PORSCHE IMS BEARING RETROFIT SERVICES
Intermediate Shaft Bearing Explained
Inside your water-cooled Porsche M96 engine, you have a crankshaft that drives the connecting rods/pistons like everything else. The Intermediate Shaft is a tubular shaped part (see red arrow above)that resides just below the crankshaft, which drives it via sprockets and a double-row chain. It's purpose: driving the camshafts and the oil pump. Six-Cylinder Porsche Air-Cooled Engines(see left) have intermediate shafts since their birth, but none quite like this. The bearing that the sprocket-end of the intermediate shaft rides upon is a sealed steel ball bearing and when this seal shrinks, the grease inside leaks out causing heat and friction to build up leading to bearing failure. That's it. The IMS bearing fails and when it does, causes severe damage to your engine. In some cases, this damage is irreparable. This isn't a case of IF- it's a case of WHEN. What's worse, there's nothing you can do to stop this bearing from failing- but you can replace it before this happens.
Intermediate Shaft Bearing Exposed
Once half of the engine case has been removed here in this photo which shows a the IMS sprocket with chain. The IMS Bearing rides in the center of this sprocket. The flange is what is used to locate and secure the bearing assembly to the engine case.
The first step is always inspection. We run the engine and use a stethoscope to listen for abnormal noises. Next, we drain the engine oil and cut the filter open to inspect it for debris. Depending on what we find, we move forward with transmission removal.
Once the transmission and clutch assembly or drive plate is removed, the end of the engine case is exposed as shown here. Note the oil residue: the crankshaft seal is leaking and we'll replace it as well.
We then lock the crankshaft in the TDC position. Before the chain tensioners are removed, we lock the camshafts as well in order to prevent the engine timing from being disturbed during IMS service. This is a crucial step that cannot be overlooked!
The flange bolts are removed followed by the flange itself.
With the flange removed, the bearing is now extracted using special tools.
The bearing has been successfully removed from the intermediate shaft. The oil residue on the engine has also been cleaned thoroughly. The crankshaft seal has also been removed.
A new rear main seal is fitted with the Genuine Porsche seal installation tool.
Finally, the new IMS bearing and flange are installed. We also replace the 4 micro-encapsulated Torx-Head bolts(red arrows) recommended by Porsche to help prevent further oil leaks. With new components installed and oil leaks rectified, we're ready to