Advance Timing Light

[Rob Glasgow]

I installed a rebuilt distributor on my BT7 and set the timing by ear. The car runs very well with what I estimate 10 degrees BTDC at 800 RPM. Wanting to verify my setting, I purchased an Advance Timing light from Harbor Freight (item 40963).
I had borrowed and used an advance unit 8 years ago so I thought I understood how they were supposed to work. Set the advance you want on the dial, point the gun at the timing marks and if you've got the distributor in the correct position, the light will flash and show both the fixed pointer and the mark on the pulley lined up next to each other. In other words, the light will flash a little after TDC so the marks line up and you don't have to guess.
I tried the new HF unit and found that no mater where I set or moved the dial on the gun, the timing marks did not move when the light flashed. It acted like a standard non-advance light like we used to use 40 years ago. I thought maybe I had a defective light so returned it to HF and got another. Same results. No matter where I moved the dial (0 to 60 degrees) the light flashed in the same spot and the marks did not move in relation to any dial adjustment.
I am wrong in my assumption that the marking should move as I rotate the dial? If I set the dial to 60 degrees BTDC, then with my current setting, the marks would appear to be retarded by about 50 degrees.
BTW, the light shows my pulley mark about 1/2" before the fixed pointer at 800 RPM so I think my timing is in the ball park. Also, I live in a small town and don't have many options for better quality tools, but in all fairness I have been satisfied with most of what I've purchased from HF.

What as I missing? The package says "60 degree dial makes it easier to read and adjust timing advance". If the dial doesn't control the amount of advance, I can't imaging what it's for.

 

[Keoke]

ROB:

You missed going to sears and getting a good timing light.:glee:

 

[Rob Glasgow]

Keoke, you're prolly right. After looking at several you-tube videos and the reviews of the HF unit, it's apparent I got two defective lights. I don't think I'll try number 3, but take your advice and get one from Sears.

 

[DerekJ]

I had the same issue with a timing light I bought here in the UK. I filed it in the draw marked 'Garbage'. I go to a rolling round once a year to ensure the Webers and timing are exactly how they should be.

 

[John Turney]

Rob,

Are you using Bumble-Bee wires? I had the same problem with several timing lights, including the Sears one that Keoke recommends, until I changed the plug wire on #1 to a regular wire. I'm also running about 50,000 volts, and it just overwhelms the adjustable timing lights.

 

[Rob Glasgow]

John, I am using a set of wires from NAPA. They are stranded wire but I don't think they are anything special. I just think the timing light is not very well build. Several reviews mentioned the same issue, but many of the negative reviews alswo mention the bulb failed quickly so I don't think it's worth it, no matter how inexpensive it is.

 

[Martinld123]

I went through same problem with the one I bought at an auto parts store. I had bumblebee wire on all four plug wires and it would not read right so I was told to replace number one wire with resistive wire and then it worked. There is no resistance on plain copper wire like Bumblebee wire. Marty

 

[Rob Glasgow]

Well perhaps there was no problem with the HF units after all. Maybe with other types of wires they may have worked.
I am a bit confused since the units had no trouble picking up the spark signal from the wire. I would think the internals of the light would just be responsible for adjusting the moment at which the light flashed based on where the dial was set. Anybody else out there ever had success with this HF unit?

 

[Keoke]

I went thought same problem with the one I bought at an auto parts store. I had bumble bee wire on all four plug wires and it would not read right so I was told to replace number one wire with resistive wire and then it worked. Marty

This is possible if you have a noisy ignition system and the light is encased in plastic like my Snap On but the Sears unit has a metal case

 

[GregW]

Some multi-spark ignition systems will confound an adjustable timing light. I had to use an basic timing light after confirming Innova, who made my advanceable timing light.

 

[Rob Glasgow]

In looking at old posts about issues with advance timing lights and solid core spark plug wires, I noticed folks who used old Sears metal timing lights did not experience the problems that modern units have. It reminded me that when I borrowed my friends light several years ago to set the timing, it was and old Sears metal unit. I had the same spark plug wires That I have now. So some times old is better than new....
unfortunately, my friend moved out of stare and took his light with him.

 

[John Turney]

Yes, the new Sears lights have a plastic case. My old Sears one isn't adjustable. Maybe a bit of tin foil around the light would help?