Bits & pieces lead to disassembly, Vareocam and on..

Here is another engine VarioCam pad replacement job in conjunction with an AOS. On a 00 Dual Row IMS stock 996 after having the classic puff of white smoke out of the tail pipes and all the telltale signs of a bad AOS, I decided to of course replace the bad AOS which did end up having a torn diaphragm. While I was doing that maintenance task I also decided to drop the oil pan and do an oil change along with replacing the oil filter as well then inspect for any debris. To my surprise I found these bits and pieces of Black and Brown plastic. At which point I then decide to drop the motor and trans to have a better look at what else was going on. My local Indi mechanic confirmed my suspicions that I had a worn down pair of VarioCam pads and he suggested the black parts might be from broken chain rail. That perhaps it would be best to inspect further and see. So I figured what the heck why not just drop the motor and have a good look inside. The multiple black and brown pieces of plastic found at the bottom of the oil pan. My ZF tip-Trans and motor coming down after a few hours of prep work. Good thing too because the transmission mount is also looking rough and in dyer need of replacement prior to re-install among other desired projects. Up-close shot of the wear depth the chain has done onto the guide rails of the chain tensioner. Yes, tools P255 & P256 are installed. The chain chewed up quite a bit of material on the pads, this explains the bits of brown plastic I found in the oil pan. Now to figure out how to compress the tensioner plungers without Porsche tool #9634. As the search for the source of the black particles continues. Already looked at the old AOS and all parts inside were there so on to the next suspect item.

black peices could be from the IMS paddle. on the right in this pick. still in the bearing carrier case. you can see the black plastick 20150320_184612_zpsudz1qjfc.jpg or the oil scraper attached to the bearing case. you should be able to see that by taking off the sump plate.

Yep, those chain pads need to be done on pretty much every 996. Wear item. Done it on my previous one and will be doing them on this new one soon

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Even though it's a wear item, I've observed various rates of wear between different cars. Some have worn down quite a bit vs others at various mileages. It's hard to determine what kind of oil change intervals, climate, type of driving, etc. plays into this. It would be nice if we had some kind of inspection hole to take a peek from time to time.

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yeah....I'm going to make habit of dropping the pan every year to check out if I have bits or not.

AWDguy, thanks for the info and my indi suspected it was the Paddle plastic pad or the other black chain rail next to it. I checked what I could see of the oil scraper with the oil pan out and it's all complete. Going to open up the next bank this evening and see the wear. Alpine003 I wonder if the upgraded ones have the same or perhaps better durability then what looks like to be the original pads.

How hard are the pads to replace?

Very easy, you just need to drop the engine . Plus a bunch of special tools (that you can make your self) Might take a week or two. If the manifold bolts are seized on bank2 - prepare for passionate drilling

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"prepare for passionate drilling" This is what I say to the ladies in my life every once and a while. Sorry I know....TMI.

I made a tool for compressing the vario pads using a quick release skewer from a road bike wheel the threaded end fits into the threaded hole on the vario system which compresses the pads , you need to place a metal tube over the skewer with a washer on the end so it doesn't damage the vario tensioner, as you screw it in the tube and washer push against the vario tensioner and release pressure from the chain, it worked for me, be careful though as I've heard some are left handed thread, mine weren't and this method worked great for me!

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Actually only the 996's that have them. (1998-2001 non-turbo)

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Count on them being left-hand thread.

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Upgraded pads are far more durable, material looks like nylon. Here are some worn originals:

Thank you Byprovider, for the pictures of what the worn pads look like. NOZ1974, I tried the bike skewer trick but seems as though my VarioCams are reverse threaded since the motor is a 2000 996, so I'm awaiting a reverse thread cutting tool to redo the threads on the skewer rod. Which does actually fits in the tensioner assembly perfectly I also shifted focus to the IMSB while engine and trans are out. Bearing was the original Dual Row NSK with 100k on odometer and after removing the black seal there was no grease just engine oil in it with lots of play in all directions and minor abrasion on a few of the ball bearings.

^Great Catch! ^ Good luck with the rest!!!

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Indeed. Do you use a mag drain plug? Any debris in the oil?

Ahsai, there was no metal flakes in the filter all. I don't have a magnetic drain plug, but I did find bits and pieces of brown chain tensioner plastic and even more black plastic pieces in the oil pan after dropping it (see initial thread picture). Which is why I am tearing the motor apart to inspect further and see if it is the IMS chain paddle or what else is worn and broken.

Yeah my engine is an early 99 and the normal skewer worked for me but as I said later engines went left handed thread bummer !!

Plastic will be mainly vario pads brown plastic, black probably main chain Rails infront of timing chain tensioners

Bike tire quick release skewer with a few spacers to pick up slack and 5mm .8 pitch reverse thread (left handed) die cutter an ebay special for $5. Worked perfectly as suggested by Noz1974 instead of having to search and purchase that specialized Porsche tool. Compressing the VarioCam tensioners to have first hand look at the damage. Big difference of 100K worn VarioCam tensioner Pads 99610525300 versus new replacement Porsche part. Worn grove is actually much deeper on first pad than what is portrayed in the picture.

Very cool thread, thanks for posting. I'll probably do the same job this winter since I found lots of black plastic bits in the oil filter and in the oil pan in a recently acquired '99 C2. I've rechecked the oil filter about 500 miles after an oil change (included about 13 autox runs), and found only three tiny pieces of plastic (no bigger than 0.5mm). I plan to change the oil every 2K miles or 6 months and dissect the oil filter from now on as precautionary measure.

Device2 that's cool glad I could help, my original pads look the same it's as though the edges of the chains wear a groove , makes you wonder if the pads should have grooves built in for the chains to run in ?? I believe the replacement pads are a better less brittle material. Another tip, when you are re installing the cams/ vario assembly back on the head have the tool still in but just taking off a bit of tension to allow the cams to sit nicely in their bearings otherwise the tensioner pulls the cams too close together and they won't sit while you bolt up the vario and fit cam hold down tool on the other end. Might be worth doing the lifters while your in there??

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LOL. You can tell who does their own engine work by this very sentence here. Drop the engine? No big deal.

Lol, I do indeed all of my own work, but my sentece had some intentioned sarcasm in it. It's all fun though (with a bit of stress - keeps you awake at night) Btw, that bike tool is an awesome idea, I always used a pair of huge pliers and a metal wire to keep the VarioCam tensioner compressed. Once all it, clip the wire and remove

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FIFY

Engine removal really not that bad!! Glad my bike tool vario pads compressor is helping out, helI I might start selling a kit for like £100!!! Anyone interested ??

Check out my avatar , engine dropped!!

The disassembly continues. Removed the tensioners, the lifters and then the valve block assembly. As my search of the black plastic source goes on. I also noticed the long chain rails coming from the IMS shaft are slightly worn too. So looks like I will be replacing them too. Maybe this weekend I will have time to split the case to two and get a better visual of the black IMS chain rail in the front of the motor and the chain paddle. Which is my suspicion that the source of the black plastic is. Noz1974, looks like I might be doing the lifters too you're right since I' am already here. Also since I will more than likely now be doing a small rebuild or refresh of the old motor . Now I'm looking forward to it running a lot better with all worn stuff I'm finding and the things I'm replacing. Luckily no visual signs of cylinder head wall cracks

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Magnetic drain plug and neodymium magnets on the oil filter help for ferrous but for aluminum and plastic, dropping the pan is the best option. Check the w/p,idler pulley and alternator bearings at the same time? Dropping the pan and as others mentioned,replacing the exhaust manifold bolts =There is an intelligent alternative to using the same fasteners Use stainless steel studs instead. You will never fight seized/corroded/stripped threads again.Easy ,inexpensive job that I have detailed in the past.All hardware available on EBay.

Boy if there ever was an ad for American small block V8s this thread is it. The 996 engine must have been old Doc Porsche's gift to the parts and service department. Does anyone else feel that the concept of finding bits of plastic in your oil pan is...wrong? I feel as if I'm reading about a Chinese motor, not a German one. How does this square with all the high mileage motors posted here?

I was able to get a decent visual on the IMS chain paddle and the IMS black chain rail along the RMS and down below it. But looks like my lower chain rail from Cylinder 1-3 chain had a good chunk dug out and some damage from whatever foreign object the chain swallowed up and ran through. Also the VareoCam tensioner pads on Cylinder 1-3 are even more chewed up than the ones from Cylinder 4-6. The ring was folded in half and the pads are very eaten up. Looks like I will be placing that and a few more items on order with WareHouse33. Gonna get new rail pads, seals and some new lifters . Schnell Gelb, thanks for the tips and yes I will check some of those items. I've actually already replaced the Idler Pulley bearing and the other two. I also plan on also going with lower temp thermostat and replacing the IMSB & RMS. Johnireland, I have to agree with you in contrast to the other 3 German vehicles that I have owned, two of them being luxury brand ones mind you this 996 Motor for sure did ensure job security for the parts and service department at Porsche. Yeah I too feel as though the 996 Motor has it's flaws and too many frequently need to service items but it is still fun to tinker with. Also I think it's safe to assume that the previous owner did not take this car in for regular service cycles or have the mechanical aptitude to pay much attention to what was going on with the vehicle.

If that o ring was folded over, the oil feed to the pads was probably not as good as it should have been, I would say everyone with over 80k on their motor has vario pads looking the same as yours, I've stripped two engines my original with 102k and the replacement I bought with 82k and both had knackered vario pads, if you are showing increasing can deviation values you can bet it's this , it's a wear item like anything else, we all go on about ims Rms AOS and the rest we need to add VCP ( vario chain pads) . The main chain rails do get a bit of wear also but not like these fortunately!!

I talked to the indi mechanic yesterday about my plan to replace my lifters and he said that I needed to be careful about uneven wear on the cams. Anyone experienced this when changing all the lifters? Would it be a bad idea or a good thing to do since the motor is out. The car does have 100K miles and I was wondering if anyone has done it and had adverse effects? I do plan on changing all 24 and not one or two. Which is what I think he was referring to causing the damage, doing one or two I recall having read somewhere that doing individual ones it is something to wary of and they could cause uneven wear.

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Thank you for your business, if you have any questions just let me know. -Jason

Well here is the outcome of the bits and pieces. Looks like the IMS chain paddle did take on some damage too. Here is the new Black IMS Chain pad versus the old original pad from Stuttgart. Go figure removed the original factory installed Cam tensioner pads with Manufacture date May 1999 (05/99) as seen in the part .

Other than dropping the oil pan and hunting for plastic, is there any way to inspect the condition of the pads and guides?

Interesting to find this thread. I actually am finishing up the rebuild of my engine and the pads were mostly worn. THe pad that was most worn out was the IMS Chain pad. I bought a new one from the porsche dealership for around 25 dollars. It was the only pad that didnt come with the Vertexauto.com 3.4L Rebuild kit I bought. All other pads came in the kit.

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Careful with that word, "rebuild" around here. Some would consider that a refresh instead.

@Device2 - I'm catching up , for the IMS paddle, case spliting is required or not? Thanks

Youri Ko, I will have to say that due to the room required to remove the IMS chain paddle in order to change the black plastic the answer would be "Yes!" To the Case splitting or at least removal of one half is necessary. Sad part is that it took no more than 5 minutes to remove the circlip, the washer and the paddle - then replace the $20 black plastic part 99610519500 and re-install. So now it also looks like it will cost about 25X that amount to purchase new seals, O-rings, cylinder head bolts and so on to reassemble and close everything up .

Thanks Device2. I refreshed my engine last month, VarioPads, rms, ims and whole bunch of seals, did not touch any of the big paddles. Oh well, more and more stuff to watch out for on these engines as they age. In a few years, IMS won't be the big word but plastic paddles will be and people will start to run away from these cars scared