underdrive pulley install question
 

Gang, quick question.

The pulley has a keyway that locks it to the crank. The crank is held to the transmission by the clutch which then goes to the wheels.

So, if one leaves the car on the ground for install, in gear with the parking brake engaged, the crank should not spin when loosening or tightening the crank bolt.

Can someone tell me if I'm missing something since all the install guides indicate that the crank must be held by external means when doing this job.

Thanks

http://986forum.com/forums/diy-project-guides/23057-underdrive-pulley-install-guide.html

May help...

thanks. I posted in there as well, but so far no one has an explanation.

My thought is placing all of the torque on the crank keyway may not be the best practice.

It might be better (per the instructions) to have the torque force carried on an external bolt that transfers the load to the engine case to avoid loading up the crankshaft and/or drivetrain.

I have installed 3 UDP's and used the bolt to hold the pulley each time. I can't say if the other approach would be ok to use or not.

Well really since the bolt is screwed into the crank providing only friction onto the pulley, it shouldn't stress the keyway much.

that said, our friend Jake Raby has shared with me that my method would be detrimental to Dual mass flywheel. Hence I'll use the tdc boss and strap wrench.

Thanks!

Taking off the pulley the TDC pin can be used to break the bolt loose. There isn't a key only a positioning pin, which I don't think you can damage while loosening or tightening the bolt. Most UD pulleys come with a tool to hold the pulley while tightening and or removing at a later date.

Mine didn't but no big deal. All installed, only took a bit over an hour. All good