4EFTE crank pulley?
- Thread starter Skalabala
- Start date
Texx
Super Moderator
Texx
Super Moderator
How many miles does the average 4E/5E-FTE owner cover during their period of ownership?
The engine isn't going to fall to pieces as soon as you drive off without using a stock harmonic damper pulley, but if you intend to keep and frequently use the engine for a significant amount of time then it's a no-brainer really.
To be fair the majority of people that run lightweight crank pulleys probably tend to run forged motors, which as Texx said, won't cover many miles and would have generally been balanced with this pulley. If you slapped a lighter pulley on an engine thats already done 120k miles who knows may what happen?
Texx
Super Moderator
Balancing the rotating mass of the bottom end won't make a lot of difference, it's the stresses acting on the crankshaft stretching and twisting it about that creates the problem. The vibration caused from this stretching sends a shockwave down the length of the crankshaft which, if at just the right resonating frequency, will cause further distortion of the crank. Without the harmonic damper absorbing the shockwave as it reaches the front of the crank, it'd then reverse and travel back down the other way in a similar fashion.
You only need to look at a suspended bridge during bad weather to understand why these resonating vibrations need to be absorbed by an external component.
You only need to look at a suspended bridge during bad weather to understand why these resonating vibrations need to be absorbed by an external component.