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Author Topic:   Spark Plug Gap
chief4car
Member
posted July 10, 2002 09:34 PM
What would be a good plug gap for a 12.8 to 1 406 with an MSD ignition. We run Champion Race plugs V55C or V57C on Alcohol.

Thanks
Jim Cleaver Jr
Cleaver Racing Inc


birdcage
Member
posted July 10, 2002 10:27 PM
I used to spend a whole lot of time diddling with plug gaps, until I asked a Winston Cup engine builder what he recommended. He said; "Take them out of the box, look at them to make sure they have not been dropped, and put them in. You will cause more trouble by trying to change the gap than any gain will be worth." My plug changes now take a whole lot less time. On the plugs you mention, out of the box gap is about .024 or so, and on most RACING plugs(Autolite and Champion) the gaps are very consistant. Others may howl, as did my crew chief at first, but he eventually came around and this way has worked quite well for us. I should also say that I don't keep plugs in an engine real long like some guys do(a holdover from my 2 stroke days!)


chief4car
Member
posted July 11, 2002 09:26 AM
Thanks for the replies guys.
Monster your right about the gap of the plugs out of the box. We have been gapping them at .025 and hardly any change is needed on out of the box plugs. I was just wondering if I was leaving anything on the table with the plug gap.

I think i will stick with what we have been doing it seems to be working.

Thanks
Jim Cleaver
Cleaver Racing Inc


AIRFLOWDESIGN
Member
posted July 22, 2002 11:04 PM
Get yourself a medical inspection light like what Doctors use to check out your ears. You can get one at http:///HardcoreParts.com plus Moroso makes one too.
When you look at the plugs look deep down into the porcelain insulator and at the bottom you should see a tan ring around the porcelain. Now the higher it is up the porcelain the richer the engine is running.

Also look at the ground strap and it should be a light blue color. When this blue color gets close to the body the plug is running hotter. I hope this helps. Ron Melville www.airflowdesign.com



dirtracer14
Member
posted July 22, 2002 11:33 PM
For the plug gap we call it "box Gap" works for me .


crewcf
Member
posted July 23, 2002 10:32 AM
always go on the narrow side for gap wide gaps are great in a perfect environment start adding,high cyl press.,wet dirt,and the worst thing glycol(a conductor)then things go wrong also carefully look at the ground electrode you will see an temp line if heat range is correct the line should be at the bend richer to center leaner to body try this it is much easyer than looking down insulators


AC156
Member
posted July 31, 2002 04:11 PM
would too wide of a plug gap cause an engine to miss fire at high rpm?


birdcage
Member
posted August 01, 2002 12:54 AM
YES ,it can but you may not here it and power will drop off severely.

[This message has been edited by birdcage (edited August 01, 2002).]

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