031 Flywheels

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PogoInTheWoods

Don't forget about the alligators...
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Does anyone have pics of both electronic and points 031 flywheels for comparison of key way location relative to magnet position..., and perhaps actual measurements of the differences for converting to an electronic module using a points flywheel? Lakeside did this some time ago, but it was pre-hack and the pics and illustrations are long gone.

I've read for days about everyone's approach to advancing (and even retarding?) the points flywheel position to accommodate a chip conversion. Seems like the only universally accepted solution that works every time is to swap the flywheel to an electronic ignition flywheel..., which presumably also means having a points flywheel positioned exactly as an electronic one (timing-wise) by removing the key and rotating it the correct amount in the correct direction would achieve the same result.

I realize there have been many many posts by many many folks using many different electronic triggers that flat out contradict each other in every conceivable way. I also know (or think I know) that the one constant among all the other variables is where the coil reaches maximum voltage relative to the flywheel magnet position which is what activates the trigger mechanism itself one way or another..., be it a points or electronic ignition.

Some chips are said to provide their own timing advance without having to advance the position of the flywheel itself. I frankly view this to be impossible since the magnets would need to have passed the coil to generate the voltage required for the chip to do anything in the first place, let alone provide a spark sometime in the 'future'. Many modern coils have a built in retard for easier starting, then advance timing for increased performance as rpm's increase, but I'm not aware of any trigger mechanism that can 'advance' timing before it's even triggered.

There are also the occasional polarity issues. The chips with the dual terminals can be easily reversed and the single terminal versions can as well. Not quite as easy, but still do-able. Trial and error there.

Truth be told, I'm usually a "keep the points ignition intact/original" kind o' guy when it's feasible/possible and have a few WIMA chips on hand as capacitor replacements specifically for 031's. That said, ya still need a good set of points for a WIMA solution and the OEM points sets available from Stihl these days are evidently junk in both quality and fitment according to the only two Stihl dealers/mechanics in my area whose opinion I'd give two cents for. Along with that, the OEM condenser/capacitor replacement available these days pretty much needs to be externally mounted anyway since the fit under the flywheel is very tight and the bracket required to mount it is NLA. With all that considered, converting to a chip is cheaper, faster, and easier than staying with points on an 031..., providing you can somehow get the timing right one way or another.

30 degrees 'advance' has been tossed around as what is required for a points flywheel when used with a chip. My question there is, "compared to what"? According to the specs, the timing advance of a points 031 is 2.0 ~ 2.5mm BTDC of piston movement which translates into 25 degrees of timing advance at 8Krpm if I'm interpreting the spec correctly - which is presumably achieved (or assisted) by some level of advance designed into the coil itself. That certainly doesn't do much to establish how much adjustment of the flywheel position is required to achieve that same spec with a chip, only how much crank deviation relative to TDC in mm's (as measured with a dial indicator) achieves that spec in a points setup.

Now I realize that I'm probably overthinking this and should probably just keep taking the damned tank off and moving the flywheel around with no rhyme or reason until I get lucky and the saw runs right and the muffler doesn't glow, but call me curious. LOL BTW, the reason for the 'glowing muffler' condition is a flywheel moved so far out of time that combustion occurs while the exhaust port is actually open -- which essentially makes the muffler itself part of the combustion chamber.

So anyway..., I'd just like to know a precise and repeatable way to do this conversion with any one of the chips available today..., typically a dual terminal MegaFire/NovaII or single terminal Rotary. Pics and measurements between a points and electronic flywheel seem to be the next best thing to gathering up all the various chips and experimenting with a timing light and tach and different points flywheel positions to otherwise arrive any useful conclusions.

And @hotshot, you certainly seem to be quite well versed on the subject with what I personally consider some of the most logical, practical, and informed approaches that I've read so far. Any additional comments and/or observations here would be more than welcomed..., especially if you happen to have the old Lakeside stuff or some secret timing numbers stashed away somewhere.

TIA for any/all constructive input from anyone with practical experience on the matter. Would be nice to have a reasonably short thread that finally conquered this whole subject once and for all.

Yeah, I know. Wishful thinking. LOL
 
Forgot to add this link as one of the better posts on the subject. Long story, but some good stuff if you can get through it. Seems like a pretty definitive way to do it from scratch..., if you have the manual, a dial indicator, a timing light, and the time.

031 Ignition Modification from Points to Chip

One thing that is sorta confusing is his statement that the original points flywheel position is already 30 degrees (or so) too far advance for a chip which suggests retarding it (adjusting it clockwise) would be required to correct it..., exactly the opposite of everything else I've read. Just another example of the confusing info out there, or am I completely missing something?
 
Having worked in a Stihl shop in the old days on lots of 031's I can tell you they had very hard to fix ignition problems,especially the points models. From factory the flywheel magnets were not in sync with the point opening for firing, and replacing all components did not cure them. the aftermarket little electronic modules worked sometimes,sometimes you had to reverse the wires as the part suggested. Try that. Otherwise...
 
I wasted endless hours of shop time trying to cure 031 misfiring ignitions .Today I would not waste my time,if you get lucky and one works,good for you!!
 
I think it's pretty common knowledge that the points setup on the 031AV had major issues, mostly attributed to the capacitor, which in turn created ongoing problems with points deterioration over time..., usually resulting in the saw simply being set aside as a lost cause by anyone who'd spent much time fighting with em.

On the other hand, the more adventurous folks started playing around with Atom and Nova modules with varying degrees of success (or failure) over the years resulting in the overwhelming amount of confusing information available out there today.

A modern MegaFire chip and an electronic ignition flywheel seems to be the ticket for easily giving a points 031 plenty of new life. Problem there is the flywheel availability, hence the alternative approach of advancing a points flywheel instead. Many seem to have done so successfully to one extent or another simply by dumb luck if nothing else.

The other problem becomes quite evident just by doing a search of "031 ignition" and reading all the different results related to converting from points to electronic ignition on an 031AV. Different chips, different polarity, different flywheel advance (or retard), no flywheel advance, different results all over the map depending an any combination of all those factors.

The latest consensus on the conversion seems to favor a simple points flywheel advance from somewhere between half a key width to 1 1/2 to 2 key widths in order to get the timing to cooperate. It also seems as though the effectiveness of each person's approach is in the subjective eye of their individual efforts and not necessarily in quantifiable or measurable results.

The 031 is a great saw when running right and there are a ton of em out there for cheap. Just a shame that someone hasn't taken the time to sort out the ignition conversion issue in detail once and for all. A dial indicator and timing light would pretty much do it if the person knew what they were doing. Measurements with repeatable results could be established and converted to using a degree wheel or simply setting up specific timing marks on the case and flywheel for a successful conversion every time with no guesswork at all. The link I provided got close but lacked the detail to make the whole process as simple as it could be. I don't have the means or the time (or the brains, actually) to put something like this together. Was just hoping someone out there already has and I've just not run across it yet after nearly a week of searching and coming up empty so far.

Locate chip and establish good ground to ignition if a single terminal chip is mounted in airbox as airbox is isolated from ignition ground by the a/v system. Wire chip into ignition system in place of points and condenser. Find TDC using a degree wheel or some other means. Rotate the flywheel whichever direction however many degrees have been already determined to achieve 25 degrees of timing advance at 8000rpm as described in the service manual. Tighten nut. Done. Seems simple enough.

I got the one I've been struggling with running pretty good today like most folks do.

Dumb luck.
 
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