ekennedy21 Posted May 17, 2019 Share Posted May 17, 2019 Does anyone have any info on timing a 29 AC? Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/ Share on other sites More sharing options...
paulbrook Posted May 17, 2019 Share Posted May 17, 2019 1. Check that the magneto points are set to the right gap (15 thou for a FU4) 2. Set the mag at full advance 3. Set cylinder no 1 (front of truck) to 20 degrees or 3 inches on the flywheel before top dead centre (check through the upper airduct hand hole, there is a pointer) 4. Unclamp the mag drive so that the mag shaft can be moved independent of the engine and rotate so that the distributor arm is pointing at the sector in the cap that corresponds to the lead running to No1 cylinder 5. Fine adjust the mag so that the points are just opening (you can put a bulb and battery across or use a multimeter) then clamp up the mag drive. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-422987 Share on other sites More sharing options...
ekennedy21 Posted May 17, 2019 Author Share Posted May 17, 2019 2 questions if you could, Where is the upper air duct hand hole? and how do I unclamp the mag drive? Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-422993 Share on other sites More sharing options...
ekennedy21 Posted May 17, 2019 Author Share Posted May 17, 2019 also my magneto is a bosch zr4 with an impulse if that matters Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-422994 Share on other sites More sharing options...
41chevy Posted May 18, 2019 Share Posted May 18, 2019 The hand hole/ inspection cover in in the drivers compartment fan cover. Rectangular cover held on with 8 screws. Interested on how to unclamp the magneto too. Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423035 Share on other sites More sharing options...
ekennedy21 Posted May 18, 2019 Author Share Posted May 18, 2019 seems to be running well now, but it is idling substantially higher then before the magneto rebuild. Could his be related to the timing? Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423085 Share on other sites More sharing options...
41chevy Posted May 18, 2019 Share Posted May 18, 2019 Possible but also may be a matter of readjusting the low speed jet and idle screw to bring it down. The idle may have been raised to compensate for the wear issues in the magneto when it was a working unit.. Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423092 Share on other sites More sharing options...
ekennedy21 Posted May 18, 2019 Author Share Posted May 18, 2019 Is that the t screw on the bottom of the carb bowl that sticks out at an angle? Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423099 Share on other sites More sharing options...
ekennedy21 Posted May 18, 2019 Author Share Posted May 18, 2019 never mind. Found it. The screw up by the throttle plate. Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423106 Share on other sites More sharing options...
paulbrook Posted May 19, 2019 Share Posted May 19, 2019 On 5/18/2019 at 7:07 PM, ekennedy21 said: seems to be running well now, but it is idling substantially higher then before the magneto rebuild. Could his be related to the timing? It could be - if you are slightly to far advanced at idle it will run a bit quicker. More likely to be the carb though. As long as you don't get pinking when pulling with the ignition advanced then the spark must be more or less in the right place. Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423151 Share on other sites More sharing options...
ekennedy21 Posted May 20, 2019 Author Share Posted May 20, 2019 somebody told be that switching from a zenith updraft carb to a stromburg sf-2 will fix all my problems. Quote Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423170 Share on other sites More sharing options...
41chevy Posted May 20, 2019 Share Posted May 20, 2019 (edited) 2 hours ago, ekennedy21 said: somebody told be that switching from a zenith updraft carb to a stromburg sf-2 will fix all my problems. There a 9 different venturi sizes for the Strumberg SF2/SFM2 they range from 13/16" up to 1 1/16" and some have a Drip Tube set up to prevent gravity siphoning of fuel on shut down. I personally think checking the throttle linkage is allowing the butterfly to lay against the curb idle screw, adjusting the Zenith Lo Speed mixture and fine tuning it overall to work with the modern crap gas would be you best bet. My ACs all have different carbs, 3 have Tillotson, 2 have Zenith and 1 has a Strumberg SF1/SFM1 . Edited May 20, 2019 by 41chevy Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/57258-properly-timing-a-1929-ac/#findComment-423176 Share on other sites More sharing options...
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