Re: Shaftless Throttle bodies
Posted: Sat May 06, 2023 4:52 pm
Crank was done at CMW Racing in California 20 plus years ago
Hi everyone. Just thought I would register since Jason has been telling me all about this site. And since he’s a great guy I figured you all must be too.
As for the failure on my engine there were many leading up to the rod knock. I had 3 timing belt failures - the last of which resulted in $5k in head work because the shop who rebuilt the engine refused to fix it. The final timing belt failure was when I finished work and parked in my underground parking garage. Can ran fine when I parked it. But when I went down to start it the starter just freewheeled making a zing type noise - no compression. I knew something was wrong right away. So I had it towed to the local Porsche dealer to take a look. The engine was under warranty and I could have taken it back to the builder. But since this was the umpteenth time I had brought it back to them I decided I wanted a fresh set of eyes to look at it. So I called the builder and asked if he would want to come up and watch as we took a look. He said I would have to pay for his time. I was not happy about it but agreed and told him we were starting at 8 am. He never showed. I even paid for the Porsche mechanics to wait 2 hrs because he kept saying he was coming before finally saying he wasn’t. So we started without him. When they took the plastic timing belt cover off there was a timing belt pulley just laying there. The bolt had sheared off. Because the block was from an 86 951 and my oil pump was from an 1989 951 it was required to space the pulley out with a spacer. The dealership printed off the technical services bulletin showing the procedure. What the engine builder did was try and use a stack of washers to space it out. Which might have worked if they placed them in the correct place on the block side of the nut instead of the pulley side. What they did was bottom out the threads on the stud and then put the washers on to space out the pulley. The nut on the stud was not snug to the block - there was a small gap as there are not enough threads on the stud or the hole isn’t deep enough. This meant the stud could vibrate and experience metal fatigue. Would also explain why my timing belts kept walking off, shredding one side, before breaking - 3 times. I had bent valves and the repair cost me $5k at the dealership. It ran fine for another few months before I started hearing rod knock. After that I hauled the car home and has sat on my lift since then as the whole event soured me on the 951.
