Crank Drive Gears

 

    The cam and distributor are both driven by gears located on the crankshaft.  The cam gear is a steel gear.  The distributor drive gear is a fragile gear made of brass.  Much care should be taken when removing or installing these gears, especially the brass distributor gear.

1 -  crank-camgear-teeth.jpg (26823 bytes),      2 - crankgear-timingmarks.jpg (38849 bytes),      3 - gear-timingmarks.jpg (27745 bytes),      4 - dist-drive-gear.jpg (16929 bytes),

   Photo 1 shows a good used cam gear.  There is some slight surface rust on a few of the teeth, but it looks good.  If you can, it's a good idea to have the cam drive gear magna-fluxed to check it for cracks prior to installing it on your crank.  Photos 2 & 3 show the timing marks on the cam drive gears. photo 4 is of the distributor drive gear.  Inspect this for bent teeth and other damage.  Minor damage can be filed with a good set of jeweler's files.

    The best way to remove and install these gears is by using a small propane torch to pre heat them up.  I've found that if I heat them up, I don't even need to use anything else to get them on or off the crank.

    Below are some photos of the proper sequence that your crank gears should be installed.  Remember that 2 of the main bearings are part of the gear stack.  Be sure you get Main bearing #3 on and with the dowel pin hole in the right position prior to installing the gears.  Once that is done, heat and install the cam drive gear.  Ensure the two timing marks are OUT when installed. 

timing-mark.jpg (35994 bytes) 

    Next, slide on the spacer and then heat and install the brass distributor drive gear.  If possible, make a driver out of pipe, that fits around the inside on the gear to tap on so that the light tapping force is evenly distributed throughout the entire gear.  If you must use a punch to tap this gear down into place, use extreme care not to damage the gears' teeth in the process.  

crank-spacer.jpg (44549 bytes)             crank-dist-drive-gear.jpg (41938 bytes) 

    After you install the snap ring into the groove, install the #4 main bearing as pictured and then slide on the oil slinger.  Ensure the outer edges of the slinger are closer to the end of the crankshaft (concave side toward the end of the crankshaft).  If the slinger is installed backwards, oil could be blown out during use from around the crank pulley. 

crankbearing4.jpg (32126 bytes)             oil-slinger.jpg (30123 bytes) 

 


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