If the flywheel on the existing engine is itself balanced you don't need to have the new one match balanced (just balanced). If it is balanced as a unit with the crankshaft, then you should see witness marks to show the proper orientation. (Sometimes these are hard to see though)

If they are balanced as a group, then you need to "match balance" the new flywheel to the existing one. This will essentially put the identical amount of misbalance into the new flywheel as existed in the old. Then you need to install the new flywheel in the same orientation as the original,which is why you make your own witness marks on the crank and flywheel before removing.

I've heard that a majority of flywheels do not require match balancing...but you can bet that if you don't do yours it will surely be one of the ones that require it. It's just Murphy's law.

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Current Stable

• 380SL (diesel)
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