I prefer an unlimited coil, simply like the option to check tune while not in the cut.
Not here to debate that.
A while back I played around fitting up alternative coils on my Smurf 84/6401, the 272 coil works fine but I was looking for something that would be a direct swap.
No such luck but did find a couple readily available types I had on hand that mounted with very little modification and with no need to swap out to the dolmar core.
First was from an 025, a bunch of the small stihls like 018's also use this or similar, only needed a notch filed in next to the original outside mounting hole to fit up.
The plug wire is located in a good useable spot but unfortunately is permanently affixed in place. Not difficult to dig the wires insulation out from around the conductor, then just stuff the dolmar wire into the cavity. The 025 wire goes almost all the way to the bottom of the coil, so theres plenty of depth for a solid connection.
Or just graft the two wires together.
I wasn't leaving this coil in permanently so just to try it out, put the dolmar wire in the spark plug boot and was able to route the 025 coil wire around and about so to still allow the starter cover to fit over it all.
Another somewhat less common coil that fits up is one from a bg55/85 blower, still readily available used on feepay or as aftermarket for about $14. I found a used one for $9 that I got for a blower and happened to be sitting on the bench while I had the Smurf apart.
A little bit of elongating of the lower mounting hole was about all it took to get a decent fit. Small chain file is about the right size for this task.
Same issue with the non removable plug wire unfortunately, still in a good location though.
Timed it the same way as the 025 and again ran fine. Much shorter plug wire so easier than the 025 coil to route without cutting the wire/boot off.
You do still need to grind/file the key off the flywheel, the timing is pretty far off from the original coil, seems dolmar has their own scheme that deviates from typical convention.
Somewhere here or over on AS I ran across a nice technical drawing sort of pic that showed an easy way to time a 272 coil conversion and worked fine here on the first try.
No degree wheel or other timing method needed.
Saw would tune to 14.3k with either coil no problem.
With piston at tdc, the trailing edge of the flywheel magnet block gets lined up with the trailing edge of the leading coil leg as can be seen in the bg55 coil pic.
Sooner or later when I get around to modding the saw I'll play around with moving the timing a bit.
