[blue2000s]

Originally Posted by Bladecutter

Actually, I recently learned that the Ford 4.0 SOHC V-6 engine in a lot of Ford Trucks (Ranger Pickup, Explorer, F-150, etc) also has a sort of IMS that drives the camshafts, similar to the Porsche.

Those engines also seems to have fairly high rates of noise and failure.
At least they have noises first to let them know something bad is going on.

They don't actually have an IMS bearing, from the little bit that I've looked into it, however. The problems that they run into are related to the tensioner assemblies failing, causing the camshaft timing to go out of whack, and then pistons meet valves at high speeds, causing massive damage, and big engine replacement dollars spent.

Sometimes, the tensioner assemblies fail in such a way, that the parts punch a hole either into the engine block, or the valve cover assemblies, which then sends shrapnel down into the engine, taking out other important parts.

Not good, either way.

This engine family was originally a pushrod engine, that was modified to accept a cylinder head design that had overhead cams. The original camshaft location in the block was used to house the IMS that feeds the chains to the cams in the cylinder heads. Just an under engineering example.

BC.

That's a good point, OHV engines drive the pushrods through intermediate shafts (or more correctly, the cam). The unusual thing about the M96 is that the engine was designed as OHC from the beginning and Porsche still chose to use one.