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Unleaded Fuel and Ignition Timing

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Dace1953

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Hi guys,
I’m returning to the setting of my 1960 BN7 ignition timing.
I set the static timing and the car runs, but I feel it could be better.
The plug gaps are at .035” and the points gap .015”. I now have the use of a Gunson timing light, but am confused by two of the settings- does the distributor vacuum advance pipe need to be disconnected?
The car was converted to run on unleaded fuel; does this affect the timing light setting?
I’m using an engine idle speed of 800 RPM with the engine at operating temperature.
Any advice would be most welcome, before I dive in and screw things up!
Regards
Dace
 
Dace1953 said:
Hi guys,
I’m returning to the setting of my 1960 BN7 ignition timing.
I set the static timing and the car runs, but I feel it could be better.
The plug gaps are at .035” and the points gap .015”. I now have the use of a Gunson timing light, but am confused by two of the settings- does the distributor vacuum advance pipe need to be disconnected?
The car was converted to run on unleaded fuel; does this affect the timing light setting?
I’m using an engine idle speed of 800 RPM with the engine at operating temperature.
Any advice would be most welcome, before I dive in and screw things up!
Regards
Dace
Click to expand...
Welcome to the BCF.
Yes, the vacuum advance pipe should be disconnected.
Conversion to running on non-leaded fuel should not affect timing unless the head or block were shaved so the compression ratio is increased.
You can make minor adjustments with the knob on the vacuum advance.
 
There are a couple of ways to set your timing in order to get optimal power. The easiest way is to loosen the clamp on your distributor and turn it a small amount to bring your RPMs up a bit. Tightened the clamp and drive the car. Hard. Get on a hill and put it in fourth gear and floor it. If your engine doesn't ping, or knock, advance your distributor a bit more. Keep doing it until your engine knocks and then back it off. This is how you get perfect timing for your specific engine.
 
Since the amount of total advance (combined centrifugal and vacuum) are not easily adjusted without delving into the distributor's innards I merely concern myself with total advance at around 3000 rpm's, shooting for around 34-35 degrees. I then follow a process more or less along the lines that Richard suggests. Keep an eye on the temperature gauge.
 
Per the manual, the vacuum advance line at whichever carb--2 or 3?--it is affixed to should be disconnected and the hole on the carb capped (though I've not found it to make much difference). Again per the manual, timing should be set at 600RPM, but I doubt many owners run that slow. Easiest technique is to use an advance meter--they're cheap enough these days--and set as Michael suggests (35deg BTDC at 3K RPM). Note the octane rating of your preferred fuel will have an effect (I believe the UK uses 'reaearch' method?).

I think your plug gaps may be a bit wide for a car running on points. Which/whose plugs are you running? What kind of secondary wires? Do you have ethanol in your gas? If so, a slightly richer setting might help.
 
Or you can just do it without a light using this method
 

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Or you can do this to get it the tune spot on.....

'57 Dyno Rear.jpg


Dyno Tuning.jpg
 
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