Plug gap setting with MSD 6 ?, Technical help and opinions please - Options

[David Mueller]

I've a '74 2.0+ runing a set of 44 Webers - MSD dissy and MSD6 control box - and I wanted some help with set up - I've been reading here about what people recommed for set-ups and I wanted some more opinions which on this site should be easy to get...

I'm running NGK BP5E S Plugs currently gapped @ 0.40 is that about right ?

Webers - 36mm venturies - F11 - 140 Mains - 200 A/C - 55 Idles Main fuel inlet needle jet is a 175 -

I've tried 50 idles any they don't work well on the fuel up here in Canada - I live in Calgary AB which is about 4500' - 6500' depending on the weather...

I've seen people saying they are runing about 12 degree initial timing with a 29 max advance timing - I haven't changed out any springs or bushings in the MSD dissy yet..Most people are running the mallory when you put int he grey/grey springs what kind of a torque curve does that give you as I can match with the springs form the MSD - is the grey/grey combo the fastest spin up / medium etc...

Any help would be appreciated...

Other info on the car if it's needed - 96mm big bore kit from EBS racing -, aux oil cooler, high output oil pump, CB perfromance hex bar linkage, MSD Blaster 2 coil with 8mm Jacobs leads,

Help anybody ?

[Joe Ricard]

My set up is near yours but leaner main gas jets. Anyway.... I set the plug gap @ .040 seems to run pretty strong. The coil is what dictates the spark power to jump the gap.

petronics flame thrower coil and Magnecore 8mm electrosport wires NGK plugs.
Mallory CD box, Compufire points trigger.

[David Mueller]

(IMG:http://www.914world.com/bbs2/html/emoticons/icon_bump.gif)

Only one opinion...that's not what I expected...

[Aaron Cox]

im running 12 initial and 29 max with a unilite. yes...grey grey springs are done advancing an 2k of rpm.

i have weber 33's also... 55 idles, 36 vents.... i forget the rest of the setup......

12 at idle is crisp and responsive......


BTW- why did you choose the MSD? (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[David Mueller]

I bought the MSD 'cause I had the MSD6A control box and it plugged right in...I wans't sure if the Mallory would have...the only pain was changing the terminal boots on the plug wires..and it's a really tight fit....

I haven't fired it up yet that's why I checking settings...the MSD has an advance bushing stop which tops it out at 29 - and fouor differnet springs - the fastest spin up is the light silver set -

I should have it up and running this weekend...finally it's been a long winter...

I installed the cooling flaps (missing when I bought the car) and theromstat...and since the tin was all off I repainted and straightened etc...rereouted all the wiring...fuel lines and now I have to go through the carb set-up again because I changed the linkage around a bit...

Other than the new Dizzy at least it was just labour not a huge sack of $$$

[ArtechnikA]

yeah - 0.040-something...

if it gets sputtery at high speeds and high load it might be too much.

i run about 0.046" with the HI-6. i'd run 0.044" except i don't have a feeler gauge that size (and all my plug-gapping gauges wimp out around 0.036") so i use the 0.022" and the 0.024" that are right next to each other... i'm also running Denso fine-wire Iridium plugs and the Crane MX-92 pulse transformer...

motor's getting tired so it rarely sees more than 6500 these days...

[Mueller]

just remember that with electronics, the "spark" will occur at the path of least resistance, so the bigger the gap, the better your wires, cap and everything else has to be

in other words if you get a nice spark at .040" with crappy wires and then set the gap to .060" with the same wires, the new gap might be too much, so the 20K volts will try to find an easier path, which could be thru the cover of the wire.

It appears you have all brand new items, so you should be okay.

in theory, you want the largest gap possible that will still ignite under pressure, a small gap is easy for the spark to jump, a larger gap gets the spark excited and it has to "explode" more to get across the gap.....also, a higher compression engine will have more cylinder pressure and the gap might have to be smaller....

I'd start at the .040" or so and test the car out, make sure you put a good load on it, such as hill....then you can slowly increase the gap until you feel that the car is not responding