996 IMS, timing chain guide, transmission pinion bearing and misc items DIY project
02-11-2011, 09:14 PM
#47
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Sorry, don't have the part numbers just called Sunset Porsche and told Jeff what I wanted to do and he knew all the parts that I needed. I didn't replace the guide tube, but I did replace the throwout bearing.
02-12-2011, 12:42 AM
#48
Nordschleife Master
Jeff is the man when it comes to getting parts. He'll tell you what you need and don't need. I normally give him a list and then he replies noting any discrepancies or newer updates.
02-14-2011, 11:33 AM
#51
Nordschleife Master
Jon,
The pitting on my spider gears were still minor so I left it in, the pitting condition can vary from car to car. Not too difficult to replace.
I did upgrade the clutch fork and the pivot point, made a huge difference on how smooth the transmission shifted and the pedal force. Prior my clutch pedal required a lot of force.
The lifters looked fine, but I know there were probably a hand full of them that could be replaced as I do hear a little lifter noise at idle but goes away the second I give a little gas. I decided to leave them as they were, again no big deal if I had to go back and replace them.
The biggest surprise to me was replacing the CAM chain plastic guides, as now I can hear and feel the variocam working. I didn't replace any spark plug or coils so I know my power increase the engine tone change had to come from replacing the CAM chain guides. Hard to imagine it would make that much difference.
The pitting on my spider gears were still minor so I left it in, the pitting condition can vary from car to car. Not too difficult to replace.
I did upgrade the clutch fork and the pivot point, made a huge difference on how smooth the transmission shifted and the pedal force. Prior my clutch pedal required a lot of force.
The lifters looked fine, but I know there were probably a hand full of them that could be replaced as I do hear a little lifter noise at idle but goes away the second I give a little gas. I decided to leave them as they were, again no big deal if I had to go back and replace them.
The biggest surprise to me was replacing the CAM chain plastic guides, as now I can hear and feel the variocam working. I didn't replace any spark plug or coils so I know my power increase the engine tone change had to come from replacing the CAM chain guides. Hard to imagine it would make that much difference.
Robin,
Are you going to have to drop the engine again to get to the lifters? Are they a replace only or can you clean them out and drop them back in?
02-14-2011, 11:46 AM
#52
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It is possible to replace the lifters with the engine in, but it would be hard to line up the cam sprocket back to where it was just because it would be hard to see when the engine is in the car.
They are not serviceable parts, just need to replace them when they go bad.
03-12-2011, 05:18 PM
#53
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996 my1999
Robin,
I own a 1999 996 C2.
It has just about 106000 miles on it.
The check engine light is ON, checked it and it said camshaft sensor, changed it and now it seems there is a difference in the timming angles?? Have you heard about this, I asked if I need to change the timming chains, they said no they are really strong chains but there is probably something wrong with the computer cause it should adjust the angle automatically so I need to reprogram the computer and get it fixed?? Hear about this??
I would really apreciate your knowledge about this, I'm in Bolivia South America no porsche dealers or autorized mechanics, I just imported this car for the US for my personal use.
thanks
Sergio
I own a 1999 996 C2.
It has just about 106000 miles on it.
The check engine light is ON, checked it and it said camshaft sensor, changed it and now it seems there is a difference in the timming angles?? Have you heard about this, I asked if I need to change the timming chains, they said no they are really strong chains but there is probably something wrong with the computer cause it should adjust the angle automatically so I need to reprogram the computer and get it fixed?? Hear about this??
I would really apreciate your knowledge about this, I'm in Bolivia South America no porsche dealers or autorized mechanics, I just imported this car for the US for my personal use.
thanks
Sergio
03-12-2011, 08:11 PM
#54
Rennlist
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What exactly is the code number?
If it is the cam position sensor then there is only 3 possible reasons why you are getting this CEL:
(1). Timing is off
(2). Sensor bad
(3)l Wiring bad
If it is the cam position sensor then there is only 3 possible reasons why you are getting this CEL:
(1). Timing is off
(2). Sensor bad
(3)l Wiring bad
07-24-2011, 12:08 PM
#55
Drifting
That's amazing write-up and pix to document the process.
A few questions please if you don't mind as I'm looking at getting into an earlier (2000 MY) 6-speed 996 with high (100k miles) transmission mileage but a low (40K miles) pre-owned engine supposedly due to mis-shift induced valve train damage on the original engine. Experience-wise I have done a few timing belt changes on DOHC engines, have a compressor and impact wrench, and have worked on cars hobbist-style for 20 years.
1. What brand/model scissor lift did you use? Looked like you had to drive the car up on a few planks of wood to gain sufficient under-car clearance?
2. Will the A/C lines have to be disconnected from the A/C compressor when you mentioned "removal of A/C compresser"?
3. Doesn't sound like the various timing, intake/exhaust, IMS chains were replaced in your advanture, any particular reason they were bypassed when you are already this deep in? Same question with the IMS, i.e. replace with the full IMS shaft from LN rather than just the bearing kits?
4. I'm not likely to tackle the transmission bearing myself, and will use someone local since I just do not have the right equipment, roughly how much does it weigh? (a couple of hundred pounds?)
I guess the only unknown now is the possible cyliner crack that I've read about, which I understand is irrepairable........
Thanks in advance for the inputs.
A few questions please if you don't mind as I'm looking at getting into an earlier (2000 MY) 6-speed 996 with high (100k miles) transmission mileage but a low (40K miles) pre-owned engine supposedly due to mis-shift induced valve train damage on the original engine. Experience-wise I have done a few timing belt changes on DOHC engines, have a compressor and impact wrench, and have worked on cars hobbist-style for 20 years.
1. What brand/model scissor lift did you use? Looked like you had to drive the car up on a few planks of wood to gain sufficient under-car clearance?
2. Will the A/C lines have to be disconnected from the A/C compressor when you mentioned "removal of A/C compresser"?
3. Doesn't sound like the various timing, intake/exhaust, IMS chains were replaced in your advanture, any particular reason they were bypassed when you are already this deep in? Same question with the IMS, i.e. replace with the full IMS shaft from LN rather than just the bearing kits?
4. I'm not likely to tackle the transmission bearing myself, and will use someone local since I just do not have the right equipment, roughly how much does it weigh? (a couple of hundred pounds?)
I guess the only unknown now is the possible cyliner crack that I've read about, which I understand is irrepairable........
Thanks in advance for the inputs.
07-24-2011, 03:40 PM
#56
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I bought an Greg Smith Equipment scissor lift, you will need to use some wood to clear the height so you can drive a car on there. Normally I park a car on there when the lift is not in use.
The A/C line will not need to be disconnected just like the 993. But removing the angled A/C compressor bolt can be a little tricky. Easier if you remove the throttle body and guide your socket into the right spot.
Because replacing the chain would require the entire engine to be taken apart, which was not necessary in the 100k miles refresh. So I only replaced the various plastic timing chain guide ramps. The IMS bearing kit sufficient enough not need to replace the IMS shaft.
Never weighted the transmission, but I would guess maybe 100lb? Engine probably around 400lb.
6 month after the refresh here are some update:
We opted to leave the pinion bearing seal out during the the transmission rebuilt, the transmission still shifts perfectly with no ill noise. However I noticed there is a built up pressure inside the transmission, I can hear a hissing sound when I remove the filler plug. The pressure has not caused any blown seal or leaks yet, but keeping my eyes on this. Not sure what would cause the transmission not to vent properly, thinking maybe the thick grease from the pinion bearing maybe blocking the vent hole on top?
As for performance, after replace the timing chain ramps I can again hear the engine pitch change when the variocam kicks in and a definitely SOP power difference. My gas mileage increased from 21 - 23 mixed highway / city driving. So far I am very happy with the refresh.
Thanks
The A/C line will not need to be disconnected just like the 993. But removing the angled A/C compressor bolt can be a little tricky. Easier if you remove the throttle body and guide your socket into the right spot.
Because replacing the chain would require the entire engine to be taken apart, which was not necessary in the 100k miles refresh. So I only replaced the various plastic timing chain guide ramps. The IMS bearing kit sufficient enough not need to replace the IMS shaft.
Never weighted the transmission, but I would guess maybe 100lb? Engine probably around 400lb.
6 month after the refresh here are some update:
We opted to leave the pinion bearing seal out during the the transmission rebuilt, the transmission still shifts perfectly with no ill noise. However I noticed there is a built up pressure inside the transmission, I can hear a hissing sound when I remove the filler plug. The pressure has not caused any blown seal or leaks yet, but keeping my eyes on this. Not sure what would cause the transmission not to vent properly, thinking maybe the thick grease from the pinion bearing maybe blocking the vent hole on top?
As for performance, after replace the timing chain ramps I can again hear the engine pitch change when the variocam kicks in and a definitely SOP power difference. My gas mileage increased from 21 - 23 mixed highway / city driving. So far I am very happy with the refresh.
Thanks
07-24-2011, 04:07 PM
#57
Drifting
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I just had this done to my 996 recently and the shop indicated they had issues with pressing the gears off too.
The hardest part was to press the gears and bearing off, which required a very high tonnage press. In addition you will need to fabricate plates of various size to grab on to each of the gears while they are pressed out.
You should contact Chris Walrod for details, as he did all the pressing and fitting.
Thanks
You should contact Chris Walrod for details, as he did all the pressing and fitting.
Thanks
07-25-2011, 05:15 PM
#59
Racer
Great thread, I did not realize the 996s were easy to work on. That's one of the reasons I've been reluctant to move on from my '88 Carrera. I completely rebuilt the engine down to the crank about a year ago but crappy ac is starting to get really old, even with improvements it's only "decent". Met a guy in my office parking garage who went to a 996 from 14 years with a Carrera and never looked back.
01-17-2012, 02:42 PM
#60
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Sorry for reviving this thread, but there is so much great stuff in here that I find it worth to be rehashed.
After dropping the engine to address several issues (noisy valve lifters, clutch slipping and 2nd gear grinding), I have been in contact with Chris on the tranny part. He has been very helpful and the gear stacks are in a local shop now to press everything off.
Conclusions sofar:
The redline shockproof gear oil has done a great job. Pinion bearing looks like new, spider gears are all in great shape.
I guess my tranny problem (2nd gear grinding) is due to bad synchros or the 1st/2nd gear guide sleeve. Will find out once I can have a good look at the pressed off parts.
I have the timing tools on order and as soon as they are in we'll tackle the valve lifters and maybe the variocam pads. We'll see..
JP
After dropping the engine to address several issues (noisy valve lifters, clutch slipping and 2nd gear grinding), I have been in contact with Chris on the tranny part. He has been very helpful and the gear stacks are in a local shop now to press everything off.
Conclusions sofar:
The redline shockproof gear oil has done a great job. Pinion bearing looks like new, spider gears are all in great shape.
I guess my tranny problem (2nd gear grinding) is due to bad synchros or the 1st/2nd gear guide sleeve. Will find out once I can have a good look at the pressed off parts.
I have the timing tools on order and as soon as they are in we'll tackle the valve lifters and maybe the variocam pads. We'll see..
JP