Soark Plug Gap

[xsteamer]

Hey guys, I just cleaned and regapped my spark plugs. Specs say between .024 and .026, so I set them at .025. But I seem to remember reading somewhere that the gap can or should be greater with electronic ignition, which I have.
Anyone comment?

 

[Nunyas]

I have a Crane XR-700 electronic iggy. I set my plugs to 0.32.

 

[tony barnhill]

/bcforum/images/%%GRAEMLIN_URL%%/lol.gif Love the tag line on your sig, Rob...you should send it to Carroll Shelby!!

 

[Steve_S]

That really is a great sig line. It's a keeper! LOL!

As far as spark gap goes, the more power you put to the plugs, the wider the gap can be. The wider the gap, the bigger spark, and the more efficient burn. Too wide a gap for the voltage and performance will suffer. If it's a good EI unit and is functioning properly, you can safely go wider. Start with .028" and see how it goes.

You don't have to widen the gap, and leaving it narrow will not harm anything. Better how it is than too wide.

 

[xsteamer]

Thanks guys and yes I have a Crane XR-700 too.....

 

[DrEntropy]

0.028"~0.032" then, yup.

 

[Nunyas]

err ... yeah... 0.032" is what I run... .32 would be a bit on the ~large~ side... /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

I got tired of the Darkness tag line, and wanted something "different" /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[DrEntropy]

We knew what ya meant, Rob. Plug gap, not caliber. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[Nunyas]

lol

 

[xsteamer]

Re: Spark Plug Gap

Well folks, Went on the run Sunday and the B seemed to be struggling a bit because I really didn't want to engage the overdrive. Reason being once the car warms up and I engage overdrive I seem to loose reverse gear. Anyhow, The plugs got sooty so I regapped them .032 to .035. I will test run after the rain goes.

 

[tony barnhill]

Re: Spark Plug Gap

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I engage overdrive I seem to loose reverse gear[/QUOTE]

What do you mean by that statement?

Your OD should engage when you're over 45mph (I think that's the speed) in 4th gear by just pushing the stal switch. There's a switch that won't allow the OD to work in reverse but it should be deactivating your OD when you go to reverse gear, not affect your reverse gear.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]The plugs got sooty [/QUOTE]

Carbs too rich?

 

[Keoke]

Re: Spark Plug Gap

Well folks, Went on the run Sunday and the B seemed to be struggling a bit because I really didn't want to engage the overdrive. Reason being once the car warms up and I engage overdrive I seem to loose reverse gear.
-----------Sound like you have very smart overdrive. It knows its not good to back up when its engaged. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

Anyhow, The plugs got sooty so I regapped them .032 to .035. I will test run after the rain goes.

Also sounds like you might be running a tad rich if the plugs are sooty and she be struggling a bit too.---Fwiw--Keoke-- /bcforum/images/%%GRAEMLIN_URL%%/yesnod.gif

 

[xsteamer]

Re: Spark Plug Gap

Tony, What I mean is that the reverse gear intermittently doesn't work. It just sits there and revs. I believe it happens more often after the car is warm and I have used the OD. Similar thing happens when down shifting into 2nd there is no noticeable decrease in speed or revs.

 

[xsteamer]

Re: Spark Plug Gap

Tony/Keoke,
I believe I have an after market fuel pump because it never quits ticking (Timex) so I bought a fuel regulator after the SU rebuild kit was installed because I was running too rich. I later bought a downdraft weber (which requires being used with a regulator). I probably need to fine tune reg a little more.

 

[Dave Russell]

A couple of things to consider.
The LBC's have relatively small cap diameter, plug wire electrode spacing, rotor length/height/insulation.

Increases in plug gap require higher voltages, better rotor insulation, larger plug wire electrode spacing. Higher voltages with the stock setup are more likely to cause cross fire between plugs, & rotor insulation break down.

Note that more modern distributors, designed for higher voltages-plug gaps, have larger diameter caps & taller rotors with the accompanying greater insulation & air gap length between plug terminals & between rotor top contact & shaft.

The weak point on small Lucas distributors is the small amount of insulation between the rotor's center electrode & the shaft underneath. Increasing the plug gap requires higher firing voltage which puts even more stress on the marginal rotor design.

Lastly, if the plug gaps are set at the maximum that the system will fire, there is no margin for the increased plug gap as the plug wears. Constant plug regapping will be required to keep things working.
D