PlaneKrazee

My Feedback: (14)

What is the proper gap for a cm-6 plug?

w8ye

My Feedback: (16)

.4 mm - .6 mm or .015" - .024"

Probably run best at .020"

Truckracer

My Feedback: (19)

TKG, Terry from CH ignitions usually suggests using a #11 X-acto blade for a feeler gauge on the CM-6. Thats .020" to .021" on the blades I have measured. Simple enough and you don't have to look far for a tool. They come out of the box at .018" and both Ralph and TOM have suggested the gap really isn't very critical. I just took a CM-6 out of a DA-50 that had been in there untouched for 3 years and it had worn to a gap of almost .030" ... was still running just fine.

pe reivers

We found that the electrodes in CM6 plugs wear faster than in other plugs. (increasing gap)
In one engine, after a few years of intensive use, the engine started cutting out unexpectedly. The plug central electrode and mass electrode were worn too much, combined with slight plug fouling down the central ceramic isolator. Changing the plug with a new one gapped to 0.5mm cured that.
I would suggest the standard 0.5mm gap, and inspect the plug at least on a yearly base.
Will post picture of mine if I can find it.

pe reivers

Here it is,
The engine has about three gallons through. Still slightly rich in it's tune, but running well.
Slightly blurry, but the onset of electrode wear can be seen already.

PlaneKrazee

My Feedback: (14)

Thank you for the replies.