Re: IML: crankshaft pulley repair

[David Whitney <hazegreen66@xxxxxxxxx>]

The harmonic balancer is not engine specific IF IF IF IF IF your engine is internally balanced.  This is an important concept.  The '63 big block is internally balanced, as the cast crank was not introduced in the RB engine until nearly a decade later.  The 413 passenger vehicle engine was never produced with a cast crank.  '70s RVs and trucks, maybe.

 

The rule of thumb is forged crank engines are internally balanced, cast crank engines are external.  If you have one of the exceptions in your Imperial, you are already savvy and don't need to be reading this.

 

Externally balanced engines are identifiable by the presence of small blobs of metal near the outside circumference of the balancer.  That's how they are "balanced", and there is a relationship between that specific balancer and that specific engine.

 

Balancers do go bad when the rubber starts to deteriorate.  The early symptoms look like your timing is going bad -- pinging, rough idle, loss of power, technicolor smoke, frogs falling from the sky, etc.

 

A parts book and an interchange manual will steer you toward the proper P/N for your application.  There is no reason to refurbish a balancer unless you have a diagnosable psychiatric disorder that is commonly known by its initials.  Buy new and be happy.

 

To avoid worrying about your rubber, you can upgrade to a fluid damper.  More expensive, more durable.

 

When you change the balancer, you MUST be certain that the TDC mark (the one you use to set timing) is actually pointing to 0 on the plate affixed to the timing chain cover when cylinder 1 is at EXACT top dead center on the COMPRESSION cycle.  The most common mistake is getting it 180 degrees out.  Having it off by a few degrees will merely make it difficult to set the timing because you won't want to believe your eyes when you see how many degrees initial advance you have.

 

Some of what I have written is merely interesting.  The important sentences have words in CAPS.  Not abbreviations... words.

 

Happy motoring,

David

'91 K-Imperial driver
'66 LeBaron dual air and every option known to man

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