Thread: damping on a crank pulley??

hi guys. i bought these the other day



but ive been told by other mechanic mate that cause they have no damping bit on them that they'll damage my crank. can anyone shed any light on this please??

thanks ross

There are pros and cons. Make up your own mind:
http://www.sr20-forum.com/495343-post21.html

Search the forum for "harmonic damper" for more results.

Heres a thread I started about this ...
http://www.sr20-forum.com/vvl/11516-pulleys-ve-safe.html

cheers for the info guys.

so it seems its safer to run these on an 8cw rather than a 4cw

mines a hiport p10 engine so should be 8cw right??

In my opinion 8cw or 4cw has pretty much nothing to do with it. Why it was brought up in eggman's thread is beyond me. Yes harmonics are changed between 8cw and 4cw cranks but you'd be hard pressed to definitely know if one is more prone to exaggerated torsional bending harmonics than the other.

The 8cw versus 4cw crank argument is about rotational mass versus 3rd order (or is it second order?) rotational balance. The 4cw cranks weigh less and have less moment of inertia. The 8cw cranks weight more, have a larger moment of inertia, but are completely and fully balanced in 1st, 2nd and 3rd order rotational balance dynamics. This has nothing to do with torsional bending harmonics.

argh so difficult to decide lol

think i will just fit them. i have another 2 engines at home so if it does go wrong i'll just go all motor and start from the beginning. thanks for your help. really appreciate it

The worst that could go wrong is that your crank snaps. So far, I've never heard of a report of an SR20 crank snapping. The other thing that could go wrong is that you might experience accelerated rod bearing wear or failure. I can't say how likely that is, but I typically lean towards "don't worry about it too much".

it will be fine

i was told that u will encounter bearing wear faster with the solid crank pulley that the dampered ones..... the rate i was told would estimate up like

dampered pulley.... 10yrs
solid pulley......7yrs

as i said these arent the actually life but just to give u a ruff idea what the wear would be like

Just remember that the timing marks are off by 3-4*. These are the 1st gen GSpec pulleys.