Why you should replace old harmonic balancers - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevy_mike · 06-08-2017, 11:17 AM

When I first bought my C10 panel, I knew the outer ring on the balancer had moved, as I could never get the timing marks to line up. It has been a long term project so I finally got around to pulling the old balancer to replace it. Wow was I surprised how bad it was!!!

Folks, this is why you should never trust an old balancer. The rubber breaks down and then starts to fail. This is the worse one I have ever changed.

Ring not only spun but was walking out. The pulley kept it on.

From the backside, you can see the missing rubber and it pushing out. Glad I never drove this!

BossHogg69 · 06-08-2017, 11:30 AM

Good thing you caught that... It would've been an expensive mess under the hood coming apart at speed.

Lugnutz65 · 06-08-2017, 09:32 PM

I recently bought a 1963 truck. When I spun the fan and fan belt by hand, the engine did not feel like it had good compression. I was told that the engine would run but I was not very convinced.
I cleaned things up under the hood and noticed that the harmonic balancer was spinning in place when I turned the fan belt by hand. I had another harmonic balancer handy and replaced it. Engine runs pretty good.

06-08-2017, 11:17 AM	#1
chevy_mike Never Ending Projects Join Date: Jul 2006 Location: San Diego, CA Posts: 3,836	Why you should replace old harmonic balancers When I first bought my C10 panel, I knew the outer ring on the balancer had moved, as I could never get the timing marks to line up. It has been a long term project so I finally got around to pulling the old balancer to replace it. Wow was I surprised how bad it was!!! Folks, this is why you should never trust an old balancer. The rubber breaks down and then starts to fail. This is the worse one I have ever changed. Ring not only spun but was walking out. The pulley kept it on. From the backside, you can see the missing rubber and it pushing out. Glad I never drove this! __________________ . 1965 C10 Panel, Tiki Express http://www.67-72chevytrucks.com/vboa...d.php?t=506580 SOLD 1968 Chevy C10, Long, Fleetside, Hot Rod Hauler http://67-72chevytrucks.com/vboard/s...d.php?t=313233 SOLD 1965 Chevy C10, Long, Fleetside, Hot Rod C10 http://67-72chevytrucks.com/vboard/s...d.php?t=415702 SOLD We were given two ears and one mouth for a reason... listen twice as much and speak half as often...

06-08-2017, 11:30 AM	#2
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: Why you should replace old harmonic balancers Good thing you caught that... It would've been an expensive mess under the hood coming apart at speed. __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!

06-08-2017, 09:32 PM	#3
Lugnutz65 Registered User Join Date: Jan 2013 Location: Columbia, SC Posts: 1,926	Re: Why you should replace old harmonic balancers I recently bought a 1963 truck. When I spun the fan and fan belt by hand, the engine did not feel like it had good compression. I was told that the engine would run but I was not very convinced. I cleaned things up under the hood and noticed that the harmonic balancer was spinning in place when I turned the fan belt by hand. I had another harmonic balancer handy and replaced it. Engine runs pretty good. __________________ My 65 C10 build: www.lugnutz65chevystepside.weebly.com Want to know more about T5 transmissions? My website has a T5 Info Page and a Step by Step T5 rebuild.



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