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Checking the ims bearing (c4s project)

Harv

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18 Sep 2014
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I have the engine out of a 2002 c4s for work relating to a misfire on cylinder 5 (coils and plugs renewed and it persisted but now with the heads removed it turns out to be a burnt exhaust valve, phew ) and while I'm in here want to check the ims bearing for play.

Is there a procedure for this someone could either point me towards or describe. I've looked at the pelican parts website which has a detailed set of instructions for replacement but initially I only want to have a feel for play (if this is possible).

I can say there's a lot of solid goo on the ims cover but no oil leak and also the rms is dry ( both look to have never been touched before).

Thanks :)
 
I would just go straight for a replacement if you have the engine out.
 
Thanks for those links

I've noted Hartech's comments on just replacing it with the porsche bearing (does anyone have a part no or cost for this??) but I'm tempted to size it off the old one if I remove depending on testing in situ.

The car has 110k and no signs of metal in the oil filter or the vario cam solenoid mesh filters in the heads.

It's still on its original clutch, worn down to the rivets now though!
 
There isn't a part number for the original bearing as it only comes from Porsche fitted into an IMS. You would be best to to remove your current one and measure it, then order one with no seals. The bearing post is also a weak point but an upgraded post is not available off the shelf anywhere, although Hartech can supply and fit both bearing and upgraded post if you can supply your IMS to them, this would require you splitting the crankcase though.
 
Cheers
As I have the heads off and the chain ramps removed I will pull the ims bearing bolt nut and cover and have a look inside. I'm sure it's probably quite happily being lubricated by oil after 110k!

I'm not sure what caused the burnt valve but upon stripping and inspection all the exhaust valve to seat contact faces look to be in poor condition. Perhaps the car has been run on cheap and nasty 95 octane fuel?

All the cylinder bores look in great condition so this will only be a top end overhaul.

Fuel injectors are removed for ultrasonic cleaning and flow testing.

Updates as we go
 
The heads are finally clean after a day of scrubbing! The exhaust ports we're heavily carbonated leading me to believe that possibly the air injection pump isn't working (something else to check).

IMS bearing cover removed to find a single row bearing with the external circlip (2002). The outer seal is intact and you can feel a slight amount of play but spins freely with no noise. I'm very tempted to leave it be...

Parts are on order and awaiting new exhaust valves so that a full valve regrind can be done (by hand of course) and new valve stem oil seals will be fitted.

The valve springs and lifters look in good condition so they are going back in, I may have the spring rates checked to confirm this.

Fuel injectors have been cleaned and checked out spot on for flow and spray pattern.

:D
 
That is my sticking point at this moment.

Does anyone have a set of IMS bearing replacement tools they'd be kind enough to lend me with a deposit? Pm if so...

Once it's removed I'll get onto SKF bearings for a replacement.


TIA
 
I may make the tools :)

A few pictures

Bumpers off



Condensers and rads need replacement



Rear end and engine removal



Due to low compression on cylinder #5 (60psi) and the heaviest clutch pedal I've ever felt the engine was removed for further investigation



The clutch is 12 years and 110k young!



Ancillaries removed, starter makes a screeching noise at times.



Water pump was leaking and the bearing is totally shot and running about 1.5mm off centre. This is why Porsche use the plastic impeller and there's fortunately no damage to the crankcase



With the inlet manifold removed we found an issue with the rubber joints, I think this has been causing some 'problems'



With the cam cover and cams removed on bank 2 there's no sign of why we have low compression. Everything looks nice and clean



Going deeper and removing the cylinder head reveals our issue. A nicely burnt exhaust valve



There's a lot of parts in the cylinder heads of these 4 cam engines







Having removed all the valves it's apparent this engine needs a valve job, look how rotten the seating faces are... Make sure you're using super unleaded if the manual calls for it. Min 98 Ron for the C4S



Cylinder head exhaust ports during and after cleaning





Having inspected all the cylinder bores I was pleased to see no scoring or cracks whatsoever. The bottom end will be left intact



Ims bearing cover removed for bearing inspection. This is the single row type and has minimal play, outer seal intact and no noise or grinding when spun



Thats all for now :)
 
Updates...

Parts have arrived so more progress.

Valves lapped to seats which is time consuming but was desperately needed as seen in the picture below of before and after



Quite pleased with how well the heads scrubbed up



New valve stem oil seals being fitted, then valves, shims, springs etc



One head done, one to go



To keep momentum up on other items needing immediate attention I stripped the brakes down and removed the discs for cleaning an inspection. The rears are fine but the fronts had a lip and some corrosion to the inner faces but were within spec so I had them skimmed and then cleaned out the drilled holes by running a drill bit through. After a quick clean and masking up the centres were repainted and these are good to go



Aside from the engine running on 3.5 cylinders on the test drive I noticed lots of creaking from the front suspension so new front coffin arms have been fitted.





You may have noticed I'm draining the front diff oil in the picture above.

That's it for now, tomorrow should see the new rads fitted and ims bearing removal tools fabricated.

Cheers



:thumb:
 
Nice work dude, good to see someone working on their car to that extent! :thumb:
 

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