[xrad]

as above. ...the v8 pad/tensioner(s) are different too.

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[earossi]

I forgot to mention one other potential pitfall on disassembly and reassembly of the cams. When removing the cam bearing caps, take the safe route and back each bolt out a little at a time to prevent putting a bind on the cams if they decide to "pop" out of the bottom bearing. When reassembling, you may find that it is hard to get the cams to remain seated in the lower bearing shells, which means that you will draw the cams down into their final position by tightening down the bolts on the bearing caps. You should be very careful here and tighten (using a cross torquing pattern) the bearing cap bolts very slowly and evenly so that there is no chance that you will distort the camshafts. Pete, as RS Barn provided that little jewel of wisdom, and I can see how you could get easilly into trouble if you decide to fully torque down the first bearing cap with none of the others installed. Porsche wants you to use a jig to hold the cams in place, but I found that I could get away without the setup simply by "evenly" and slowly tightening the bearing cap bolts.

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[xrad]

took cam cover off today. WOW..everything was spotless on the inside. Only tiny bit of grudge in the cam cap bolts. Tensioner pads with about 1/2mm wear grooves. chain and sprokets look sharp. cam lobes very clean without pitting.



Had a little problem with a few exhaust side cover bolts. they decided to twist a little before breaking loose and giving me an MI! Going to glass bead blast the PO's white paint off the cam cover and polish it up tomorrow. Ordered a new set of top end bolts from Sunset. All cam cap bolts, two shorts(20$ each), and all the longs totalled 140$ plus shipping. Cam cap bolts a deal at 1.50$ each!

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[xrad]

some pics to go with the above:





look closely and you can see the wear grooves on the top pad. I spoke with a Porsche mechanic today and he said there is no pad change interval(we knew this), but he suggests preventive maintenance of 50-60 thou which goes with the timing belt.

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[RPM]

Looks good. How many miles? My old S2's pads were far more worn than that when I replaced them at 112k.

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[midblu]

xrad- your top pad looks similar to what mine looked like when I had them changed out. I have a feeling that your lower pad is going to be twice as deeply grooved with substantial pitting as the lower pads tend to deteriorate quicker. Glad you are changing yours out! Post pics of the old pads when you can.



Ron

94 coupe/6 speed

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[xrad]

110,000 miles....but someone was under here before me to change out some parts. belts look too new. Chain and cam teeth look fresh. I am delayed a while as some of the gaskets were not in my 'complete' kit...such as two crush washers for the vario oil line banjo, vario paper gasket and O-ring. Also needed some new bolts as stated above.



I glass bead blasted the crummy white paint off the cam cover today and will drop the cam and wire cover off for polishing at McNichols on telegraph, redford MI(maybe I will do the intake, too......)



http://www.mcnicholsanodizing.com/

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[xrad]

look at these babies!! 6 hours of polishing by a pro....just need to wax off my fingerprints! Next is the intake...maybe the block....maybe....

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[rxter]

Holy Smokes! Those look fantastic. How much did that set you back, if you don't mind? We discussed hand polishing and the probability that I will do that is low given the labor involved.



Pads - when you check the bottom pad can you try to get a pic like you did with the upper? That is really helpful to see it prior to going in for the less brave amongst us. I am curious to see if Ron's prediction is correct. Since it is so much more difficult to get a look at the lower pad I wonder how many times they just get skipped by the mech.

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[rob76turbo]

xrad, those look great!! What was used to get that surface polish?

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[xrad]

Thanks guys! These needed about 6 hours polishing with 400 and > sandpaper, followed by different grades of flexable abraxive pads and wheels, and hours of die grinder with polishing tips, followed by fine buffing on a big wheel, followed by hand polishing with something like chromex, followed by carnuba wax as a surface antioxidant.



cost: 480$ ( his guys were able to remove all but three deep casting pits, and these are minute and hidden. also, no damage to the mating surfaces during the polishing process: ie: no one dropped it!)



ask for mike at McNichols...website listed above. If you don't have someone in you area who does this work, mail them to mike and I can check the work before he ships them back to you. he does not take credit cards so you will have to wait for a check to clear. this is not a fast process as he has much work to do. expect to be without your ride for several weeks minimum.



Another pic: looks awsome in person with the new zinc chromated washers and screws.

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[PorscheDude]

Awesome! Now I am motivated again to finish off my extra cam cover.



I have an extra intake if you want to send it off.

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[xrad]

yeah, i would love to trade...just don't have the time to pull it off right now. Maybe in October.THANKS

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[earossi]

[quote name='xrad' post='56570' date='Jul 21 2008, 06:08 PM']Does anyone know absolutely if the upper and lower chain tensioner pads are exactly the same?



What do you guys recommend for the best timing chain? (endless links like Iwis? or something heavy duty?)[/quote]





As pointed out elsewhere, the top and bottom pads, on the 968, are identical. On chains, I would recommend going OEM. Get you parts through Sunset Porsche and the price on the chain, if I remember correctly, is about $50. The chain does not have a removable link which is why you must remove the cams to replace the chain.



If you decide to do the job yourself, allow about 12 hours the first time around. Having done the job the first time in about that number of hours, I now believe that I could do it in less than half that again.



The are several minor items when tearing the system down. Like ways to remove the cam bearing cap bolts which strip easily. There is also an alignment gauge you will have to make to orient the rotation of the cams on reassembly. And, lastly, I highly highly recommend that you get the varicam tensioner lock which allow the tensioner to be held compressed while installing the cams. YOu'll also need the pin that allows you to lock the timing belt tensioner in the compressed state for reassembly.



The nice thing about those tools is that they are cheap and are available from Sunset for about $35 for both retainers. I fashioned my own tools since they were back ordered at Sunset, but have since gotten them from Sunset.



Also, there are a number of excellent DIY posts both on this web site as well as on the Rennlist website.



Let me know how it goes.



Ernie

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[ds968]

[quote name='earossi' post='58328' date='Aug 25 2008, 02:53 AM']The chain does not have a removable link which is why you must remove the cams to replace the chain.[/quote]



I was at my mechanic the other day and talked to him about this - he said there are crimping tools for timing chains

( he actually has one in the shop and has used it for this purpose on a few MBZs chains ) that can be used to do the same job on the cam chain, so the variocam service could be done without need to remove the cams. My first thought was: YIKES ! Are you f'n kidding me ? No one in his right mind would take a chance with a cut and crimped chain but he went on to explain the way this works and how it binds together is essentially the same as the chain links assembly by the manufacturer so there is no greater weakness in that spot as opposed to any other links / joints.. I guess that could be the case, but I still have an uneasy feeling about it <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" /> though not sure why.. everything this guy has done on my porsches or mbzs in the last twenty years has been flawless, and in many cases has repaired and rebuilt various parts using machine shop skills and tools where the "safe" thing to do would have been to just order the new OEM part. Thus no reason to question what he is saying, but he did admit that he has not worked on a 968 variocam so without looking into the exact set up, the chain replacement via crimping method is only possible in theory at this point.



But even if it is, can the tensioner pads be replaced without removal of the cams ?

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[xrad]

I think I would rather have the machine crimped chain. Very uniform. The febi chain I bought also has solid tube roller bearings (unlike stock, which has rolled tube bearings and a seam)

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[earossi]

[quote name='xrad' post='58656' date='Aug 29 2008, 07:56 PM']I think I would rather have the machine crimped chain. Very uniform. The febi chain I bought also has solid tube roller bearings (unlike stock, which has rolled tube bearings and a seam)[/quote]





[quote name='xrad' post='58656' date='Aug 29 2008, 07:56 PM']I think I would rather have the machine crimped chain. Very uniform. The febi chain I bought also has solid tube roller bearings (unlike stock, which has rolled tube bearings and a seam)[/quote]



So, now that you have the car back together, can you venture a guess to how many man-hours the job took you, not counting the down time waiting for parts? Just curious.

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[xrad]

a total of two hours (covers on and off with new retainers)....... so fast because I did not get to do the timing chain yet.



will do job at end of october due to time restraints.

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[FRporscheman]

$35 for the tensioner clamping tool from Sunset? Give me a break. I made my own tool out of heavy gauge steel rod by just bending it in the right places with pliers. And yes it works, I tried it out! I also made my own tool to compress the belt tensioner, and that one works too <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />.



If anyone in the bay area needs help with the variocam service, let me know, I've done it 3-4 times and I've gotten really good at it. Last time it only took me 6 hours to change the pads and chain for a friend while he watched.

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[FRporscheman]

See attached image, upper and lower pads from a male-owned 6-speed coupe @ 105k. I'll take better pics later.

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