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 Gapping improvement

 Created by: Air2air
Orig. Posting Date User Name Edit Date
Aug 24, 2014 10:59AM Air2air Edited: Aug 24, 2014 11:01AM 
Aug 23, 2014 01:10PM nkerr  
Aug 23, 2014 12:08PM Cup Cake Edited: Aug 23, 2014 12:10PM 
Aug 23, 2014 11:17AM Air2air Edited: Aug 24, 2014 10:42AM 
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 Posted: Aug 24, 2014 10:59AM
 Edited:  Aug 24, 2014 11:01AM
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Quote:
Originally Posted by Cup Cake

Stock gap is 0.025 AFAIK. If your motor works with 0.044 you could probably retard the timing some.


Larry, yes I've heard that too.  What is the relationship there between timing and gap? Is the assumption that the burn will always be faster?

Norm I got the Pertronix dizzy and the humongous Flamethrower 60kv coil a few months ago.  It was an improvement over the gold coil and Pertronix Ignitor 1 that was rattling around in my old 25D.  But not a $500 improvement.

But after adding an extra 50% or so the gaps, man that thing opened up.  Yesterday I was idling at 1200 instead of 1000.  It is definitely pulling harder and really smooth, just like a real car.   The kind of improvement we're used to spending several hundred bucks for.

After putting on 300 mi yesterday the plugs are nice and brownish, no more fuel smell.

 Posted: Aug 23, 2014 01:10PM
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a large gap and a high voltage coil are usually used to get a very lean mixture to burn

In very general terms, the A series head has such excellent burn characteristics (thanks to Harry Weslake), and tends to run a tad rich with SUs (compared with modern, fuel injected cars), that the difference in power from a stock ignition to a high powered one is often not all that much.

So, it is interesting to hear how much increasing the gap has improved your motor, I am glad to hear it!

Norm

 Posted: Aug 23, 2014 12:08PM
 Edited:  Aug 23, 2014 12:10PM
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Stock gap is 0.025 AFAIK. If your motor works with 0.044 you could probably retard the timing some.

The power of accurate observation is commonly called cynicism by those who have not got it. G.B.S. Sarcasm is the lowest form of wit. Oscar Wilde

//www.cupcakecooper.ca/

 Posted: Aug 23, 2014 11:17AM
 Edited:  Aug 24, 2014 10:42AM
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Noticed quite a performance difference opening up the plug gaps by 0.010" since I put on a larger 60kv coil.  If you guys agree the stock gap is 0.034" depending on where you read it.  Looking at other classic car forums this appears to have been the default through the sixties for many American cars as well.

Pertronix plays it safe and will only suggest going 0.005" over your stock setting, you have to read what other guys are doing to get the nitty gritty.  

I'm at 0.044 now, it idles much better, it feels faster and there is a lot less unburned gas smell.  However I do have a pretty huge Flamethrower coil so perhaps trying 0.005 first is safer if you want to fool with this.