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Yeah, probably chinesium, but for cranks in general that little strip of rubber in the damper is there to absorb vibration and lessen crank metal fatigue. Overtime rubber hardens. My car is about to have its 15th birthday (please no cards) so when replacing timing belts last fall I decided to include a new damper with fresh rubber. I mention this because I suspect this is something most people would never think about.
Can you help me visualize how the damper and rubber works to absorb vibrations?
Can you help me visualize how the damper and rubber works to absorb vibrations?
Its all black science, the province of automotive engineers. However, the crank twists a tiny amount with every power stroke and then it springs back. How much of this vibration is absorbed by the damper IDK but on other forums there's been people who have put sensors by dampers to study how much they heat up and they do heat up.
How important a damper is I'm sure varies from engine to engine but Mitsubishi used one and after 14 years of being cooked my thought was it couldn't be what it was when new.
Its all black science, the province of automotive engineers. However, the crank twists a tiny amount with every power stroke and then it springs back. How much of this vibration is absorbed by the damper IDK but on other forums there's been people who have put sensors by dampers to study how much they heat up and they do heat up.
How important a damper is I'm sure varies from engine to engine but Mitsubishi used one and after 14 years of being cooked my thought was it couldn't be what it was when new.
I imagine the rubber acts like a shock absorber connecting crankshaft to pulleys. It dampens the power pulses as rubber gets twisted back and forth. I think this resistance (from turning pulleys) helps counteract the crank's twisting at cylinder1 and a little from 2 before twisting goes other way.
Think more of a wrench hung by a string and struck. It rings like a bell. Hold it in you hand and do the same thing and no ringing. Soft flesh absorbs (dampens) the vibration.
To me, it looks like the problem with Manley crankshafts (forged and billet) is that the oil port compromised the integrity. I'll keep searching for other crank failures to see if it is the same.
Running a stock damper is definitely not the greatest idea on a built motor with deleted balance shafts. And then revving a 100mm crank to 8500 also wasn't ideal. There definitely contributing factors here. But as I stated in the other thread, we're asking a lot out of these little engines, they're not gonna last forever.
the sharp edge from the chamfer cut needed to be removed with a sanding roll then polished. That’s where the crack started. It’s just like a crack in your windshield, if it has no stress point it won’t crack.
read the “Cracked” article. Those holes look terrible sharp and not cleaned up. They basically cut the chamfer in with a cutting tool and did no grinding/polishing on the oil holes, If that crank was properly prepped it would not have failed.
