what size is a stock hamonic balancer for a sbc

by Prof. Ava Franecki Published 3 years ago Updated 2 years ago

Here are a few sizes and what they fit, from the SBC Interchange manual: 6 ¾ x 1 3/16 350. 6 ¾ x 1 11/16 267, 305. 8 x 1 ½ 350. The 305 "thick" balancers have the timing mark located differently on the balancer, so the timing cover/tab must match to use that balancer.

Full Answer

What is the diameter of a harmonic balancer?

Harmonic Balancer, 6.750 in. Diameter, Chevy, GMC, Pontiac, 5.0, 5.7L, Each 8", 350 ci Harmonic Balancer, Harmonic dampner, Internally balanced, Fits Most Internally Balanced SBC's Harmonic Balancer, OEM Replacement, Chevy, GMC, Oldsmobile, Pontiac, V8, Each

What's the difference between a 8 inch and 8 inch balancer?

The larger mass of the 8" balancer is better at canceling crank harmonics which increase w/stroke size---prolonging crank life.The smaller balancer is better for acceleration w/less weight and smaller OD. Look back at what Chevy always put on their high performance small blocks; the 8" one.

Should I lighten my harmonic balancer?

“It sounds counterintuitive when the trend is to lighten everything, but harmonic balancers weigh what they do for a reason. A too small or light damper will not do as good a job controlling torsional vibration. Vibration will pass through the engine where it can lead to lost power, premature bearing wear, and inaccurate timing.

What size timing chain balancer for 350?

Good old double roller timing chain is the way to go From what ive seen , chevy used the bigger balancer on their more perf. orientated motors....Dont use a balancer thats breakin down in the rubber area!!I think you need to rebalance if you use the 8'' job.. 350 balancers are neutrally balanced, so 6.75" or 8" shouldn't matter.

What size is a Chevy 350 harmonic balancer?

Does the size of the harmonic balancer matter?

No matter what anybody tells you, size does matter when it comes to the harmonic balancer you use on an engine. Putting an incorrectly-sized balancer on an engine will do more than just cause it to not reach its full performance potential … it will cause serious damage to the rotating assembly.

How do I know what harmonic balancer I have?

The most common symptoms of a bad harmonic balancer include:Engine Vibrations. The harmonic balancer's job is to dampen vibrations applied to the crankshaft. ... Noticeable Harmonic Balancer Wobble. ... Unusual Noises. ... Illuminated Check Engine Light. ... Visible Wear or Damage.

Does a harmonic balancer increase horsepower?

Adding an upgraded harmonic balancer is a great way to keep your engine from having serious issues as horsepower increases. LeBarron goes a little deeper into the issues a stock harmonic balancer will experience as you up the power.

Is a lightweight crank pulley worth it?

On a well maintained engine with bolt-ons or low amounts of boost like what most owners probably run, a lightweight aluminum crank pulley will not have any life threatening consequences. The engineering reasons are that most modern engines have a short (increasingly strong) crankshaft operating under 8,000 RPM.

Does damper size matter?

As a rule of thumb, the longer the stroke and greater the torque, the larger the diameter and mass. However, larger dampers can affect the acceleration and revving ability of an engine, so the right diameter and mass can help you strike the right balance.

Can you start a engine without a harmonic balancer?

The harmonic balancer is essentially part of the crankshaft pulley. And because the belts that go around the crankshaft pulley run all of the car's accessories, without the harmonic balancer you'd have no air conditioning, no power steering, no alternator and no water pump.

How do you install a harmonic balancer without tools?

1:5511:14How to Install Any Harmonic Balancer "With A $2.00 Homemade Tool ...YouTubeStart of suggested clipEnd of suggested clipLet's take a socket. And lightly tap it in until you can start a boat. Tool. You do not want to hitMoreLet's take a socket. And lightly tap it in until you can start a boat. Tool. You do not want to hit this very. Hard like taps won't hurt. Big top soil okay. So here's the original bowl.

Can harmonic balancers be rebuilt?

The good news is, the harmonic balancer can easily be repaired with a kit that usually retails for under $10.

Is a damper the same as a harmonic balancer?

A harmonic balancer (sometimes called crankshaft damper, torsional damper, or vibration damper) is the same thing as a harmonic damper except that the balancer includes a counterweight to externally balance the rotating assembly.

What does an upgraded harmonic balancer do?

The function of the harmonic balancer is to reduce the amplitude of the torsional vibration peaks to an acceptable level. Most OEM harmonic dampers are not designed to cope with the rpm and BHP levels experienced in competition. That is why racers must consider a high-performance damper that is fit for purpose.

What does Super damper do?

In contrast, the ATI Super Damper employs a combination of O-rings and a unique, full-captured inertia ring to dampen harmful crankshaft vibrations. This configuration allows the damper to actually absorb crankshaft harmonics over a wide rpm range.

What size balancer is used on a 400 small block?

The 400 small-block, with its 3.75-inch stroke, used a unique 8-inch balancer with external balance weights. Also, as a group, trucks tended to use the larger balancers because they were intended to carry cargo loads or be used for towing, operating cycles that over time impart extended stress on the engine's bottom end.

Why do all 350s have an 8 inch balancer?

Nearly all 350s came with an 8-inch balancer because of their relatively long stroke. An 8-inch balancer was used on the short-stroke, 3.0-inch-stroke, 302 Z/28 engines because those mills were intended for road racing. The 400 small-block, with its 3.75-inch stroke, used a unique 8-inch balancer with external balance weights.

How much does a shaker table cost?

A shaker table costs about $20,000 and the cryo freezer around $75,000, so in the past it cost an arm and a leg to get parts cryogenically treated. But Mondello says he's now able to shake and freeze a crank for around $275.

How much can a 350ci crank deflect?

According to Chevrolet sources, "Tests have shown that the crankshaft in a 350ci racing engine can deflect 0.3 degrees at 8,000 rpm.". Other authorities claim crank deflections of as much as 2 degrees. When the torque load on the crank is released and the crank untwists, vibrations occur.

What happens when the torque load on the crank is released?

When the torque load on the crank is released and the crank untwists, vibrations occur. At certain engine speeds, the torque inputs become synchronized with the vibrations in the crank, resulting in what's known as resonance.

How much does Mondello get for a piston?

If piston life due to excessive heat becomes a problem, it may be easier to get the pistons high-tech coated. (Mondello gets $45/piston for ceramic top coatings, dry-lube skirt coatings, and oil-shedding bottom coatings.) Also pay attention to the piston-to-cylinder wall clearance.

What is a short stiff crank?

A short, stiff crank is less affected by torsional vibrations than a long, flexible crank. Within a given crank length (a crank for the same engine family), stiffness is a function of stroke length, the amount of main and rod journal overlap, and crankshaft material.

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