Timing on a A

I'm thinking the cam gear is not so easy to fix but something similar to the above fix may be possible at that. Cam to crank gear misalignment will effect valve opening timings, but governor to cam gear won't.

Rotate the flywheel so the left hand (flywheel side) piston is at TDC on its compression power stroke. At that position, the flywheels Left Hand Impulse timing mark should be in the 3 o clock position in line with a mark on the side of the tractor. NOW ALSO AT THAT POSITION THE FEMALE DRIVE SLOT IN THE GOVERNOR SHAFTS END (that drives the mag) SHOULD BE FLAT HORIZONTAL FORE AND AFT. If its not, it could be a tooth off to answer your question.

Now as you already indicate knowing, the mags START TIMING should be set to fire right when the flywheel passes that 3 o clock mark. Rotate it CCW to advance or CW to retard. If it wont rotate enough to do that, you could be a tooth off on the governor shaft (see test above) or the mags not right.

As the Clooney man pointed out, the lag angle settign is what determines the different timign between START and RUN advance on the Wico's or many other mags.

You might first wanna check that governor shaft location at TDC and 3 o clock (flat horizontal) then post back your findings and get into the lag angle/ run advance settings.

God Bless the USA John T Nordhoff in Indiana

Thank you for the info again. I thought my timing make on the fly wheel was off. After looking at this again along with some other checks it is correct. The implulse happens now at about 4 deg. before TDC. My running timing is about 35ish BTDC. So at this rate I am just about rite where it should be for best perfomance. I can back if off a little if need be. More than likely the govenor gear is off a tooth, but that will waite for another time. You made the comment that I need to pull the end cap off slowly or the ball bearing will fall out. If I do this slowly what is the chance that they will still fall out? John T. I have this bored out .125, head milled .250 (to the eye brow) with some porting of the head and intake runner. I did have 46 hp at 540 pto RPM and it will pull down to run at about 51 hp. I only run 94 octane gas in it. I am not after the BIG hp. I just want it to run to its best. I take pride in that type of thing. I know you guys understand where I am coming from.

THANKS AGAIN BUDD

First, if you're at near stock compression (which is low on that tractor) and you're not runing at any super fast RPM or using any exotic fuels or have a performance cam, simply further and further advancing the timing is no cure all or winner. It's when youre at high compressions requiring higher octane fuels (which are harder to ignite) and at high RPM and maybe had some cam work done, when you need more spark advance. If you have access to a dyno, what I suggest is hook on and then adjust the run timing to achieve max HP. I suspect that somewhere between maybe 22 to 30 BTDC is where shes gonna peek out at assuming you have near stock compresion and fuel and cam etc.

As far as mags, if the pullers run at high compression and therefore have to run higher octane fuel, they need a higher energy spark, and they buy the hot performance mags which have schedule 8 high magnetic strength rotors and hot coils. Again, its not so much incresed advance they are lookign for, its more spark energy necesary to jump a gap at those higher compressions.

The usual ways to improve pulling pefrormace are upping the compresion with domed pistons, milling heads, or adding cubes via borign or stroking and THEN getting more spark energy. You also need to rid the tractor of horsepower robbers to whatever possible extent such as any hydraulics, generators, fans, water pumps, heavier than needed lubricants, air inlet and exhaust restrictions etc etc.

Good fun topic you started. John T

For your question, how far can you advance to and still start, they can be much farther than recommended and still start HOWEVER its tough on starter drives if they try and kick back (which is what happens if she fires too soon BTDC at start) and tough on hand crankers as they also want to kick the flywheel backwards. Depending on the tractor and mag, she might start at 5 to 10 BTDC, but is again, hard on starter drives (if too fast) and hard to start and wants to kick the flywheel back cuz she fires before the piston is up to the crossover point. I set my mag start timing to be at TDC or maybe just slightly before, depending on how she performs, but NOT 5 after as yours now is. I tend to set my hand crankers slower than electic starters, cuz I hate if they kick back and burn my fingers.

That takes us back to your original issue, why you cant rotate the mag CCW enough to get the start timing to TDC in lieu of ATDC, so see where the governor slot is at TDC per my above, and if it checks out, then take a closer look at the mag.

You're gettign there, Good Luck n God Bless

John T Nordhoff in Indiana