Q – On my 74 911 the crankshaft pulley fell of the end of the engine at about 110 miles an hour! The red light came on and the engine felt like the turbo kicked in. And it is not a turbo. What a thrill.

When I looked at the pulley I can see a hole where a pin would have gone through it and into the crank but there is no hole in the crank. What gives? Can I just bolt the pulley back on without the pin.   Randy

A – Randy, the pin hole mushed over when the pulley came loose. First the good news: The crankshaft is hardened and it is probably OK unless you mess up trying to get that pin out. This process will be time consuming since it involves removing the exhaust and rear motor mount bracket just to gain access. Once you can see what you are doing you have to find the hole and the pin. I use an abrasive Roloc disc to clean away the metal that was transferred to the crankshaft during the failure.  When you find the remains of the pin, start with a small drill and begin drilling it out. Your ace in the hole is that the crankshaft is hardened and the pin is not. When you get the hole large enough, put a screw in it and pry it out.

So you have saved the crank, you need a pin, and the pulley is damaged. Smart Racing products makes a replacement pulley out of billet aluminum that comes with a new bolt and sells for about $120.00. The pin is the same as a VW beetle main bearing dowel pin that you can get from any VW shop. The crank will need to be smooth and true before you bolt the pulley on and judicious smoothing with the Roloc disc has worked well for me.

About that “turbo boost” effect? The fan and alternator take about 20 horsepower to run at that speed when the failure occurred. You felt the difference between gross horsepower and net horsepower. As far as running the engine without the pin by just bolting the pulley back on? The pin is for alignment of the timing marks and the bolt secures the pulley. You could have bolted it down snug and driven it but then the crank could have been damaged more than it already was. In a third world country, this would have gotten you out of the bush but it is better that you didn’t try it.  –MC

CategoryMasterCylinder, MC911