Cab in intensive care

For those of you that may be interested, I've posted pics of my 2001 cab which is undergoing some major surgery to the chain tensioners and pads. Not cheap. Of course, while we're in there, the IMS bearing will be replaced, the clutch, the AOS etc etc etc. We notice some seepage around the IMS area and the valve covers were all gooed up as well, so a cleanup is in the works. Interestingly, the bearing is a dual row, not what we expected in a 2001.

You can't "expect" anything on a 2001 when it comes to the IMS. It's a crap shoot.

Just went through the same on my 2001 (120k miles). It was also a dual row bearing...spinning smoothly and freely when replaced. The bearing was filled with engine oil (a surprising amount), but seem to be in good shape. -Shawn

What prompted you to do the chain tensioners and guides? I think it's a good idea on high millage motors, I've just not decided what "high millage" means yet.

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It wasn't something that I just woke up and decided to do, believe me! The indy put the car on the scope and the readings on the cam variance were beyond the range of normal apparently. This seemed to point to the pads on the tensioners as being worn. In fact I saw the pads in a video sent to me, they were worn and grooved, so replacement of pads at minimum, the entire set of tensioners at worst. So, at worst it is. Interestingly, the car has only 112k kilometers on it, so not really high mileage (in my mind anyway). There was nothing in the way it drove that signalled to me that something was amiss. In fact, I checked this forum and I couldn't find too many instances of tensioner pad discussions. You would think it's more common. As an observation, while sitting on the palette, the engine is much taller than I would have expected. No wonder the newer cabs have that unsightly bump in the caboose with their bigger 3.8's. The dual row bearing was a surprise to me, since I thought the 01's were single row. It was actually in good shape, no signs of failure, but you can see there was some leaking around the opening of the block.

Vicious, I've recently stopped daily driving my car. After sitting for a week or so, I got a rather unpleasant start up noise. I'm not positive of the origin, but draining of oil from the compromised seals of the IMS bearing and bleed down of pressure in the chain tensions both seemed like possible issues. The labor for each overlapped so I had both done. I did not have the pads replaced. I know they wear, but I'm not seeing any particles from the wear in my filter inspections. Shawn

As a reference, at 200K miles, one of the variocam pads wore down enough to break off and jamb between the chain and the sprocket. This took one 6 exhaust valves and made the owner trade his car is for a new Boxter. I bought it and fixed it. The pics are on the build page on the Canadian forum.

^^^^ Imre's fix is one of the best threads that I've followed and worth looking at. Again, I'm surprised the tensioner and pad issue hasn't come up more.

From one of the other threads, " "...2005 c4s tiptronic, IMS failed at 55k miles. On disassembly i found that the ims drive chain tensioner paddle had broken. No other apparent damage...." some of you expert wrenches can weigh in on this, but maybe the pad collapse on the tensioners are more at root of ims bearing collapse than the bearing per se? the pads are only plastic and would seem to be a weak link. In addition Imre's fix was about the pads breaking up and falling into the chains.

When did you change the rear main seal. The originals had round indents, new = square.

I didn't know that, but I had them done in late 2004 by the dealer. No charge at the time. Oddly, they did nothing about the IMS bearing at the time. I guess those issues weren't a big deal yet. I certainly was unaware until after that.

Apologies for the large pic. The camshafts laid out on the table. You can see one of the tensioners in the middle of the table. If you zoom in, you can see the wear marks on the plastic pads which caused the variance in the cam numbers. This is how we got to where we are today. So, waiting for the tensioners to arrive so we can re-install everything. All engine components are good, no scoring on walls, no debris...whew.

I don't think those pads are worn enough to cause that issue. The solenoid or the actuator might be faulty.

Ok, so as a follow up, I finally got the cab back today after a pretty comprehensive preventative maintenance regime. As Imo surmised, the solenoids were faulty on the tensioners which precipitated this whole fix. So now, they've both been replaced, new RMS, LN bearing by a legitimate, qualified installer here in Richmond, AOS separator, clutch, oil sending sensor and valve cover gaskets. Phew. The clutch action is so fast and light now, what a difference! I'm good to go. Car feels great.

What did that adventure cost you?

just the other side of 8g including all taxes (this IS Canada). For amusement, this is more than the total cost of my first 3 cars when I was a kid. Of course at that time (1974), a Porsche was only a distant fantasy.