The amazing V8 engine of your 928 can completely fail if you don’t address this issue. This is known as the flexplate problem.
The flexplate problem causes the crankshaft to be pushed forward, which leads to rapid wear of the axial crankshaft bearings and eventually the crankshaft and engine block are ruined. The crankshaft essentially bores its way through the engine block. It’s a matter of only 3 to 5 mm, but that’s enough to cause serious damage.
Many designs and very good products have already been made for this. We focused on pure functionality and concluded that all other designs make one mistake. They create a clamp from two halves on a shaft that consists of three segments. The clamping force on the three segments is never equal. A simple vector force calculation proves this. Even Porsche’s original clamp was designed with a single bolt and two segments.
The clamp we designed is also relatively small to keep the weight low. This keeps the centripetal forces that pull the clamp apart smaller.
This new clamp is made of 3 circular segments that fit perfectly around the original flexplate clutch sleeve. We use 3x M8 very strong 12.9 hex socket bolts to tighten the clamp to 60Nm. With this new clamp, the problem disappears completely. It holds the driveshaft as the Porsche engineers intended.
Below is a photo of an average 928 automatic, before and after loosening the original clamp. You can (with some effort) see that the visible part of the splines becomes shorter. The clamp has shifted slightly after loosening the bolt.
In our opinion, this is the best solution at the lowest price. Installation is fairly simple, and you can wait for it with us. For models up to ’86, it takes about 2 hours. For later models, the exhaust must be removed first.
Suitable for all 928 models
Porsche 928, 928S, 928S4, GT, GTS
Reference number:
92242125500, 92211604103
Tags:
Flexplate problem, Porsche 928 engine problem, wear, torque tube
