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Ignition Timing

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eric ANDRE

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Hello, I would like to know how to regulate and do the timing of the ignition for a Healey 100/4. Where is/are the markers? Thank you.
 
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There should be an embossed arrow as shown in the picture on the timing cover. On the crank pulley there should at least be a notch as shown for top dead center. If you just have the single notch on the pulley you'll need to make your own marks for what ever timing you want based off the one notch. Some pulleys have had marks added and they may not be labeled. You should be able to figure it out by making a degree wheel taped to the pulley. A little geometry is the easiest way to add more degree marks.
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I suggest you get an advance meter; aka timing light with dial advance. Turn the dial until the pointer and notch line up, read the number off the meter (or set the number of degrees you want and turn the distributor). The advantage with these devices is you can set to the degree, and also measure total advance (I don't have that number handy for a 100, should be 30deg at 3,000RPM plus or minus). If your car is still positive ground; try to find one with a plastic case; otherwise the case will likely be hot/grounded (you can use one, but if you touch metal on the car you'll have a welder).

Do you have an equivalent to Harbor Freight in France?
www.harborfreight.com

Xenon Advance Timing Light

Amazing deals on this Xenon Advance Timing Light at Harbor Freight. Quality tools & low prices.
www.harborfreight.com www.harborfreight.com
 
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I have a 35 year old timing light with no advance feature. I keep hoping it will fail so I can go buy a new fancy one but dang it, it just keeps on working. Had I been fully in the 21st century I would have suggested that as opposed to fiddling with measuring for marks.
 
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What's the difference with bumblebee wires and stock 7mm stranded copper core (besides marketing/$$$)? I've never had an issue using an advance meter--two of them so far--with the stock wires. Maybe lack of shielding overloads the inductive pickup modern timing lights use?
 
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The bumblebee wires are stranded tinned copper or steel. Other wires are usually wound carbon resistance wire. I have to substitute a normal resistance wire on #1 to use an advance meter.
 
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Both my advance meters have worked fine on my stock 7mm stranded copper wire--as I suspected, the bumblebees are just marketing--so it's probably random chance (secondary wires are high voltage but low current; a couple strands would likely carry the current). If a light or meter won't work with stranded wires it's probably because the RFI overloads the inductive pickup.

Note Pertronix says not to use its units with stranded copper wires, but I've gotten well over 100K on a Pertronix with them.
 
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I think Pertronix is concerned about RFI with copper wires. I have a Crane system so RFI doesn't bother it. Maybe it's the 60K volts in the Bumblebees that causes the interference.
 
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Bob_Spidell said:
What's the difference with bumblebee wires and stock 7mm stranded copper core (besides marketing/$$$)? I've never had an issue using an advance meter--two of them so far--with the stock wires. Maybe lack of shielding overloads the inductive pickup modern timing lights use?
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Never had a problem with advance and timing lights,got both, used with bumble yellow wires
 
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I have a 3000 so don’t know the timing for the 4 cyl car. Somewhere in the spec or in written work there are inch equvilent to degrees written. With the 6 cyl cars 1/2” is about 8 or 10 degrees. 5/8s maybe 12 degrees. I have run my BJ7 between 1/2 to 3/4 inch before top dead center for 20 years. You can just eyeball the distance. Put the timing light on approx 1/2 or 5/8 inch BTDC and you got it. Take it for a run. If it seems a little sluggish bump the timing a 1/16 inch. Keep bumping the timing till it doesn’t feel any quicker or till it pings. If it pings then back it off 1/16th inch. But 1/2 to 5/8 inch has always worked for me. If the 100 pulley is the same diameter as the 3000 then these demensions will work. You don’t need any marks.
 
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John Turney said:
I think Pertronix is concerned about RFI with copper wires. I have a Crane system so RFI doesn't bother it. Maybe it's the 60K volts in the Bumblebees that causes the interference.
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Who makes a 60KV coil? Even the Pertronix and Lucas Sport type only claim 40KV. I did see some ballasted that claim 60KV.
 
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