Timing problem solved

[Kurt Combs]

I didn't post the problem I was having with my 72 F250 with a 360 and a C-6, so this is new. I thought I would share my experience here for others to see. Last Tuesday my truck would not start. It is usually very reliable. After changing the wornout points it would run, but not right. So I started checking the timing and finally decided to check the timing chain and sprockets because the distributor, number one cylinder, firing order, etc, all looked correct. After working on the truck for a while it would not run at all. Fire out the carb, but the timing looked good. Anyway, when I was disassembling the front of engine I found the problem. As I took the bolt off the vibration damper the key fellout in my hand. I looked in the groove of the damper and it was full of dirt, so the key had been out of its groove for over a year letting the damper slip on the crankshaft. I check the cam timing and all was well, so I reassemble and It runs. I rerouted the vacuum advance to manifold vacuum and it seems to like that. My hope is that it will start better when cold and not crank so long when hot, that remains to be seen.

So the point of my story is, sometimes it is the small parts that cause all the problems and they are really hard to find when they don't work right. Who would have thought about a little key causing all this trouble?

[ScottRod]

That sounds like the exact timing issue I'm having now with my 1984. How does the damper slipping cause it not to run right, or at all?
Am I missing something?

ScottRod

[knightfire83]

ScottRod,

If the damper is moving around on the crank because the key had sheared off, then the timing marks would be way off when you go to time it with a timing light.

That would be how it effects performance.

[ScottRod]

True, but only if you were setting your ignition timing to the marks on the balancer. I only go by the balancer if I'm checking timing on a running engine, but rather find TDC of the piston itself.
In my case, my balancer markings were right on at TDC, but my cylinders all check a very low, 55-60 lbs. compression, so I'm going to assume it's not my balancer markings, but my timing chain being off enough to allow some air to escape. At least I know why it's not firing. I must have reset my dizz about 5 times before checking the compression! I'm stubborn that way I guess...
Hope to get it tore down and back together by the weekend.

Thanks,
ScottRod