Factory timing chain 180* off?
Thread Starter
Instructor
Joined: Apr 2008
Posts: 109
Likes: 2
From: Hillsville VA
Factory timing chain 180* off?
I finally pulled my old timing chain today and found the factory chain was 180* off. My timing mark on the balancer has never lined up when I've tried to check timing, its always on the opposite side. I know the balancer slipped because it walked back towards the cover.
After rotating the crank and getting the #1 piston TDC, I pulled the cover and noticed a couple nylon teeth broke. Looking a little closer I noticed the mark on the cam gear was down and the mark on the crank gear was also down. I even rotated the crank again to make sure. Did GM do this on purpose?
Actually after all this, it still appeared to have slipped a tooth.
Kevin
After rotating the crank and getting the #1 piston TDC, I pulled the cover and noticed a couple nylon teeth broke. Looking a little closer I noticed the mark on the cam gear was down and the mark on the crank gear was also down. I even rotated the crank again to make sure. Did GM do this on purpose?
Actually after all this, it still appeared to have slipped a tooth.
Kevin
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I can't understand how it ran...but those plastic gears, I have a NEW one on the garage wall for grins,.....are total junk....
the crank dot on the timing gear should be at 12 oclock and the keyway as I recall is at 2 oclock....then the CAM gear can be in line on top OR on bottom, just depends wether cyl 1 or 6 is in compression for TDC both are actually TDC at that time, but only one at a time is in compression/firing order....both valves closed...
amazing how them suckers can skip teeth and still run....I actually got a old van home that a ways once...loosened the dizzy upon knowing what happened and played with enough timing to chug it home...saved my *** about 150 bux....
the crank dot on the timing gear should be at 12 oclock and the keyway as I recall is at 2 oclock....then the CAM gear can be in line on top OR on bottom, just depends wether cyl 1 or 6 is in compression for TDC both are actually TDC at that time, but only one at a time is in compression/firing order....both valves closed...
amazing how them suckers can skip teeth and still run....I actually got a old van home that a ways once...loosened the dizzy upon knowing what happened and played with enough timing to chug it home...saved my *** about 150 bux....
Thread Starter
Instructor
Joined: Apr 2008
Posts: 109
Likes: 2
From: Hillsville VA
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Rotate the crank one more time (1 at TDC ) and the crank timing mark will be up (12 o'clock) and the cam timing gear wiil be down ( 6 p'clock ). Cam timing gear is twice as big as crank, rotates at half the speed and this is reason you can't be 180 deg off 
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