I was wondering how to tell when a harmonic balancer is going bad? There is an odd metalic clanging that i can not isolate. It's been happening the last month. It seems almost sporadic, but i can feel and hear it more at 1100rpm in 2nd gear. Though it may appear at other speeds and gears. I've visually inspected everything under the front end and near the trans and engine mounts. I grabbed and tried shaking every moving part under the cab and front suspension but could not find any loose ball joints, nuts/bolts, etc...... I even opened the trans flex plate inspection hole and could not feel any give or free play in the plate to torque converter. I'm perplexed. The truck tracks straight and brakes fine.

 

The harmonic balancer inner and outer are separated by a rubber layer.

Best to see what the condition is just look for dry cracks in the rubber or install a stop in #1 spark plug and verify the balancer still shows true TDC

Josh

 

The harmonic balancer is made up from three parts: Outer pulley, inner damper and a rubber gasket.

At the factory, the gasket is placed between the pulley and damper, then the pulley/gasket/damper is pressed together forming a one piece assembly.

When the gasket age cracks, shrinks, this causes the outer pulley to "walk away" from the inner damper.

If not caught in time, the parts will separate, the pulley may strike the radiator core, taking associated parts along with it. Not pleasant.

 

I've had one explode on a Olds Cutlass just sitting in a drive through. I'm lucky it was front wheel drive and it just hit the inner fender. Made a nice little dent. Could've been bad if there had been a radiator in front of it. I found out later that there was a recall on those balancers...

Moral of the story, don't wait until it "seperates" to replace.

 

Here's a pic of my balancer. I am not sure how long that rubber has been peaking out, but that is bad, right?

I'm thinking of ordering a replacement from Summit, but have no clue what to get. I put my engine details(stock 351modified) in their search and i see four options:


PIO-DA-3512-HD

ATI-918930

PIO-DA3512

FLU-620200

Three are rubber dampers, one is liquid. The ATI one says it needs seperate hub. What is that? What do ya'll recommend?

 

ACH! Time to replace, the outer pulley is "walking away" from the inner damper.

Only a fraction of the very edge of the gasket can be seen when the balancer is OK.

Dunno what balancer you need since you haven't mentioned what size the engine is.

 

doh. i forgot to add the engine info. it's in the post above now. 351m stock.

 

Another question, do i need to install a new bolt or reuse the old bolt for the new harmonic balancer?