[Scott Collins]

   



Here is my new approach to remove front engine seals. About 5 min for each seal. <img src="/forum/images/smilies/968/rock.gif" class="smilie" alt="" />



   



Here is the old approach. Days per seal. <img src="/forum/images/smilies/968/whine.gif" class="smilie" alt="" />



Here is what the timing belt looked like, with 4 years and 32k miles, driven just about every day in all seasons, here in Central NJ.

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[Cloud9...68]

Amazing the difference the right tool/technique can make, isn't it? Are you referring to the front balance shaft seals? Were yours leaking? Mine weren't when I did my belts a little over three years ago, but they were practically the only seals on the entire car that weren't. I replaced them anyway; I threaded a drywall screw into them as far as I could, then grabbed the screw with a pair of vice grips and yanked until I nearly pulled the engine off its mounts and out of the car! Your new method looks much better <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[Scott Collins]

I've used that technique, but I kept getting little chunks of the gasket and metal shards all over everything in the process, so I figured I would end that method. Believe me, that little prybar, from Advance Auto, which came in a set of three, is much better.



My upper balance shaft seal was the only one leaking. The lower one is supposed to go first, since it is closest to the heat source of the exhaust header. Go figure....

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[Scott Collins]

   



Here's a great way to tap in the balance shaft seals, particularly the lower seal - use the oil pump drive gear sleeve - the one you just removed are were going to throw out. It fits perfectly and is short, giving you some space to get a hammer on it sideways for some tapping.

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[Scott Collins]

Update: almost done! Check out the pics below!



   

The head is back from the machine shop - clean, with new valve guides.



   

Torquing the head in three stages - using torque angle guide for 2nd and 3rd stages.



   

Ready to "pull the pin" on the timing belt hydraulic tensioner





   

Timing the cams with dial indicators



   

Valve cover installed. Cleaned with glass beading and treated with a clear coat finish.

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[Cloud9...68]

Nice job! Your valve cover looks gorgeous, and it really dresses up the engine.



Did your run into any pitfalls with the job? Was timing the cams difficult? Did you disassemble the variocam assembly, and replace its o-rings, or did you leave it all intact? Thanks; hopefully it will fire right up and purr like a kitten.

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[Scott Collins]

All o-rings and gaskets replaced, for everything - variocam, oil filter housing and oil cooler housing, the whole works. No point in getting that far into it and not doing those things. Got the coolant hose kit from Paragon and also replaced a number of hoses, including the really hard to get to ones at the rear of the engine.



Plenty of little "time robbers", like looking for a balance shaft bolt for 30 min that I had placed in a tool drawer with the wrenches that were also in my hand, having a really tight balance shaft race that wouldn't go on all the way past the woodruff key slot, which involved me removing that entire front cover to get to that. That is the lower shaft cover, which supports the p/s pump, which delayed the installation of the water pump because that would have been in the way. That was at least a 3 hr delay. Balance shaft seals that don't want to tap in straight.



Every time I do a job like this, one very involved, I come away with even more respect for guys who do this for a living.

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[Lear35A]

Scott, your picture of the cam timing got my attention. I understand that the indicator on the #1 inlet valve is supposed to be sitting on the top of the lifter. I see yours on the cam lobe itself. Also I don't see you pressurizing the variocam. What procedure did you use?

I've attached a picture of my setup, but you can't really see the tip of the indicator. It's a 45 degree tip. It's very difficult to line it up so that the cam doesn't hit the indicator tip as the cam is rotated.

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[Scott Collins]

Lear35A,



That pic is just a photo of stuff being put in place, not intended to be used as a resource per se. Just so the members can get the idea of what happens. I'm not trying to make it a DIY, with exact instructions. The intake dial indicator is right where it is supposed to be, but the pic has a shadow. Your photos are more of what I would want to see if I wanted to review a DIY - much more accurate. My pics are just the "Cliff's Notes" of the project.



Cloud,



I would say that the timing of the cams is something for a highly skilled technician with experience and the correct, very hard to get collections of tools. Timing my '87 944 was a walk in the park compared to this engine! The workshop manual will give you an idea. And the marks on the flywheel and cam gear can only be used to approximate the correct positions. Only with the dial indicators can you really find <acronym title='top dead center'>TDC</acronym>, exactly, and the proper opening of the intake cam in relation to <acronym title='top dead center'>TDC</acronym> of piston #1.



-Scott

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[Lear35A]

This is just my personal opinion and experience on the matter. YRMVs



Many or even most would want to turn this over to an experienced technician. However, even though cam timing does take some practice and it's a bit of a PITA, it's not rocket science. The tools aren't hard to get or expensive either (and one can never have enough tools <img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" /> ). The technique is covered pretty well in the manual, and there are numerous write ups that amplify and clarify the procedure.



If one has some mechanical ability and the inclination to do-it-yourself, go for it.

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[Cloud9...68]

I'm going to give the cam timing a shot. Between the experience of the folks on this site who have done it, and living down the street from a guy who recently rebuilt the engine from his 964, I think I have enough resources to make a go of it. Plus, having the engine out will at least give me all the access I'd ever need to get a clean, unobstructed view of everything.

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[kwikt]

That would be great Cloud9. I timed the cams on my 911 multiple times but never on the 968. Curious to see if there are any tricks or tips because it does sound a little complicated especially with the pressurized tensioner.

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[RS Barn]

Lear,

Those are my tools and I'm timing the cams. There are many little quirks to getting cam timing correct. The factory manual leaves many questions on how to do. They atually show wrong cam location in picture .Didn't I guide you through procedure? I know we talked alot

This isn't for back yard mechanics and can easily be a disaster (Cloud)

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[Lear35A]

Pete, you gave me a lot of great help on the cam timing. It was invaluable! It took awhile, but I am comfortable doing this procedure now. There is some satisfaction when you finally figure it out. To do this one needs: the right tools, no time pressure and patience. I definitely had a learning curve, but after the assembly my engine started immediately. It runs smooth as silk to the redline and feels very strong.



Unfortunately many of us live nowhere near a qualified technician to do this for us. We are forced to be more self reliant.

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[Cloud9...68]

Lear makes a good point that many of us, who don't live near someone with expertise and experience on this, are on our own. I know some people who have done it have put together partial descriptions on how to do it, but I'm not aware of a thorough, step-by-step guide. Does such a thing exist? It sure would be helpful if it did.



One question - is timing the 968's cams more or less difficult than timing the cams on a comparable-vintage 911, such as a 964? I ask because I know someone who rebuilt his 964 engine, so of course had to time the cams, and he said that while the description was confusing, it wasn't beyond his ability to comprehend and get it right in the end.

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[Scott Collins]

ALL DONE!



Special thanks to Pete Fitzpatrick of RS Barn. Fortunately for me, Pete is within 45 min of my location. Pete provided technical support and supplied a number of the special tools needed for this project, such as cam blocks, which are important for removing and installing the cams without causing damage.



   



Pete also assisted on site and checked at critical stages in the project to verify that I was on target. He noticed that a few things still needed to be done and made sure we did not attempt startup until every last detail was validated. His help and experience was invaluable.



I have even more respect for Porsche and for professional or amateur technicians who have the ability and experience to do this sort of work.





Will post pics soon.



-Scott

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[DaveN]

Funny that little thing called "experience" can do. My friend and 30 year P mechanic just rebuilt my motor in prep for the SC. I was down the day we timed the cams and saw no dial indicators. There was a little piece of paper cut to the shape of 2 cam lobes from the a factory manual template. <acronym title='top dead center'>TDC</acronym>, place the template over the lobes until they fit and done! The only issue we had was that one of the timing stamping marks on a belt gear (can't remember which one) was off my 1/2 tooth so we were confused for a bit as to whether it was the left or right tooth that was the correct one. Of course the little paper template didn't line up so we new there was a problem.

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[tamathumper]

How awesome is that! <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[RS Barn]

Dave

The template is only for checking to see if the cam chain is located properly on the sprockets. When they are correct and you have #1 Piston at <acronym title='top dead center'>TDC</acronym> firing the lobes will be in correct position. The mark on sproclet should align with mark on case.

Then you can go about timing the cams. It is a completely different procedure and measured in thousanths of an inch or mm.

And the variocam needs to have 3 bar pressure while you are doing procedure

Pete

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[Lear35A]

And when you do exactly as Pete describes...that engine, she purrs :-)

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