Proper Plug Gap with MSD Ignition

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Sep 26, 2003 | 11:11 AM

My69

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Burning Brakes

Joined: Jul 2001

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From: CT

Proper Plug Gap with MSD Ignition

Does anyone know the proper plug gap when you run and MSD Ignition. There literature says to add .005 to .010. Does anyone have a more exact recommendation

Sep 26, 2003 | 11:17 AM

zwede

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Joined: Sep 1999

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From: Plano TX

Re: Proper Plug Gap with MSD Ignition (My69)

I read some webpage on MSD's site that said for naturally aspirated engines running up to 10:1 CR you should gap at 0.050 to 0.060.

Sep 26, 2003 | 11:18 AM

467-Ratman

Burning Brakes

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From: Bay City MI.

Re: Proper Plug Gap with MSD Ignition (My69)

In the instructions they say to gap your plugs at between .050 and 0.60, I have mine set at .050 and seems to work well. With my old GM system I used the old standard of .035 but I guess with the extra juice available from MSD you might just as well light the camp fire with a bigger flame!

Sep 26, 2003 | 10:29 PM

AlwaysWave

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From: Hoosier

Cruise-In III Veteran

Re: Proper Plug Gap with MSD Ignition (467-Ratman)

with an 8.5 compression ratio, MSD 6A, MSD Wires, and a Pertronix, and Rapid Fire plugs, I found 045 to run best.

Sep 26, 2003 | 11:12 PM

cardo0

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From: Las Vegas - Just stop perpetuating myths please.

Re: Proper Plug Gap with MSD Ignition (My69)

:nono: I can’t find his book right now but I recall old Smokey said .050” for a high voltage box and nothing to gain beyond that. Also keep all wires ½” apart minimum with that high voltage ignition. The #5 & #7 wires need separation the most (18436572) and should only cross at 90* if possible to prevent induced misfires. He talks how surprised he was to find how many pistons were destroyed by misfire when something else was blamed for it. :conehead

Sep 26, 2003 | 11:18 PM

gdh

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From: Canada

Re: Proper Plug Gap with MSD Ignition (AlwaysWave)

Quote:

with an 8.5 compression ratio, MSD 6A, MSD Wires, and a Pertronix, and Rapid Fire plugs, I found 045 to run best.

I have 10.5:1 with the same MSD6AL, MSD wires and Petronix with the accel shorty (header) plugs. I have not chenged the gap from the box setting of 35, my question is this: what difference would I feel by going to a 50 or 60 gap, would it be at the lower rpm range ie. 3500 and under. This is something I just never considered when I bought the MSD from a fellow forum member.

Sep 26, 2003 | 11:31 PM

AlwaysWave

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From: Hoosier

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Re: Proper Plug Gap with MSD Ignition (gdh)

Quote:

my question is this: what difference would I feel by going to a 50 or 60 gap, would it be at the lower rpm range ie. 3500 and under. This is something I just never considered when I bought the MSD from a fellow forum member.

At 060 my 350 had less of a torquey feel at WOT. The 0 to 80 time seemed to be more than before. Over time I gapped down to 045 and it runs pretty nice. The wider gap is supposed to help ignite the mixutre faster and better.