[AJD] Unstyled B conundrum

[John Nordhoff]

  Mike, Sorry I cant give you the exact short answer youre looking for, but I may be able to help some:
 
  IFFFFF
 
  1) Theres no provision for adjustment of the lag angle on that mag (or any adjustment still dont bring it to spec)  and
 
  2) Regardless where the mag is rotationally adjusted in the governor flange (CW or CCW) she is NOT impulse tripping at LHI,,,,,,Its possible the governor gear to cam timing may be off.....
 
  Heres how one might check and/or adjust the cam to governor gear timing WITHOUT using any timing marks on either gear.
 
  Get the left piston up to TDC,,,,,,If the flywheel is on the correct crank spline (and crank and cam are in time) that would correspond to when the flywheels LHI mark is at the line on the tractor in the 3 o clock position,,,,,,,,AT THAT POSITION THE OPEN FEMALE SLOT IN THE END OF THE GOVENOR SHAFT (where mags coupler mates) SHOULD BE FLAT HORIZONTAL FORE N AFT......... If not the governor gear isnt in time with the cam gear which can be changed by raising the govenor (dont forget the oil line needs removed) and meshing its gear to the cam so the open female slot is flat horizontal fore n aft.  
 
  As far as any lag angle adjustment or drive cups on the FM Mag I KNOW NOTHINGGGGGGG 
 
 
  Let us know what happens
 
  John T Nordhoff in Indiana> From: buck69_hunter at hotmail.com> To: antique-johndeere at lists.antique-tractor.com> Date: Sun, 1 Feb 2009 17:20:15 -0600> Subject: [AJD] Unstyled B conundrum> > > I looking for an answer to a problem that started in 1945 or 1946.> > Sometime in 1945 or 1946 my 1935 John Deere B was fitted with a modified short-lug coupler Wico X magneto, I'll assume to replace its 'problematic' F-M DRV2B. As many of you are aware of, aside from the lug length, there is also a difference in the lag angle between short and long lug coupler. > > My Wico X has the 6274 short lug coupler, but the lugs have been lengthened nearly 3/8". I don't know what was done if anything other than the lug lengthening.> > In the 30+ years that I've had the tractor, it has always run well, but 2 years ago I decided to restore it so my grandson can drive it in parades and things like that.> > Since the tractor will be compared to others of similar vintage, I decided that I'd try to get as close to the way it was when it left Waterloo as my pocket book would allow. With that in mind, I bought a F-M DRV2B. It is a good mag the throws a nice spark when I bench test it. > > Here's my problem... When I put it on the tractor I cannot adjust it to where the impulse trips anywhere near "LH IMPULSE". It's still too cold here in Minnesota to work in an unheated garage and when it warms up I plan to pull the governor case to see if there are register marks on the cam and governor shaft that might show that I am off register. I've explained my problem to an expert and been told that there is a fair chance that I'm looking in the right direction.> > Here's my question... Is there anyone out there that has encountered a similar situation that can say "Yes, this was a common practice" or "No, a single gear tooth off would give you more than the difference in lag angle between the long and short lugs".> > Any insight is appreciated!> > Thanks in advance,> Mike> _______________________________________________> Antique-johndeere mailing list> http://www.antique-tractor.com/mailman/listinfo/antique-johndeere