So, you’ve been told or have read that “you need an IMS Bearing Upgrade”. Great, but what exactly is that and what does it mean for your Porsche? Well, here’s what you need to know...
What is a Porsche IMS Bearing?
The IMS is the Intermediate Shaft and the IMS Bearing is a support for this shaft on the flywheel end. This IMS design was used by Porsche in all M96 and M97 engine cars: flat 6 boxer engines found in Boxsters, Caymans and 911s built between 1997 and 2008.
The intermediate shaft’s job is to drive, although not directly, the camshaft from the crankshaft. The bearing supports this and, if worn, or it fails it can cause quite significant and serious damage.
So, put simply, the IMS and the IMS Bearing are vital components in the engine of your M96/97 Porsche and it’s not good if they go wrong!
What happens if my Porsche IMS Bearings go wrong?
Whilst the Internet forums do exaggerate the rate of IMS bearing failures it is a very real problem.
The most common cause for the IMS bearing to fail is due to the high load pressure on the standard roller bearing OEM part coupled with a lack of sufficient lubricant. In addition, causes such as spalling, whereby the surface of the bearing becomes weakened and fractured can occur over the working lifespan of the IMS bearing.
The resulting IMS Bearing failure could cause the engine’s timing to alter and it is highly likely that piston / valve contact will occur. If this case does happen, then the engine will require a comprehensive rebuild.
In the worst case it is entirely possible that cylinder head damage, liner / block damage will subsequently occur. This can be catastrophic and effectively write off the Porsche engine as an uneconomical repair.
What are the signs of IMS Bearing failure?
Essentially there are three key signs that you may need to take your Porsche in for an IMS Upgrade. These are:
- Metal fragments in the oil filter (usually found when you carry out the regular Porsche oil change).
- Oil Leak (usually the leak is visible from the underside of the engine where the engine and gearbox join).
- Loud knocking noises coming from the back of your Porsche.
When you discover any, or all, of these problems, it is vital that you book your Porsche in to a Porsche specialist straight away and have the IMS Bearing checked to see if you need an upgrade. It is highly advisable not to drive or even start the engine if it can be avoided!
Unfortunately the above symptoms are not fool proof. The OEM IMS bearing can potentially fail without warning at any time.
What IMS Bearing do I have and can I have an upgrade?
Porsche have installed three variations of the IMS bearing in their M96 and M97 engines. Dual row, single row and the final revision a larger design of the single row fitted in the later M97 engines.
Both the small single and the dual row designs can be replaced with the transmission and flywheel removed from the engine. The larger single row design requires the engine to be fully dismantled to change.
Statistically the smaller single row bearing found in later Porsche 996 models, 986 Boxsters and early 997 / Cayman models is the most prone to failure. However, we at AMS Porsche have dealt with failures across all three variations of Porsches standard IMS bearing.
If you would like clarification on which IMS bearing is installed in your Porsche and suitability of upgrading please do not hesitate to give us a call, we will be happy to explain all the permutations.
What IMS Bearing Upgrade does AMS Porsche use?
There are many different aftermarket IMS bearing options available. AMS Porsche install the EPS cylindrical bearing upgrade which is a direct replacement for both the standard dual row bearing and the smaller single row design. Since EPS started to sell the Cylindrical IMS Bearing in 2013, they have sold over 5,000 units in total, and have NOT had a report of a single failure.
Please visit the EPS website to see the full specification.
Here at AMS Porsche we are independent Porsche specialists that have carried out many IMS Bearing upgrades for our customers, some were in much worse shape than others, but that was no barrier for us. Our highly skilled and experienced Porsche specialists are able to tackle any state of IMS bearing upgrade, we know it gives our customers great peace of mind that their cars are being taken care of.
If you would like to have a chat about having an IMS Bearing upgrade on your Porsche, just give us a call and we’ll be more than happy to help.