Underdrive Pulley Questions

[thstone]

Awesome, awesome! Thanks for all of the feedback and I just ordered the RSS UDP with the corrrect size belt from the guys at GSR.

[Ghostrider 310]

Originally Posted by thstone

Awesome, awesome! Thanks for all of the feedback and I just ordered the RSS UDP with the corrrect size belt from the guys at GSR.

You have to saw a "nub" of Aluminum maybe half inch for accommodation for the new pulley. That nub has a threaded hole right under it (I think it's under) anyway the point is DO NOT ruin the threaded receiver during nub removal. Apparently it's important for locking cams? I don't remember I just remember Jake saying do not ruin it which is simple if you are aware of it. The Aluminum cuts like butter too so no need for a grinder or aggressive saws all, I hand sawed mine.

[thstone]

Originally Posted by Ghostrider 310

You have to saw a "nub" of Aluminum maybe half inch for accommodation for the new pulley. That nub has a threaded hole right under it (I think it's under) anyway the point is DO NOT ruin the threaded receiver during nub removal. Apparently it's important for locking cams? I don't remember I just remember Jake saying do not ruin it which is simple if you are aware of it. The Aluminum cuts like butter too so no need for a grinder or aggressive saws all, I hand sawed mine.

Ghost - thanks for the installation tip! Sometimes knowing what NOT to do is just as important as knowing what TO do.

[seventythree]

Originally Posted by Ghostrider 310

You have to saw a "nub" of Aluminum maybe half inch for accommodation for the new pulley. That nub has a threaded hole right under it (I think it's under) anyway the point is DO NOT ruin the threaded receiver during nub removal. Apparently it's important for locking cams? I don't remember I just remember Jake saying do not ruin it which is simple if you are aware of it. The Aluminum cuts like butter too so no need for a grinder or aggressive saws all, I hand sawed mine.

The hole is for the pin that locks the crankshaft at TDC (or 180 degrees from it), and is not threaded.
The point is not to cut the boss off completely; cut enough the clear the smaller UDP, but leave some to accomodate the locking pin.
However, keep in mind that the locking pin cannot be used once the UDP is on there. So, if you need to do anything that requires the crankshaft to be locked at TDC (such as replacing the IMS bearing), do it before you install the UDP. Otherwise, you must devise an scheme to lock the crankshaft from the flywheel end.