Information on Harmonic Balancers

[pastaroni34]

Guy,
I have had a couple of people ask me to make crank pulleys for the BMW S14 engines used in the E30 version of the M3. These engines feature a harmonic balancer on the front crank pulley. I have found very little information on if this part is truely necessary. I understand how the part works, and that it can help reduce torsional vibration in almost any engine situation. I was just wondering what your take on it is. I have not seen any definative tests to prove one way or another. Many people have "heard" of having crankshaft failures without one but no one knows for sure.

What really bugs is me is that all the previous versions of this engine, the M10 and such that go in the 2002 and 320 bmws do not have balancers and their cranks are very similar. Also, why don't our Fiat and Alfa engines have them?

Thanks for your help,
-Jason Miller

[mandic]

I know it doesn't answer Your question, but anyway, everything You need to know about engine balancers, comes handy

http://www.autozine.org/technical_schoo ... mooth1.htm

thank you

Ziga

[Julian]

Why don't our Fiat and Alfa engines have them?

Thanks for your help,
-Jason Miller

Jason - as far as I know all of the recent Fiat and Alfa engines come with harmonic dampers as standard, this goes back more than a few years. I can't vouch for Guy but we retain them on our engines as standard.

Julian

[Guy Croft]

The thing is there to reduce torsional stress in the crank. And yes the Integrale has one, probably other similar late generation engines too, the crank front pulley with the micro V belt drive is such a thing.

I don't see the point of using them on that engine or any other TC, flat plane crank with internal balance, super strong. I mean, I would not remove the item from a Rover V8 or Jaguar 6 cyl or maybe Mini 850, but the TC ran for nearly 20 years without one and suddenly it needs it? Maybe it was added because, on the later units there was an additional load on the crank nose from the Lanchester balancer shafts.

If anyone has broken an Integrale crank or sheared a flywheel from removing it I would like to know about it quite quickly!

GC