Just because I've been seeing this discussed quite a bit .. how do you know when your Valves (lifters, etc) or Harmonic Balancer are in need of repair / replacement? What are the signs?

 

Beuler .. Beuler.

 

Balancer will fail by means of coming apart, leaving you near stranded or lucky enough to limp home. You will probably smell burnt rubber, have a CEL for boost deviance, lose power steering, have a battery light, any of these are a possible cue of its failure.

Don't concern yourself too much with valves and lifters, if they make noise fix it, if you're consuming oil chances are that you need valve guide seals done, at that point pull the head and have it gone through.

Lifters & valves aren't a common replacement item on these cars, but few have had worn lifters cause a clatter.

 

Failing valves and lifters will cause misfires. You'd diagnose that with a compression test. A failed HB will cause a X Mas tree of lights on your dash, loss of power, broken belt, and overheating if you keep driving it. You can diagnose it by removing the belt, if it's still there and trying to spin the outer half of the pulley. If it spins easily, break out the wallet.

 

Ok, I have none of these symptoms - but good to know so I know what to watch for.

 

At what point do the HB start failing? Is it by miles or years?

 

Random...it's good till it's not.
Some do 70,000 miles, some do 100,000+.... some many more...years....who knows...the rubber gets dry, and it cracks...heat, age, vibrations, who knows. Other designs are better, ATI, PRW, or more recent speed master seem to be favorites....this desgin that fails was used as a sheer clutch on many piston aircraft alternators pullies for years....failure mode is the same...resulted in many problems on "Beachcraft/Raytheon Barron airplanes as well as others....
But you can easily look at it when the passenger side tire is off, just yank out the wheel liner...if you do it when you change your belt (hopefully either yearly or bi-yearly depending on how much you drive) you can look it over....
Alternately, you can put a pry bar on it when on a lift, and see how much flex it has....

There are two styles....a pre-facelift version, and a facelift version...both fail...at some point...
Then again EVERYTHING on a car will someday....
So drive and enjoy!! If you drive in fear, you will never have fun.
With somethings you just have t run them "on condition" and replace them as they fail inspection....that's where looking EVERYTHING over, basically inspection 2, pays off...
Folks that just change the oil, and do the fluid are really lieing to themselves....the purpose of a preventative maintenance plan is to inspect stuff, and catch it early, before it gets you stuck.
Know the symptoms....and just know it MIGHT happen....but it might not...like everything else you read.