vibrating cank pulley

[austrian type-R]

I have a problem with one of my engines.

I started up an NSX today where many things were modificated. The crank pulley does vibrate up and down when the engine is idling. When I rec to 2000rpm or higher it runs smooth. I tried and aluminium crank pulley and a oem one, on both the same problem. Could it be the crank has a damage? The engine runned 20 minutes already and it sounds very nice, to bearing noise, etc.

I checked my other NSX and this engine has no vibrating problem with the crank pulley.

Anyone had a similar problem?

thanks

 

[Daedalus]

Are you certain it's the pulley and not the entire engine that's moving? If you can somehow affix a dial gauge to the engine you can turn the pulley by hand and measure its runout.

 

[KooLaid]

Is it an aftermarket pulley? Stock pulley with the rubber dampener coming apart?

 

[austrian type-R]

I tried 3 different pulleys, all oem and it is vibrating

 

[syam]

i would use a dial gauge on the crankshaft itself first to check if there is any noticeable runout...i doubt there would be a problem with crankshaft alignment as that would cause other problems with the engine running.

i would in addition check the crank pulley runout also, and recheck the pulley seat to ensure its critical dimensions. also, make sure the torque specs of the pulley are correct.