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Dwell meter?

The post about the '59 Nash Metropolitan hit a memory cord with me. How many of you Saturday mechanics still haved a dwell meter, much less know what it is and how touse it? Plus a timing light? I have these and also still have all my teeth! (Not so for my hair.)

I’m 28 and I have a timing light. Never herd of dwell meter though. enlighten me.

I’m an old geezer and to me, a dwell meter and a timing light are modern tools. I set the distributor points with a gap gauge or feeler gauge as we called them. I set the timing by feel. I would set it where I thought it belonged, then drive the car. If the engine pinged, I retarded the timing. If it didn’t ping, I would advance the timing until I got a slight ping under hard acceleration.

Cars are now almost beyond me, but I still know how to check the oil.

Oh, yeah. I still have dwell meter. And a timing light. Both are useless with my current vehicles.

Let the fun begin.

I also have a Uni-syn. I’ve offered it, free, to my friend who has an Austin Healey 100 M. For some reason he’s not interested.

Sure I have both a timing light AS WELL AS a Dwell meter… Why not? I’m 38 BTW age has nothing to do with being able to work on old style distributors. It would take me far too long to give a disertation on the useage of a dwell meter…it is needed and useful however even in present day…because the old stuff is still out there.

I fully encourage the principle of techs getting to know how and why to use the dwell meter…the things you learn on the “Old School” engines still hold water and I believe are essential to having a thorough understanding of todays engines…ALL of the principles still hold water and it gives you an appreciation of how advanced engines and their controls are today…In fact I think it is essential to know the OLD SCHOOL…before you can graduate…WHAT DO YOU GUYS THINK?

I’m not a Saturday mechanic, I’m a Monday-Friday mechanic. I have a dwell meter, bought it a few years ago. Pretty much right after I updated a lot of my hand-held diagnostic equipment to current, modern-day standards. Then one day an old car came in and I realized I had no way of checking/adjusting the dwell. Lots of shops no longer work on cars with carburetors and point-type ignition sytems.

“Dwell” is the distance, measured in degrees of a circle, that a set of breaker points in a distributor remains closed. This measurement is taken at the negative side of the coil with the engine running.

I agree.
One of the early tests our electrical shop teacher gave us was:

  • He pulled the wires and distributor from an engine.
  • He removed the points and condenser from the distributor.
  • He gave us a feeler gauge, a 12v light (to use as a continuity tester) and a shop manual.

We had to reassemble the above parts. The engine had to start on his first hit of the starter, and when he checked the timing with a timing light, it had to be very close.

I learned a lot of fundamentals and basics in that course that I still use.

I agree, although all I know is OLD SCHOOL. In the old days, when the points were closed, a magnetic field was built up in the primary side of the coil. When the points opened, this magnetic field collapsed and induced the high voltage in the secondary windings. While today’s cars don’t have ignition points, the ignition coils still work the same way.

I was highly confident that the stories you related were not out of old magazine issues but now we know for sure, I am joking, you know that don’t you?

The best guy to tune an engine that I ever met set the timing by “ear”. Years later, I learned that he was functionally illiterate, and had to quit being a mechanic when the engine diagnostics became too technical. You might be in the same league of quality old-time mechanics. I still remember the time that I was getting ready to leave on a Sunday to go skiing in Vermont, and my '74 Ford wagon (the one with the fake woodgrain on the sides) started to run rough. I called him at his home and he said to bring it over. He listened and then asked one question - “Did you recently drive in a snowstorm?” I said yes, and he said to replace the distributor cap - moisture had got inside and was making it arc across the electrodes going to each spark plug. He never touched the engine. I replaced the cap and it ran fine. He passed away a few years ago. Butch, I still remember you.

Digging through my memory bank I believe it will be 1984 as the year I last use a dwell meter professionaly,add 10 for the discrete timing light. I remember in the 70’s being able to hit 50 degrees dwell with a .016 feeler gague on VW’s time after time. My first boss would always write “tune up and scope engine” as we always used a Sun machine with all our tune-ups. I found many a high resistance spark plug connector or wire with the scope.

Ignition coils are a form of autotransformer and as such, do not have separate primary and secondary windings.

I have both a dwell/tachometer and a timing light. But those don’t come out until spring comes and everyone starts driving their classic cars.


I still have my dwell meter, feeler gauges timing light and hair, maybe a little less hair. I was in MN at the cabins and and the 15’ Sea Ray with a 1966 100 hp evinrude needed new dual points. My dwell meter was at home and I asked the guy at the auto parts store if they had a dwell meter, as I figured I would spend the 50 bucks assumed to get a new one to continue water skiing and tubing on the 2 week a year boat. I got a blank stare, so he called the old timer there and he said we have not had one of those for at least 20 years. A couple of more auto parts places with no luck. I suppose in some arcane way it is like asking for a hand crank handle for a model t, though I have one of those also.

I am 25 years old and do have a dwell meter and timing light. I still work on plenty of old Chevy V8s, and I do like to set the timing by the book, and if further adjustments are warranted, then I deviate. The one Chevy V8 I had that came with breaker points ended up getting updated to a coil-in-cap HEI system in short order. The last breaker point ignition I worked on, however, just needed to run well enough to move it, so I used what I had at the time for that operation and set the points with a matchbook.

I’ve got several dwell meters and several timing lights. The dwell meters only come out on my old contact point stuff and the timing lights on distributor equipped vehicles.

The timing light is used on a distributor equipped timing belt job to verify ignition timing even if the theory is that nothing will change during a job like this. The timing light can also be used to determine if there is any timing chain slop.

LOL…MARK you just brought me back to my youth…My Grandfather and Father both taught me to use a MATCHBOOK cover to set the points…I believe it was on my Rupp minibike…

The matchbook cover I believe is .015 in thick…and it will get most every engine at least running…LOL…YEAH those matchbooks can be a seriously HANDY DANDY piece of kit…I mean what other “tool” can you

Get any Chevy 350 Running…
Start a nice campfire and cook your trout
File down a set of burnt points
Lite a cigarette
Make a delayed fuse for a firecracker
…and a myriad of other household and mechanical duties…The GOOD OLE MATCHBOOK…YEAH BABY.


Yup…I have dwell meter with tach…and a timing light. Haven’t used it in years. Wife wanted me to through them out…didn’t have the heart.

That was true in the old days of Kittering ignition systems (points). In those days a coil was a tapped coil, one single winding with a tap lead in it. Todays ignition systems do use an autotransformer with a primary and secondary sharing a common ground.

BTW I still have my second dwell meter and my fourth or fifth timing light, as well as my teeth (most with crowns) and all my hair (mostly grey).