Crankshaft, crank pulley, flywheel and clutch pressure plate balancing

Another day, another thing out of the way. Check out the gallery at the bottom of the post for images. 

For this „thing“ I actually had to leave the borders of my homeland and travel to a neighbouring country to get my rotating assembly balanced. No does it where I live so I packed put everything in my trunk and hit the road.

When I say “rotating assembly” what I mean is the stuff in the post heading, the crankshaft, the crankshaft pulley, my blacktop flywheel and the clutch pressure late from my recently acquired AISIN clutch kit (if you want a replacement clutch kit from AISIN for the blacktop flywheel order AISIN part number KT-100a or just KT-100)

So, do you need to have your rotating assembly balanced if you are doing a mild or stock rebuild. Short answer: No. Will you have benefits? Short answer: Yes.

What is balancing?

Ever replace your tyres and had your wheels balanced? Well, that’s it. As the name suggests, balancing means creating an equal distribution of mass across a rotating object. If your wheel isn’t balanced it will wobble and you will have a lousy time driving your car. The same thing is with crankshafts and flywheels.

Why should you balance?

„My car is running fine and I have never balanced my crankshaft or flywheel?“.That of course is true, since the crank, flywheel and other rotating bits are balanced at the factory during manufacture.

If you take a look at your crankshaft, flywheel or crankshaft pulley you will see that all of these things have holes drilled into them. Those holes have been drilled in the factory and their purpose is to remove excess mass in order to create an equal distribution of mass. This means your crankshaft, flywheel, pulley and some other bits come balanced from the factory.

So, if your crankshaft is already balanced, why should you balance it some more? Balancing like most other things in the world has varying degrees of accuracy. During mass production of vehicles, like with any other business, time is money. Since the 4AGE isn’t a hand-assembled million dollar super-car engine its rotating assembly has been balanced to an extent determined sufficient for its application. Time is precious and the factory can’t have its employees spend too much time balancing a single crankshaft. This is why stuff at the factory is balanced to within a few grams. Aftermarket balancing in specialised machine shops is often done to within one tenth of a gram.
What are the benefits? Those who have driven the same engine with and without additional balancing done claim that it’s quite an obvious difference. Balancing significantly reduces vibrations and creates an engine that is far more smooth, spins better and is a greater pleasure to drive. Well, I did it, but wont get to taste the benefits until I finally fire this baby up.

What should you balance?

There are two types of balancing. Static balancing and dynamic balancing.

Dynamic balancing means spinning an object at a relatively high speed and have the machine determine where and how much weight should be removed. Crankshafts, flywheels and pulleys need to be dynamically balanced because they spin, just like wheels.

Static balancing means removing weight without spinning. A component is weighed and then weight is removed from certain areas until a desired weight is reached. Connecting rods and pistons are statically balanced. They are weighed and then subjected to material removal until all match the weight of the lightest piston/conrod.

So, what should you balance? Well everything you can afford. Static balancing can be done at home, while dynamic balancing requires special machinery that often costs a fortune.

Balancing just the flywheel or the crankshaft will have benefits that will be hard to notice. Balancing the pistons and connecting rods alone also won’t yield noticeable benefits. Balancing the crankshaft and flywheel along with the pistons and connecting rods will yield the best results. It will create a smoother, better reving engine. Balancing is especially important if you want to go for high rpms or increase the power significantly.
Flywheel balancing should be done with and without the clutch pressure plate attached. This means that the flywheel is balanced separately but also balanced as a whole together with the pressure plate.

p.s. I derusted and painted my crank pulley. Didnt want to make a video. Sick of rust removal and painting videos.

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