crank or acessory pulleys

[tonytony]

is their any downfalls for removing the crank pulley and replacing it with a lightened? Or should i just get the underdrive pulleys and be done with it?

[bmw332i]

Just get the underdrive pullies. They're probably cheaper than a crank pulley, and still yield pretty decent gains on an s5X engine. Turner has them on sale now for $250. And you won't have to worry about the crank being out of balance....

[tonytony]

i've looked around on bimmerforums and the risk involved in changing over to the crank pulley isn't worth it to me. Of course there hasn't been anyone ever who's engine exploded with one, just the fact that it could happen is enough deter me. tahnks

[Beej '86 325es]

i've looked around on bimmerforums and the risk involved in changing over to the crank pulley isn't worth it to me. Of course there hasn't been anyone ever who's engine exploded with one, just the fact that it could happen is enough deter me. tahnks

Those URI crank pullies are for sale on Bimmerforums all the time, people really have problems with them. Plus you can't run a lightened flywheel with it.

I'm sticking with underdrive accessory pullies on my engine build.

[Mot]

tony just search bimmerforums, there is a set of uuc underdriver pullies for 140 shipped on bimmerforums right now.
I got a set of KO underdrive pullies for 100 shipped.

[tonytony]

yeah i know, tom, i'm going to buy it from that guy

[matt]

Those URI crank pullies are for sale on Bimmerforums all the time, people really have problems with them. Plus you can't run a lightened flywheel with it.

I'm sticking with underdrive accessory pullies on my engine build.

Crank pullies that eliminate the harmonic damper are a major cause of oil pump nut failures. They may also cause early bearing wear and any number of other issues.

This has NOTHING to do with lightweight flywheels. A dual-mass flywheel is not there for the engine's benefit, it reduces drivetrain NVH.

[tonytony]

well i guess it's not that big of a deal, i'm running a lightened m20 single mass flywheel anyway. I just made a purchase for the UUC underdrive pulleys

[02stu]

I didn't think you could even start your car without a harmonic balancer? If so you are not only putting stress on your oil pump you are also putting stress on your crankshaft brearings.

[matt]

I didn't think you could even start your car without a harmonic balancer? If so you are not only putting stress on your oil pump you are also putting stress on your crankshaft brearings.

The URI crank pully replaces the trigger wheel, but does away with the actual part that damps the vibrations. It's not a good thing, fasteners like to unfasten themselves when they vibrate like that.

[tonytony]

I took mine out and put it back in to do someting i forgot, does it have to be put back on with the same position as it came out with?

[matt]

The stock crank pulley/harmonic damper only goes on one way.

[tonytony]

oh yeah duh!!!!! :drink: