ignition coil mounting

[TED HEINRITZ]

I just read somewhere on the MSD info that a coil should be mounted vertically with the wiring at the top.

But I have seen many coils mounted horizontal.

So should it really matter, is it more critical when using a MSD spark box? Is the MSD coil more reliable than using one of the compatible coils that are listed?

Or did I just have a odd failure... I had been using a MSD 6AL with a Accel coil, and the coil failed. Bought a MSD coil and it then work fine again.

 

[Matt Blehm]

The issue with the MSD coils is that they're filled with oil for cooling/insulation purposes. mounting them sideways moves the air gap to the side, exposing a small part of whatever wiring coil is inside.

In my RX7, I have a pair of the oil-filled blaster coils mounted in the stock location, which is sideways. one of them was dead when I put the car together (after sitting 5+ years), but the replacements have been going fine for a whopping year now with no new failures.
They are driven from the stock distributor with no additional boxes or widgets..

 

[TED HEINRITZ]

I did a little more research;

Seems that most coils should be mounted vertical, most are oil filled and could more easily fail if mounted horizontally.

MSD does make a high vibration coil that can be mounted in any position. Of course the coil doesn't vibrate, but it is designed to tolerate vibration. With the rough service of a typical race car, that coil might be a better choice.

I had a second accel coil, and it would start with that one, but not really run.

Picked up the MSD coil and made the race. They actually had that at the advance auto parts store.