Plug gaps for MSD systems
 

Can anyone make a recommendation on the size of plug gap with this system.

I have the MSD's 6AL ignition module with their tach drive distributor and blaster 2 coil.

This is installed on my 454 running 9.5 CR with Edelbrock performer heads.

Currently I have the plugs gapped at .035" which I believe needs to increased before firing the motor for the first time.

I've read the gap can be as high as .060". Any input of what works in real life will be greatly appreciated.

Thanks
Ian

Anyone?

got the same set up a you. my ac delco rapid fire plugs are set at .045 gap, and work great..:thumbs:

Thanks, I'll give that a try tonight.

Right from my MSD 6 series manual:

Up to 10.5:1: 0.050" - 0.060"

I have the same setup as you and use .050".

To the OP: Just to cover the bases, I'd recommend doing a search of C3Performance for other threads like this. In one of them, Lars gave a great explanation as to why this big of a gap may not be as beneficial as you'd think, and might actually be detrimental. :cheers:

0.035

There's no free lunch. Your coil will put out a set amount of energy. This is roughly gap voltage x secondary current x time. If you increase the spark gap, you increase the voltage requirements to jump that gap. This reduces the amount of time that the spark is actually "lit". It would be nice to always run a large gap (more fuel molecules are lit off at the start of ignition), but there's also downsides with shooting your wad with one quick spark (spark getting blown out due to swirl turbulence). Keep the gap reasonable like the guys suggested above, and you should be fine.

I have the same system on my ZZ4 and use .045 gap.

The msd 6al is a triple strike system ,,,,,,,,,,,,,,,, firing each plug three times below 3k rpm .


Geo

I installed a full MSD system 6yrs ago and Gapped plugs @ .045 ever since.

If the system was adequate, it would light the fuel the first spark. If the first spark doesn't light things off, then the advance for that cylinder is retarded while it waits for the second (or third) spark to occur. So, the benefit of multiple sparks is what?

A complete burn.
The sparks don't take long. I will shoot off the sparks in the same amount of time as a normal spark from a single spark system.

Instead of the secondary windings of the coil multiplying 12-14 volts
with the box its multiply at least 500 volts zaps the plug very hard
and can jump a wide gap, the standard setup used a longer duration
of spark but its very weak by comparison. the box at idle speed
will strike the plugs five to six times in 20 degrees of crank rotation with very high voltage. by 3000 rpm it will strike the plug
three times in 20 degrees. even one strike higher up in rpm is still
very strong.

Define strong.

Somebody woke up on the wrong side of the bed today.

From MSD's site:

MSD 6A, PN 6200
The MSD 6A is the base model of the capacitive discharge multiple spark 6 Series design. Whether you have a powerful street machine, hard working truck or trick street rod, the powerful multiple sparks of the MSD 6A will ensure complete combustion. Benefits such as quicker ET’s, easier starting, reduced plug fouling, more power and even increased fuel economy can be expected with the 6A’s high energy multiple sparks.
Like all of the MSD 6 Series Ignitions, the 6A will work with virtually any vehicle as long as it has a 12-18 volt electrical system. It can be triggered using breaker points, a magnetic pickup or the output of an electronic amplifier. All necessary parts and wiring instructions are included.

Uhh...You Might think of it as One Long Hot Spark..MSD does it like that..

Justin,

You gave me marketing hype. I asked for engineering data. Trust me, there is a world of difference between those two items.

ps: Let's also cut the personal comments. I'm trying to have a technical discussion here. Please restrict it to that.