[Havoc65]

So Friday I was driving down the road and heard a loud bang followed by the sound of something hitting the floorboard as I drove over it. I shut the car off and pulled over to find a coolant leak from my lower radiator hose. I was able to repair it and get the car home and then replace the hose. I assumed I had run something over and it hit the hose as it passed under the car. Everything seemed OK so I’ve driven it the last couple days. I was under there doing some work this morning and found a large chunk of the outer portion of the harmonic balancer laying on the frame rail. The other half is what I must have heard banging on the floorboards. The car driving and running fine and there are no weird vibrations. Obviously I need a new damper but did I damage the engine potentially by driving it like this? Should I not run the engine again until I’m able to get this repaired or to be OK drive it around my yard. What do you guys think?

 

[Nailbender]

I'd say buy a lottery ticket! You probably didn't hurt anything. I wonder what the country of origin was on that aftermarket balancer?

 

[Havoc65]

No idea it came on the car but it looks ancient. I just finished installing front end parts and need an alignment. I was thinking I’d get it towed over since I have free towing. Think it’d be safe to drive it home? Probably be a week before I have time to replace the balancer.

 

[Nailbender]

Free towing! The next piece to fly off might do some damage. I didn't realize you or somebody had put timing tape and fresh paint on the balancer.

 

[Havoc65]

No paint but I put some timing tape on there years ago. The original timing marks were very hard to read. I think it’s probably the original balancer but not positive.

 

[Klutch]

Since a factory, small block Ford is externally ballanced, I would expect it to shake like crazy without the balancer. But I admit I've never run a small block Ford without the balancer. Is it possible your engine was internally balanced at some point? This would require an aftermarket harmonic dampener which really wouldn't be a balancer.

 

[Havoc65]

Since a factory, small block Ford is externally ballanced, I would expect it to shake like crazy without the balancer. But I admit I've never run a small block Ford without the balancer. Is it possible your engine was internally balanced at some point? This would require an aftermarket harmonic dampener which really wouldn't be a balancer.

weird isn’t it? I literally drove it 2 days like that and was oblivious, no unusual shaking or anything.

 

[Shaun]

I had a stock one explode off a 289 doing 120mph into turn 5 at Road America. That was exciting! Apart from a few dents in the oil pan and a lot of clanging and banging under the car no damage. Drove it just fine back to the pits... Slapped on one from a junk yard later that day and ran the snot out of the car the next day!

 

[DustyB]

The balance weight is in the balancer hub and thats still attached. The outer ring may have a few holes drilled in it to fine tune the balance. Being a small diameter, any of the drilled holes have an almost insignificant effect. Factory engines weren't finely balanced anyway and replacement balancers aren't balanced to your engine either. Biggest issue might be the function of the rubber layer. I'd say, very little harm possible, but do replace it.

 

[GT289]

I'd be concerned about running that engine without a harmonic balancer...... even for two days.
About 99% of the 289 crankshafts we checked (magnafluxed) at JBA had cracks in them.

Really surprised you can't feel anything with the engine running.

 

[Killer95Stang]

Replace it with a new SFI balancer and call it day....