[Harvey]

968ers,



I ordered the cam chain, pads, seals, etc. for the 968. However, when I took the cam cover off, it looks almost pristine inside. No maintenance history on this car but the primary previous driver traded it in on a Bently, so one might assume she kept it up and at some point the chain and pads were replaced. No real way of knowing I guess. HOWEVER...



1) The bolt holding down the cam chain oil tube was a hex head...not a cheese head...is this normal? (I'm looking for a clue that someone's been in there). All cheesehead bolts are good shape. None buggered up.



2) Cam teeth and lobs are virtually perfect shape.



3) I spent an hour with good lights and Derek Holliday's cam chain check list and all looks perfect except for some VERY MINOR wear on the leading edge of the top tensioning pad (the edge closest to the fender), the rest of the pad hardly shows wear and the wear that does show is minimal at best. The car has 70k miles on it. I just put 3,000 miles on it myself.



Therefore, I'm leaning towards just leaving it as is and checking it every 5,000 miles or so. On the other hand, changing out everything doesn't look like a difficult job but I have a few important questions before I would finally decide:



A) How in the devil does one remove the cams with all the tension on the cam chain? I'd heard of a compression tool or something. How much does it cost? Who sells it? Is it required? There's a lot of pressure there.



<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> Also, when one takes the bolt out of the end of the exhaust cam, does the cam belt toothed pully come loose too? I don't want to lose my cam timing. Someone had said that if I pick up 3 small bolts (5mm x 16mm or so) after removing the distributor cap, then screw these bolts into the holes that the distributor cap bolts went into, and tighten them down that the the cam drive gear would stay in place while I remove the cams. Am I correct in my understanding?



C) Once the cam chain tension is loosened and the cam drive gear secured, and the cam tie downs removed, and the cam end bolt removed, will the cams just pull out without any special tricks?



D) On reinstall, do the lifters pose any caution/challenge?



Just being cautious on my first time in there. If you've done this before, your response would be most welcomed.



Thanks,



Harvey

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[Greimann]

Having never been into the motor that deep, I can't comment other than suggest that you get ahold of the service manual. It spells out some of the techniques about removing and installing the cams.



You can download it from the DIY section on this forum (243 MB!)

http://www.968forums.com/index.php?showtopic=366



If everything looks good, I don't think I would touch it either.

Here is an archival picture from my inspection. It may help with your bolt question:

   

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[Eric_K]

I think Raj answered most of your questions on 968.net. If everything looks good I would just put it back together and consider youself lucky. If you really want to change the chain and pads it is not that bad of a job though.



1) The j tube bolt for the variocam is a banjo bolt so if it not right you will know it - because the tensioner wouldn't work.



a) The 2 cams, tensioner and chain come out as one group. No special tricks - they will lift right out once everything is unbolted. Remember to work your way around slowly loosening each bolt a little at a time.



Yes, placing the three bolts on the cam pulley once the dist rotor is off will lock it in relation to the exhaust cam. This will ensure the timing is the same as when you took it off.



d) There's no reason to touch the lifters if you are just changing the chain and pads. If your cams are in good condition then most likely the lifters are too.



There are some special tools listed in the manual to keep the tensioner compressed and to seat the cams. I didn't use these, but that said, it is always best to use the right tools.



This is what I did - proceed at your own risk. On reinstall I compressed the tensioner by hand and slid it inside the chain and between the cams. I then placed the whole assembly back on the head. Use your third hand or an assistant to push down on the top of the chain to compress the top pad. This relieves any tension on the chain so that the cams can be postioned properly. Seat the cam in position by hand. Reinstall the bearing caps in the same postion they came from and slowly and evenly tighten down each cap. Make triple sure the cam is going in evenly. I worked form the inside cap to the outside cap and tightened it down in 5-6 passes.



Eric

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[Harvey]

Thanks guys,



That's the to-the-point info I was needing. I will take a closer look at the 968 manuals but my experience with the 928 manual is that it leaves a lot to be desired and assumes a lot of experience. And it's hard to find the info you want. Direct information from someone who has been there and done it is very important, I've found, and saves a lot of frustration. Someday, I hope to be able to repay to the list when other newbies come on.



Losing a belt or a chain is not worth the risk so one has to be extra cautious. I almost bought a black 968 is Seattle whose engine had been granaded....but there were other things wrong with it too...all indicative of lax care.



Again, much, much thanks.



Harvey

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[Eric_K]

Here is a link to a 968er who documented the job.



Cam removal, Variocam Pad and chain replacement



Eric

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[NeedPorscheSpeed]

Harvey, you are are right in saying that the Porsche Manuals assume a lot of experience. (I suppose if they did not, they manuals would have three times the amount of pages as they do currently.) Because they assume so much experience, I also prize the experiences of others. That is a perfect lead-in to thank Eric for the link to the DIY write-up that he posted. Eric, thanks a lot; I had never seen this one before. I currently have my camshafts removed and it is always great to be armed with the experiences of others. <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[Harvey]

Thanks, Eric. Great belt change article! Now...patience until my parts order arrives. The crank lock and spanner tool arrived today from Paragon ($150+ bucks for the two...ouch!) They sure ship fast.



I'm still looking for part 2 of the belt change article. I didn't see a link to it from M. Hammond's web page. Maybe he's still out having a coffee.



Harvey

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[Harvey]

I found it by playing with the URLs. Great article for the DIY people.



Harvey



[quote name='Harvey' date='Apr 16 2005, 01:38 PM']Thanks, Eric. Great belt change article!  Now...patience until my parts order arrives. The crank lock and spanner tool arrived today from Paragon ($150+ bucks for the two...ouch!) They sure ship fast.



I'm still looking for part 2 of the belt change article. I didn't see a link to it from M. Hammond's web page. Maybe he's still out having a coffee.



Harvey

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[NeedPorscheSpeed]

[quote name='Harvey' date='Apr 16 2005, 02:48 PM']I found it by playing with the URLs.  Great article for the DIY people.

Harvey

[right][post="3328"]<{POST_SNAPBACK}>[/post][/right][/quote]



It looks as if he were not still out for coffee after all, Harvey. <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />



For anyone else out there who might have trouble finding part two of the DIY article, just click on the right arrow as pictured here:

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[Eric_K]

Sorry, the address for the main page of Mike's site is:

http://freespace.virgin.net/mrmike.hammond/index.htm



Eric

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