Underdrive Pulley Install Guide

[Topless]

I believe jmatta is right. The boss in the casing that must be cut down is a top dead center locator. You align to TDC and slip a retaining tool through the stock pulley to hold the crankshaft in place. It is useful when changing timing chain tensioners to keep everything aligned so don't cut it all the way off. There are other ways to fix the crankshaft at TDC but this is a quick way that techs are familiar with. On one car in our club the casing boss was completely cut off and the Porsche techs had to get creative as they could no longer use the tool.

[clickman]

Fig. 25 confirms it's for TDC.

http://www.pelicanparts.com/techarticles/Boxster_Tech/Disc163/BoxsterTech-163.htm

[jmatta]

Very good visual, indeed. Do you think the point is strong enough to hold so you could loosen the crank bolt? The only experience I have is that is remotely close is the tool that holds the pulley for removal in an older air cooled 911.

[TroyN]

It is strong enough. The bolt is on there way tighter than the fan/alt nut on the air-cooled 911s incidentally. (just did this mod today)

[CapDunn]

Why not remove the stock pulley with air tools?

[TroyN]

Originally Posted by CapDunn

Why not remove the stock pulley with air tools?

There's no room in there. You could do that if you dropped the engine.

[syncspeed]

It is strong enough, I just cut a large hex key to fit in the hole and it worked like a charm. You will need a large breaker bar and a 24MM socket to get it loose.