The Stovebolt Site Forums The Shop Area Engine Shop harmonic balancer won't stay tight

I have the 54 car 235 running well. drive shaft and exhaust are installed.
the muffler guy noticed the balancer wobbling and sure enough it was not tight.
when I assembled the engine I used the repair sleeve on the crank and drove the hb onto the crank. it sounded and felt like the balancer was seated.

I was ready to put the front end on but now it's on hold until I get the hb fixed.

what are my options at this point?

it's a 54 car 235 in a 53 3/4 ton

thanks
rolf

You can drill and tap the end of the crankshaft and then use a bolt and washer to hold the balancer on. Is the inside of the balancer hub worn? keyway worn? I would be concerned about both of these. The balancer should fit tight to the crankshaft.

I have a 1960 261 that had the front of the crank knurled - I luckily found out last year that this had been done because the balancer hole was a little wallowed out.

We put on a different balancer - it was good and tight.

We had already drilled the snout of the crankshaft (using Hotrod Lincoln's loaner drilling jig - thank again, Jerry) - this is a nice "insurance-policy".

I agree with Don, the balancer should fit tight on the crank no matter how you hold it there. Drilling the crank is pretty easy, the material is not hard, but you do have to go straight and a couple inches deep. 100% centered is not totally needed, I did my with a hand drill. Pull the balancer off and measure crank and inner hub diameter and see what you get. Someone will come along to give you the correct measurements to compare to.

Joe

The crankshaft snout should measure 1.125", and the balancer hub should have an ID about .002" or so smaller than the crank snout. If the keyway isn't worn where the balancer can rotate back and forth, just drill and tap the crankshaft snout for the same 7/16-20 center bolt and washer that's used on the 1970-up small block V8 engine. A worn key slot in the balancer requires a new balancer, or another key slot can be broached in the old one. A worn Woodruff key slot in the crankshaft can be welded and re-cut by a good machine shop, but it's an expensive fix that requires a full teardown of the engine.
Jerry

i have to work the next 7 days and i won't get to the truck.

i did send the hb to dales out in salem, or.

i do remember that before i put the sleeve on the crank the hb would go on tight but you could pull oneside then the other and wiggle it off.

when i get off work i'll make the measurements mentioned above.

it appears that my only option at this point is to drill, tap, then bolt the hb on.

thanks everyone i'll get back to you on the hb and crank stuff when i get off hitch

rolf

It sounds like the crank snout is damaged. A repair sleeve is normally installed onto a harmonic balancer, but not the crankshaft snout.

Remove the harmonic balancer. Feel and look at the crank snout. If it is worn at all or the key is loose at all you need another crank shaft. Or at a minimum you need the snout welded and the keyway repaired.
This is a very difficult repair that can warp the snout alignment with the centerline of the main bearing journals.

I would recommend tig welding the snout to buildup the diameter, fixing the keyway, and having a crankshaft machinist regrind the snout to the original diameter.

Better yet. Find another crankshaft. It will keep loosening up. Remember, there were many years Chevrolet didn't even use harmonic balancer snout bolts.

And I agree with the previous post, replace the harmonic balancer with another one. No wear is permissible. Remember it's a non-moving part. It shouldn't be worn and if it is that is because it has a problem.