire for the distributor but the only wire my distributor has is the one that goes to the negative side of the coil. Also, what should the reading be?
Some meters do dwell angle, but I dont think tthe 88 has that feature. I know the Fluke 78 does. I have an OTC 500 myself that I set dwell with. I set it to the dwell scale and hit the "cyl" button until it cycles to 8 cylinders. The red goes on the negative on the coil and the black goees to chassis ground. Works awesome.
A clean .017" feeler gauge is far cheaper, and 100% reliable. Just bump the engine over until you are on a distributor cam lobe.
Are the number supposed to vary much? What is the acceptable range? When I put the positive lead on the positive side of the coil it will give me a number and then go to zero. When I remove the probe it gives me another number. ---------- Post added at 08:59 PM ---------- Previous post was at 08:58 PM ---------- Maybe I'll try that. Thanks ---------- Post added at 09:18 PM ---------- Previous post was at 08:59 PM ---------- Ok , it's right at .017 with the feeler gauge.
Thats a great tip. I didnt realize there was a formula to convert duty cycle to dwell. I think the spec is .016
Instead of trusting spread sheets & formulas that might be mis interpreted, how about some simple logic. Points are mechanically designed to be closed 2/3s of the time, and open 1/3 of the time. On a 360 degree distributor rotation, each of 8 cylinders get 1/8 or 45 degrees. 2/3 of 45 degrees is 30 degrees. On a 6 cylinder its 60 and 40 degrees. Odd fire, figure in the "phantom" cylinders. If you disconnect the coil & cap from the points, and connect an analog ohm meter, it will read full scale (ANY scale) when the points are closed and back to the beginning when they are open. So when spinning the analog ohm meter should read 2/3 of full scale for any even fire engine. Another way, put a voltmeter across the operating points. Note the voltage with points open, you should see 1/3 of this when the engine spins. There is some error caused by coil interaction and voltage change from starter loading. Digital volt meters do not work well trying to average voltage. But a digital meter with DUTY CYCLE capability should be able to show the 1/3 or 2/3 (33% or 67%) figures. Bruce Roe
Answer: Bruce gave it way but the above formula should reference distributor (or cam) degrees as the angle units, and not leave it to be assumed that it's supposed to be crank degrees (like I would do by default). So 30 degrees dwell angle (distributor degrees) is 67% duty-cycle (and that is duty-cycle "low" or points closed, for reference).
Timonator, I have an older(70s?) Sears dwell meter I would be willing to sell. Used 3 times in absoultly new condition, in original box in like new condition with instructions. Currently on display in my rec room with matching timing gun. Pm me for details, pictures, etc,,,
:Smarty: Step away from the electronics! The feeler gauge can do no wrong! heh heh heh...do what you will, I'm just kidding.
