jay in nc 209 #1 Posted June 2, 2012 have been working on my 68 commando 8, getting it ready to take to pa. i have noticed the s-g gets very hot after eaven after 5 min. of run time. i took it off and spun it by hand & it's very smooth & quiet. it starts well, and the headlights, taillights & cigarete lighter all work. do i have to polarize it because it has been seting up sence 2005 when it threw the rod? the regulator looks new inside, with no pitting or corosion on the contacts. the battery is new. thanks Jay Share this post Link to post Share on other sites
bowtiebutler956 649 #2 Posted June 2, 2012 I think its normal Jay. Mine is the same way. Matt :flags-texas: Share this post Link to post Share on other sites
condo630 6 #3 Posted June 3, 2012 I never noticed mine getting that hot when it was working right. It sounds like the rest of your system checks out, but I do know that excessive heat can kill a S/G dead, so you might want to take a good look at it. Share this post Link to post Share on other sites
ol550 830 #4 Posted June 3, 2012 Would recomend checking the output voltage when running full throttle. No more than 14.2 volts. You might have a bad voltage regulator. Mike Share this post Link to post Share on other sites
Save Old Iron 1,564 #5 Posted June 4, 2012 Jay, heat will either come from mechanical friction (bearings, bushings, armature / field shoe contact) or from electrical components like field coils or excessive sparking at the commutator and brushes. If you have a spot reading infrared thermometer, point the device at the front and rear bearing areas a few minutes after a cold start. One of the bearings / bushings being SIGNIFICANTLY hotter than the other may signify a failing bearing. Measuring the area in the center of the SG motor would indicate if the heat source was from the armature rubbing on the field shoes (after the unit warms up and parts expand). This might indicate one of the bearings supporting the armature is allowing the armature to shift slightly and start rubbing on the field shoes (metal against metal). You can check for electrical issues involving the field coil by removing the field wire from the "F" terminal on the SG motor. This will remove all field current from the motor and stop any charge current from being generated. If the SG motor temperature is SIGNIFICANTLY lowered, you may have a partially shorted field coil or excessive sparking at the commutator / brush area. Visual inspection is best to isolate brush / commutator sparking issues. If you do disassemble the SG motor for visual inspection, confirm the area between the copper commutator bars is undercut beneath the surface of the commutators. If the copper commutators are worn to the point where the mica insulators are even with (or slightly above) the commutator surfaces, brushes will bounce off the mica insulators between the commutators and leave contact with the commutator surface. Excessive sparking results. Sparking = heat and excessive brush wear. Share this post Link to post Share on other sites
jay in nc 209 #6 Posted June 17, 2012 i put a brand new A C Delco regulator on it & it still gets super hot. so i took the field wire off and it stays cool. it has a new battery & starts instantly so i'll work on it after the show. the ign switch was changed sometime in the past. isn't it supposes to have a cut out curcut ? Share this post Link to post Share on other sites
clyde 5 #7 Posted June 19, 2012 is your s g putting current into your batt?sometimes if your regulator isnt working the current in you s g has nowhere to go.thus heat!trust me even new reg. are no good Share this post Link to post Share on other sites
