Project Geronimo: Getting Out Of The Balancer Groove

Recently, we managed to source a vintage, period correct, 283 cubic-inch small-block Chevy V8 engine for our first year C-series pickup. The original six-cylinder engine was tortured to the point of failure when the over-zealous driver pushed the aging iron past it’s limits. Fortunately for us, we travel in some unique circles and was able to locate the perfect replacement mill on a budget.

Facebook is a wonderful thing and minutes after posting a request for a 283 V8, we were private messaged from a friend. This friend is a dirt track racer that had purchased a car that came with the tiny V8. For most people, these 283 cubic-inch Chevys are nothing more than boat anchors, and our friend intended to scrap this engine when he saw our plea. We negotiated a selling price of 18 cold Bud lights for the transaction. Sold!

Experience

Our experience tells us that these Chevy V8s can be visually inspected to determine how much needs to be replaced or reworked. The timing gear cover was leaking, and our years of maintenance told us that we would need to replace not only the seal, but the timing chain, gears, and probably repair or replace the harmonic balancer.

Grooves in the harmonic balancer can cause leaks that are difficult to track down. Solving the problem once you find the leak is fairly easy and inexpensive though.

Explaining what our plans for this budget engine were, one of the younger guys at the shop piped up; “I’ve never heard of a harmonic balancer sleeve repair.”

Our culture has turned into one where the car owner will order two of the worn out parts and break out the credit card to pay for them. Gone are the days of repairing a worn out component when high performance is not the goal and the focus is more on budget. The realization that the  generation that used to patch tire inner tubes on the side of the road have almost all passed on, left us melancholy. It was clear that we needed to editorialize the simple procedure of installing a repair sleeve on a harmonic balancer.

The “How-To”

Make sure you have acquired the parts you need. In our case we wanted to change the cam, lifters, timing gears and chain, the timing cover gasket, harmonic balancer seal, and install the repair sleeve. Without having to look, we were almost positive that the balancer would be grooved after 126,000 miles of wear on the engine. As the parts came in, we stored them waiting for right moment to do the entire job.

Removing burrs and cleaning the surface is best done with 80-120 grit sandpaper. Notice the rubber between the rings on this balancer. No splits or cracks – the perfect candidate for a repair sleeve.

The entire operation is a simple prospect on a small-block Chevy. Simply remove the front pulleys and belts and expose the harmonic balancer. Like many of the early Chevy small journal crankshafts, our 283’s crank snout was not drilled and tapped for a retaining bolt. These balancers are held on to the crank snout by interference fit only. That is to say that the snout’s external dimension is slightly larger than the internal dimension of the harmonic balancer. When the balancer is pressed onto the snout, it results in a tight fit.

Some balancers have a center bolt that holds the balancer on to the crankshaft snout. Even with the retaining bolt, most harmonic balancers still rely on an interference fit for security. Removing the balancer is best done with a MAPP gas torch and a harmonic balancer puller. Applying heat to the balancer for thermal expansion helps relieve the pressure of the interference fit. The puller works to apply even pressure to pull the unit off of the crank snout. Prying a balancer will only damage the unit, and might even harm the crankshaft. The same is true when installing the balancer. Never pound the balancer on the crankshaft with a hammer or other tool. No good can come from striking the balancer to ram it on the crank snout.

The repair sleeve is an interference fit so you don’t want to remove too much material. Just enough to ensure proper installation and adhesion.

Once the balancer is removed, the damaged area is visibly noticeable. If the rubber dampening ring is still good and the outer and inner rings are still bonded tightly and show no signs of rotating, the balancer is a good candidate for a sleeve repair. Double check to make sure there are no cracks in the rubber absorbing material. Check the harmonic balancer metal rings for any cracks or damage as well. If there is anything suspicious, save the money on a sleeve and just purchase a new harmonic balancer.

Installing The Sleeve

Providing the balancer is still good and worthy of the repair, the next step is to clean the area. We used 120 grit sandpaper to remove any burrs or edges from the area where the groove had been cut and the edge of the balancer snout. The scuffed metal will provide a key hold for the bonding agent we use to hold the sleeve in place.

Red thread locker helps keep the repair sleeve from spinning on the balancer.

The repair sleeve is also an interference fit item. To help install the sleeve on the harmonic balancer, it is advisable to put the balancer in the freezer to shrink the metal as much as possible. The sleeve can be put in a pan of boiling water for thermal expansion. A heathy dose of red thread locker on the balancer snout will help provide initial lubrication, then bonding as it sets.

The repair sleeve is thin metal and can be damaged easily, so moderate striking of the wood is all that is required to seat the sleeve.

Place the sleeve over the balancer snout as far as it will go by hand pressure. Using a block of soft wood and a hammer, gently tap the repair sleeve over the snout until it reaches the lip at the end of the sleeve. The repair is complete and the balancer can be re-installed on the crankshaft snout with the appropriate installation tool.

Ensure the repair sleeve is fully seated then it is ready for re-installation.

The cost of the harmonic balancer groove repair will be under ten bucks, but you will be assured that the timing marks will be correct, or at least the same as they were prior. Chevrolet used many different harmonic balancers with timing marks in either 2-degrees or 10-degrees before the keyway. Using the wrong balancer may result in timing marks that are off by 8-degrees.

Parts Used:

About the author

Bobby Kimbrough

Bobby grew up in the heart of Illinois, becoming an avid dirt track race fan which has developed into a life long passion. Taking a break from the Midwest dirt tracks to fight evil doers in the world, he completed a full 21 year career in the Marine Corps.
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