Engine: Tune up tools

[Brianbo]

Are there tach/dwell meters for my ‘52 Champion? I would like to know how fast it idles. Also, I would like to get an idea of how fast the engine is turning at different road speeds. Is there a chart/graph for that? I figure I could cheat the timing light with an induction sensor that clamps on the plug wire.
thanks
brian

[StudeRich]

Most Dwell/Tach/Voltmeter Combo's will work on 6 Volt Positive Ground Six Cylinder Engines. All Parts Stores carry them.

[Brianbo]

Thanks Rich. I have two observations:
My old, analog tach/dwell meter is 12V only, so I need to get a new digital one to work with my even older car.
NOBODY at my local auto parts stores know what a tach/dwell meter is! It was hanging on the peg behind them!!
I just got blank stares. One person thought they are for some old cars🤔
I like to support local, even if they are a chain, but best price and info is on Amazon🤨

[nvonada]

Are you sure your meter is 12V only? Most use an internal battery to power the meter so it stays accurate during RPM changes. Those batteries could be dead. I suppose some meters may not trigger properly on the 6V points but that seems odd. I have an old one and new one and both work fine on 6V systems.

[duncan1951]

As far as the timing light goes just hook light leads up to a 12 volt battery then put induction clamp on number one cylinder - will work fine.

[nvonada]

My timing light actually works OK on 6V. Dim, but usable if it is not too sunny outside. Worth a try...

[Speedster#201]

Glad I found this thread. Missing piece for me is what side of the coil to put the dwell clamp on when using an external 12V battery on a 6V+ system? Would it be the + side (reverse of directions given for use on a 12V system)? Thanks!

[PackardV8]

As far as the timing light goes just hook light leads up to a 12 volt battery then put induction clamp on number one cylinder - will work fine.

If using an external 12-volt battery to power a timing light, use an alligator clip jumper to the battery. If the battery isn't grounded to the car, be careful not to touch any part of the car; the full spark plug voltage will jump through you. Ask me how I know ;>)

jack vines

[duncan1951]

never had any problem with this -
maybe waking up in the corner of the shop may explain :-)

[Speedster#201]

jack -- sounds like an altogether unpleasant scenario... in order to avoid that, clarifying questions:
"alligator clip to the battery" -- which battery and where does the other end go?
do you know where the dwell clip from my timing light would go on the 6V+ vehicle?

feel like i should diagram this to be 100% sure.

thanks!

[christophe]

The dwell meter is to be connected to the side of the coil linked to the distributor. + side in your case assuming the coil was not hooked backwards, which I often saw.

[StudeRich]

James; On the Dwell Meter Connection, the Original question:

The usually Green Distributor pickup Lead, has to go to the Dist. Terminal or the Positive (Ground) Coil small Terminal.
I would try the Car's Battery first. for the Timing Light connection.

[Speedster#201]

christophe -- thanks, didn't know that could even be a thing...
StudeRich -- I like the idea -- don't suppose it could hurt the timing light itself due to lower voltage -- the directions explicitly state that it is for 12V - .... but I'll give it a try.

FWIW, I decided to completely start over in the artistry that is timing; in order...
Set cyl Home to TDC
Rotated distributor so points are "wide open" -- at highest point on cam
Confirmed/reset point gap
Confirmed vacuum advance/spark modifier works -- hand vacuum gauge comes tomorrow so I'll be able to put numbers to it
Rotated distributor back so that "points just start to open" per shop manual
Now I will attempt to put the timing light on it while also measuring vacuum; dial in the carb to smooth idle/highest vacuum; then rotate distributor as needed to further smooth out idle and best throttle response.
What am I missing?

[Speedster#201]

Anxiety strikes -- please help!
Getting ready to hook the timing light up, I noticed that the NEG post on my coil goes to the Distributor block... is the coil polarity agnostic? Should I switch it? As christophe points out, it may be backwards....
And, does it matter which clamps from the timing light go to which posts on the battery? Black clamp to NEG post and Red clamp to POS (ground) post? OR should I cross them?

Thanks for the help!

[StudeRich]

I THOUGHT we covered that, in Post # 11 !

[christophe]

The polarity at the coil MUST respect the polarity of the battery or you'll get bad performance from the coil. Respect the polarity as well to hook the timing light (red on +, black on -). Setting the gap at the points is to be done when the engine is at the ignition point, not at TDC, but it is not critical as you'll adjust it with the timing light (with the vacuum line going to the carb disconnected and plugged). A 0,50 mm gap should put you in the 37-41 degree range.

[Speedster#201]

thanks for confirming, christophe -- after 10 years with the current +/- set-up, I'll definitely re-orient the coil (aftermarket) this weekend.

The test drive tonight with all fine tunings including your suggestion of increasing point gap from factory .33mm/.013" helped considerably. I feel like the final step will be in finding where my carb/intake leak is -- manifold vacuum is incredibly low at idle. Thanks again.