Hi-6 plug gap

[smac61]

OK I have searched and read until my eyes are buggin out. For those with Crane (or other ignition modules), what plug gap are you using for Autolite 25's?

 

[blown1989saleen]

use the stock gap, .052-.054

 

[STINGREY]

dude;the module dos not dictate the gap.the coil output does.what does your coil put out?

 

[Michael Yount]

Regardless of coil or module, you want to run as much gap as the ignition system will reliably support. So experiment with it - start with stock and work your way up. If you have enough energy to jump a bigger gap, that makes for a big, fat spark exposure to the mixture, and as Martha would say, that's a good thing.

 

[STINGREY]

your right ,but thats not regardless of the coil.remember the coil puts out the spark,48,000 volt coil dictates a bigger gap as opposed to the stock coil of 37 or 38.and if your running an msd unit then you can increase the gap even a bit more.

 

[Michael Yount]

You're misunderstanding my post Sting - didn't intend to imply that the coil wouldn't impact how big a gap you could run -- it will impact it. But, REGARDLESS of what your system is, run as a big a gap as your system will reliably supply. If you have more coil, that gap will be larger. The stock system/coil will support the stock gap of .054 unless you're running more compression or boost. The point is - play with it and see. You won't really hurt anything. You'll get some mis-fire when you get the gap too big -- then back it down from there.

 

[smac61]

Thanks guys! Don't know what the coil output is. It is a Crane PS-91, and all I can tell you is you don't need a dark room to find an arcing wire. Major lightning bolts! You guys ever tried cutting back the ground strap?

 

[04sleeper]

Thanks guys! Don't know what the coil output is. It is a Crane PS-91, and all I can tell you is you don't need a dark room to find an arcing wire. Major lightning bolts! You guys ever tried cutting back the ground strap?

I have always read that the stock coil is good for 50,000 volts and the stock gap being between .44-.46.?
I do have my ground straps cut back half way over the electrode. Seems to work ok.

 

[393Bird]

I am running the MSD Digital 6 Plus with there new HVC II coil on mine. Plugs gaped at .070, and work fine.

I cut the plug grd to the center of the electrode.

 

[bmorrisj]

i have a mallory hyfire, msd blaster TFI coil and MSD 8.5mm superconductors, im running a .57~.58 gap...

 

[Michael Yount]

Mild H/C/I combo; stock ignition on mine. I cut back the ground to about half way over the center electrode and run .054". Mileage/drivability/performance have remained unchanged for the last 2 1/2 years and 14K miles - no other changes other than oil/filter.