Was aware of a wobble on the fan belt, figured it was a loose bolt or two. Had some time just now and started poking around, fan bolts seem tight, etc. Fired it up, it idles nice and smooth.....looked at things while in motion - AND THE !@#$% BALANCER AND PULLEY ARE DOING THE WOBBLING!

Where do I start looking, what do I have going on here? I took a video and saved to my computer but it's an MP4 which the forum won't accept. I'm not on YouTube, what's the best way to post it?

PM sent...... if you can send me the MP4, I can get it on Youtube to post.....

Engine? Horsepower?
Does it have a bolt in the end of the crank and is it tight?
Is the outer ring on the balancer moving around - rubber deteriorated?
Correct woodruff keys in the crank?
Sheave / pulley correctly indexed?

Believe I'm missing one of the bolts holding the balancer on, possibly overlooked that on assembly. Going to remove a second bolt to determine size and grade. Hoping it's as simple as loosening the alternator to remove belt tension, installing all bolts anbd re-torquing them all.

327/300 block originally, I have it derated to 250hp. Will advise more in a bit. Thjanks!

It wasent until 66 or 67 or maybe later that the base engines ballancer was only a press fit SHP cranks where drilled and tapped for a bolt

I think you are referring to the bolts that fasten the crankshaft pulley to the harmonic balancer. The harmonic balancer itself typically doesn't have a retaining bolt into the crankshaft on a 250 or 300 HP engine. The higher horsepower engines had a bolt into the crankshaft to retain the harmonic balancer. I would first remove the belts, make sure the pulley is bolted securely to the balancer and then see if you can feel any play (looseness) with the fit of the balancer to the crankshaft. There should be NONE. If there is, you'll need to remove the balancer to inspect the condition of it's bore and keyway, the condition of the crankshaft snout and the Woodruff key and keyway. Also, check that the outer ring on the harmonic balancer isn't separating from the inner hub. The vulcanized rubber that attaches the two components is well known to break down over time.

Ted

Pulley to balancer bolts are all at 60 ft/lbs. Wobble remains. Removed belt, ran it briefly and wobble remains. Dad's 66 427 will post a 4 second video for me when time permits.'
'
At this point I'm agreeing with the suggestions the balancer itself may be the culprit.

Here you go.......

Looks like it's delaminating. Pretty easy swap. I rather do this task on a C2 any day of the week compared to a C5.....that's a PITA!

I agree. Looks like the balancer is coming apart. Don't run the engine. Pull it apart. You may need a puller. They are cheap at Harbor Freight or you may be able to rent one for free at your local auto store like Advance Auto, Auto Zone etc. If you want to keep the original, send it out to Damper Dudes or the Damper Doctor in CA. Inspect the crank snout and measure it with a micrometer to see if it has degraded. There is a kit available to dress up the crank. Very lucky that it did not come apart and take out your hood, radiator or you, if you were near it with the hood open. Good luck. Jerry

That was my next question. I have a twice-postponed date for alignment and inspection, a week from tomorrow. I could resist the urge to go for a ride, but was going to ask about on and off the trailer a couple times and into the shop for the work. I'm hearing don't even think about it.

Remember what Dirty Harry said. Do you feel lucky? The damper companies usually turn them around in a few days. Jerry

Confirm whether or not there's a center bolt securing the damper to the crank. If so, confirm that it's tight. If no bolt, confirm whether or not the crank snout is drilled for one. If it is drilled, take care to not bugger the threads with a puller as you remove the damper.

Live well,

SJW

Yeah, with this project, "lucky" isn't even in my vocabulary any more! Not going to turn the key till this is resolved.

I'm not going for judging, ZIP has them for under $100. Can have it on its way tomorrow.

Crank is not drilled for center bolt. I cannot cause ANY wiggle of the balancer by using my hands to yank or wiggle.

Does not appear to be working its way off the crank. But, the paint on the rubber part of the balancer does not look disturbed, no flexing there?

Looking at the video, I agree it is the HB that is bad. Easy fix!

local auto parts stores will have them too

Thanks Keith, will check FLAPS. I'm taking stuff off now.

even though the one you need fits millions of SBC cars and trucks I highly doubt any parts store will have one in stock. But should be able to get you one the next day

Yeah, and I have had situations where the store's computer said a given part would not fit my vehicle, when I knew it did. Bought it anyway and it did fit.

Here's the front of the one that's there now. I don't see any signs of the rubber being distorted or coming apart. Same on other side. I suppose at this point I pull this one off and replace anyway?

Railroadman;
There is a tool; guide, drill and tap to drill and tap the crankshaft in situation. There is a YT video of this being done on a 63. You will need a puller to remove the balancer; install is difficult because you have to use blunt force to install, and swinging a hammer in the front of the engine with limited space is difficult. Heating the balancer is risky as the elastic bond can be compromised. Keep us informed as you proceed.
Aloha,
Rene'