By Steve Goodman, Pikes Peak Corvair Club
The harmonic balancer is also known as the crankshaft pulley. In 1964 when the crankshaft stroke was increased the engineers added the harmonic balancer instead of the simple pulley on the 1960-1963 engines. The concern was the longer stroke could set up some vibrations(harmonics) in the crankshaft at certain rpm and cause cracking/breaking of the crankshaft.
The balancer is two pieces, the inside which is the hub to bolt to the end of the crank and an outer ring with a rubber type sleeve between the two metal parts. There was a vulcanizing/gluing adhesive applied to keep the two parts together.
Unfortunately, after heat works at making the rubber hard and oil spillage and leaking tries to soften the rubber, there comes a time when the outer ring becomes loose. Since the timing mark is on the outer ring many times the looseness of the part will show while setting the timing due to being in a different position. While running the outer ring always is pulled away from the engine (towards the rear of the car) and what is in the way of the pulley as it comes backing out??? The oil filter!!!
The oil filter ‘can’ is very thin metal and within only a few minutes of having the ring rubbing against the side of the filter the result will be a very quick mess and oil will cover the engine; especially if the engine is at speed on the road.**
There is NO quick roadside repair for this, the balancer must be replaced. Note how the pulley is against the oil filter in the above picture.
Look at the oil filter above and notice the paint worn off and metal showing. Also, there is a ‘hash mark’ across both pieces of the balancer and the old part shows the movement between the two pieces. The old pulley still on the engine.
In the photo above, notice the outer ring is pulled away and the hash marks not lined up.
The picture above of the fresh balancer shows where I used a white Sharpy to highlight the hash mark and also the timing notch on the outer edge of the pulley.
Balancer failure is not the most common occurrence but occasionally look the engine over while idling and just watch things in motion as well as listen the nice smooth ‘whirring’ of the engine.
**Unless your engine has A/C or smog, then the 90-degree filter adapter keeps the filter out of the path of the spinning ring.**
In these cases, the ring finally falls off the hub, the fan belt is flipped, the gen/fan light shines brightly and the driver sez “darn my belt has come off”. When the mess is discovered, a tow is necessary.
*********************SFBA NOTE**********************
If you’re so inclined, changing out a harmonic balancer (or a solid crank pulley) is not too difficult or time consuming with the proper tools.
As Steve mentioned in the article, once the battery is disconnected, the first thing you want to do is remove the fan belt. Then, the oil filter. At this point you can replace the bad balancer and the seal. Blue Chip Tools sells the perfect tool for this job.
If you don’t want to make the purchase of this specialty tool, send up the bat signal to SFBA. A few members have this tool in their toolboxes.
You can find the correct harmonic balancer replacement and seal here
Have any tips or stories about harmonic balancer failures? Share them in the comments.
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