1098/1275 Crankshaft damper resonant frequency?

linearaudio · Post by **linearaudio** » Wed Nov 25, 2009 9:10 pm

cs I understand it, a crankshaft damper is tuned to a particular resonance for the engine it is fitted to. I noticed that my sons' Austin 1100 has a crank damper. Would this in fact be different to the 1275 one? The reason I ask is there are loads of 1275 engines in the local yard, but no 1100's, and if fitting a 1275 one to my moggy is not going to address the correct resonant frequency then is it not then a waste of time doing it?

Post by **PSL184** » Wed Nov 25, 2009 10:49 pm

The standard crank dampers as per factory were not really crank dampers ie tuned to a particular frequency. I would imagine all were standard but do very little to have any significant effect on NVH. You can buy kits (ESM) that are supposed to be tuned but I have no experience myself....

Post by **bmcecosse** » Tue Dec 01, 2009 11:18 pm

The early 1098 and 997 engines (and early 1071 S engines) had a 'two-piece' damper which worked well for me on my 948 rally engine. Until I fitted the damper (scrounged from an early 1098 in a scrappy) - it broke two cranks. After damper - no more broken cranks! However BMC soon changed to the more compact 'one piece' damper and standardised it on the 998 Cooper and all 1275 engines. It works! Don't ever build a 'modified' engine without fitting a damper!

Post by **billlobban** » Wed Dec 02, 2009 9:39 am

Had a look at ESM site couldn't find the damper and I' building a modified 1098

Post by **bmcecosse** » Wed Dec 02, 2009 9:56 am

They are hard to get now - some companies sell a solid steel pulley - this is NOT a damper - and although obviously stronger than the original pressed steel pulley -it won't help crankshaft life at all. Scrappy search! Or ebay. !! Maybe Minispares - or Minisport -I haven't time to look right now! But they won't be cheap.