As the title says.
I found this and the instructions say that if the red lead is connected to the block of the engine, it should work.
https://actron.com/content/advanced-timing-light

I have an old "Sun" model, but I can't adjust the advance with it, it's just a simple strobe light.

I would like a digital one, but those are all solid state and so far I can't find anyone who has tried using an all digital type on a positive earth car.
The one in the link is an analog dial type.

Any input here would be much appreciated.

 

A 12 volt dc. timming light will work as long as you have the polarity correct, in your case if you have a pos. ground car, attach the pos. (red?) lead to the eng. ( or other body ground) and the neg (blk?) lead to a powered (hot) terminal . If your battery is in the eng. compartment, connect the leads directly to it (pos. to pos., neg. to neg.)

 

Thanks for the answer, but that much I understand. The problem is a variable advance digital timing light doesn't work _ at least the one I got from Lordco Auto supply _ the one in my link works, but it's analog.
Even correctly getting the polarity right, the light just flickered.
I was hoping that someone here had used one and would tell me what the brand was.
I guess I'll just have to find out for myself.

 

I would first determine if the light is defective (try it on another eng, car, lawnmower, etc.). If the light is ok the next thing to try is to [1] locate the pick-up in a different position on the plug wire, [2] keep it away from the other wires, [3] flip the direction of the pick-up, [4] try a new resister plug wire. Do you have a stock points/condenser/coil ignition system, or other?

 

Yup...
Lights not defective, works on my Mazda truck _ solid wires with resistor caps and non resister plugs (resister caps are 5K ohms) _ electron ignition in the Mazda of course.

1) No difference in placing the pick-up in a different position.
2) Kept it away from other wires.
3) Flipped the pick in the other direction (one of the first things I tried)
4) Not running resister wires on anything
It shouldn't matter if it's points or electronic _ I'm pretty much satisfied that the light doesn't like positive ground.
I could have tried hooking up an external power source, like a spare battery or even a battery charger, but it's too late now.

Since no one here seems to use a timing light on a positive ground car, I'll just have to see for my self.

Here's an answer that I got from Bosch with their digital light, the answer is inconclusive.

The CP7529 is only designed to work with negative ground systems and was never tested to work with positive ground systems. It may work by using a separate battery and grounding the negative pole of the battery/tool to the chassis.

I also have a confession, the light is not for my Jag, but for my Bentley _ it has only one timing mark and that is TDC and noting else.
I thought I would get the best help here.

 

The alternative might be to do it the old fashioned way and scribe the balancer with the timing marks.

 

In most cases that would be possible, but on the Bentley the balancer is all encased inside an aluminum cover _ that leaves the fly wheel which is impossible to get at.
I suppose I could simply mark the pulley at the end of the crank shaft, but even that is not very accessible.
I found a Rolls Bentley forum to post at so maybe someone over there can help.
If I find a solution for a light, I'll post back here.

 

Do not know why it would matter, but in reading the pdf manual, page 24,
https://actron.com/sites/default/fil...lish_16313.pdf
... you are to use a "resistive" wire!

 

Just went and bought this cheap one at Adams Tarp and Tools.
Trisco Technology Corp.
Although the one I have is a TA-2200 _ made of plastic, but it get the job done and works with positive ground.
It's mind blowing the price difference I found between things for the same product.
OTC makes one for around 164.00$ from Amazon _ the same one is found at Acklands-Granger for almost 500.00$ !!!

Everything is made in China or Taiwan, and if something goes wrong, you're expected to throw it away and get anew one.
The Trisco has parts availability _ the light light burns out in them _ it's quite common _ even on the most expensive.

 

I have been using timing lights on positive ground cars for 50 yrs. Never had a problem. I have an old Sears/Craftsman model, a Matco, a Snap-on, and a Western Auto(old) light. Also use an old model engine diagnostics from Sears for ignition dwell and etc. Used a Snap-on diagnostics in service shop, all were good on positive ground. Recheck how you do your connections and #1 cylinder at rear of engine (firewall) and timing thru hole in bellhousing on some, or make a pointer in front on damper after lining engine up to top dead center and go from there. if my one eyed friend with no mechanical experience can do it with a phone call, you can too.

 

In post 7 I confessed it is for my Bentley _ only has a timing mark for TDC and nothing else. The dampener is inaccessible _ thanks for you reply though.

The Innova timing light from Lordco clearly states in their FAQ that it will not work on positive ground cars _ found this out after the fact.
And it doesn't work, it just flickers like a fluorescent tube that's just about to fail _ the flicking doesn't correlate when number 1 fires at all.

The cheap one from Trisco works well enough, it's not digital, but it gets the job done.