250 chevy harmonic balancer.help

So i finally decided to do my rear main seal on my 65 chevy pickup.I followed the instructions [chilton manual] and loosened all but the front main ,installed the seals,buttoned it up and now the balancer is not going flush with the crank snout as it was before.the timing cover seal is all the way in and the balancer is bottoming out on something solid and seems home ,but that half inch has me stumped. Im really hoping its something simple as im disabled and it took me almost a week to do this job .did i mess up something here.Could the crank have moved backward on me? Any insight would be welcome thanks ron

 

Probably your key has slipped and is not in the groove correctly, pull the balancer back off and locktite the key in and oil the crankshaft good when installing the warm or heated up balancer.

 

Thank for the quick responses,I put the balancer on without the key in it and got the same results so it looks like the pan has to come off again.I would of never thought the crank could move back with everything [flywheel ,clutch,trans etc] still attached.looks like a few more days till i check back with results.the only good thing here is that the second time wont be as much a bear as i now know the steps to get the pan off and the bolts for the motor mounts are now new.Just sucks as i have 30 inches of stainless rod in my back and the screws to attach it which makes it tough.Always thought i was a tough bastard til i got crushed, Thanks again and ill be back for an update ron
Just one more question .if i pry the crank forward and then back ,wouldnt that put me in the same position im at now?

 

Do the obvious (check for burrs).

Is your balancer the solid type (without elastomer)? If so try putting it in the oven, say 250°F for an hour, put a bit of motor oil on the crank snout. The balancer should slip on all the way.

Worked a long time ago when I did it on a buddy's 283.

 

Are you sure the pully was flush with the crank before? Measure where the damper bottoms out on the crank and be sure before you pull the pan.

 

For some reason ,perhaps wear the balancer is loose on the crank so i know its in as far as it will go.and its a rubber band style balancer.I would like nothing better than to drop a sm blk in there but its not in the cards this year.heres a pic of the truck as we all like pics.sat under a tarp for eight years ,just want to make it reliable so i can tackle bodywork.i call it a leaky tarp find lol

 

Also confirmed the balancer was farther in as now its abouth 1/2 of an inch away from the fan blades,before it was abou an inch or so.

 

There is NO way the crank could have shifted that much ! Think about it ,you were able to tighten tha main caps back up and the rear seated well enough so the pan fits OK right?? I have never seen a chevy damper/pulley that the front of it was flush with the end of the crank ,and that is 50+ years of screwing with them. The belt line up OK? If so you have NO problem!
Edit just read your last post, your issue sounds to me like the key in the damper has shifted assuming you did have the damper off. But again the end of the crank will be below the front face of the damper. There is no way in hell you could have gotten the main caps and pan on if the crank had moved that much,it is impossiable for that to happen.

 

Like he said. There is no way the crank shifted and lining to the belt is the best way to determine if the dampener is where it's supposed to be.

 

thats what i thought also ,but it is . also the alternater pulley is about the same distance off .T he pan went on ,no problem.The book [chiltons] says to loosen all but the front main cap as i did.I had the motor propped up on 2x4s at the mounts so it [motor] was tilted back at an angle but cant see how the crank shifted back.

 

Your crank did not shift back. Like others have suggested, remove the balancer and measure the distance from the front of the crank snout to the shoulder on the crank that the balancer seats against. Then measure from the back side of the balancer into the balancer bore to see exactly how far the crank protrudes into the balancer. You do likely have a burr on the crank or inside the balancer or the key is shifting and keeping the balancer from moving freely. No need to pull the pan, there is nothing in the pan that needs fixing.

 

I just went through that. My balancer was worn out and slipping. Since the crank is not tapped, getting it on took MUCH force and cuss words. If I were thinking, I would have the crank tapped when I rebuilt it.

I got it lined up the best I could and then got a hard 2x4 and placed it flush with the balancer. I then got a 2 or 3' 2x4 placed against the block so I could hit it from outside the bumper area. I used the biggest sledge I could wack with one hand and beat the snot out of it until it went on.

I also put the balancer in the oven for 45min or so, to help it expand.

It was a real bearcat to get on.

 

i had a balancer that was pretty much frush with the crank smout on a mid 70's 250. if you hammer it on i would remove the pan and put a block in between the crank balance lobe and the inner webbing to reduce mashing the thrust bearing. i know some folks who won't hammer them on at all but i haven't had any problems. i did brak off a puller bolt in the snout once, and i know that was bad! if it wasn't started perfectly square it might have developed a burr. i would def take it off and measure. that will tell you what the problem is. like everyone said the crank didn't shift that much. it's only supposed to have several thousandths movement. good luck!