[salmeronjs85]

Does anyone know where i can find instruction on how to replace the timing belt and balance shaft belt. greatly appreciated

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[flash]

it's in the workshop manual



you will also find quite a bit on it if you do a search here

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[Cloud9...68]

I could have sworn there was a DIY specific to the belts, but I couldn't find one. But, this DIY for the water pump replacement covers all the steps for the belt replacement, since you have to remove the belts to get tot he water pump:



http://www.968forums.com/topic/3249-wate...placement/



The description is pretty brief and concise, so let me add a few things that you might find helpful:



1. If you're not planning to replace the water pump, skip the step that says to drain the coolant.

2. I would recommend that you remove the fans, as they are just held by a few screws, and getting them out of the way gives you a lot more room to work. No need to disconnect the fans; just move them out of the way. No need to remove the radiator, either.

3. The pulley is on very tight - I can't remember the torque spec (look that up in the workshop manual; if you can't find it, I'm sure someone on this site knows it. I can look it up if you can't find it anywhere else), but you won't be able to get the bolt off without a breaker bar plus a long pipe, or an air wrench. Also, I think the pulley is held on by a 27 mm nut.

4. Don't even think of trying this job without a flywheel lock. I know some people have done it, but I wouldn't take the risk of damaging the flywheel teeth. I think they can be had for less than $100; it's one item that I think has actually gone down in price lately.

5. Adjusting the balance shaft tension is one of the most frustrating parts of this job. Consider buying the flat, slightly curved wrench that's specially designed for this job. It makes this task a lot easier. I know Paragon carries it.

6. I would urge you to make drawings of the balance shaft and timing belt assemblies before taking the belts off. Don't rely on your memory of how they should go back on; its' much less stressful to have a picture to go by.



That's all I can think of off hand. It's not really that difficult of a job, just very time-consuming. Take your time, take breaks whenever you get stuck or frustrated, and you should do fine. This is one of those jobs where you have an opportunity to save a ton of money by doing it yourself, with minimal risk of screwing something up. Good luck.

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[salmeronjs85]

thanks for the help!

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[flash]

there isn't a DIY because the workshop manual is pretty good, and everybody has it or can get it for free - no need in reinventing the wheel - there has been one DIY on it floating around, but it isn't very good, and it gives some really bad instructions on some mickey mouse steps

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[DaveN]

If you do your own belts make sure to mark everything BEFORE you take the old belts off. We didn't and upun reassembly could find absolutely no markings for TDC. You know what they say about assume <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> Removed the starter and cover and nothing on the flywheel either. Had to do it the old fashioned way, flashlight and a screwdriver down the spark plug hole. On an interference engine that makes me nervous.

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[Cloud9...68]

DaveN-



Good point about the TDC. There are several TDC markers on this car, and there appears to be some inconsistency as to how many of them are present. Not all 968 have all the markers, in other words. On my car, there is a handy window in top of the distributor cap which is covered by an easy-to-remove rubber cover. To find TDC, remove the cover, and rotate the engine until the mark on the camshaft gear lines up with the notch in the distributor which is visible when the rubber cover is removed. According the the manual, to be certain the engine is at TDC, the rotor needs to be pointing straight up when the marks described above are aligned. So, the overall easiest way to find TDC is to remove the distributor cap, and rotate the engine until these two conditions are met.



Another way which I think is available on all 968s is to look at the mark which is visible through an opening in the top of the bellhousing. This opening can be seen by looking straight down just behind the oil fill cap, and just a bit toward the right of the car (iirc). It isn't the easiest thing to see, as the view is partially obstructed by the throttle cable and its bracket. Supposedly, when the engine is at TDC, a mark will be visible through this opening. I didn't use this method when I replaced my belts, but the next time I do it, I will use the method described in the above paragraph, and then check the opening in the top of the bellhousing to see what type of mark appears.



On my car, there are no marks whatsoever in the bellhousing in the starter opening, although I've heard that some cars have them. Using these marks, if they exist, strikes me as a royal pain, as it would entail repeatedly crawling under the car to check the marks.

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[Ryan]

Here we go again. The confusion about the timing marks....



Here is a view under the car and you see the oil pan and the flywheel cover behind it. There is a small plug (if still there) that can be pulled to show the mark on the flywheel. The starter does not have to be removed as you can see its backside in the picture. Still a good idea to use a combination of these marks to be sure you are on the right stroke of the engine. I like to stick a stiff wire down the #1 spark plug hole to show it at the top of the stroke as well.

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[Cloud9...68]

Hmmm... I'll have to look for this mark the next time I'm under there. But with the marks on the distributor, and the one at the back of the engine, it would seem that there are plenty of ways to make sure you're at TDC without having to pull a spark plug or repeatedly dive under the car. In fact, even if you have it wrong, and you're off 180 degrees, it probably won't affect a simple belt change, because all you have to do is make sure nothing moves from where you had it set when you applied the flywheel lock. The lock guarantees the crank won't move, and you'd really have to try to move the cams. That leaves the balance shafts, and as long as you don't allow them to rotate away from where there were when you took the belt off, you'll be fine.

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[Ryan]

Cloud, I usually pull the plugs in order to turn the engine easier anyway.

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[Cloud9...68]

Ryan,



That's fine; lots of people do that, as it really does make the engine a lot easier to turn. Personally, though, I like to remove and replace the plugs from our priceless aluminum heads as infrequently as possible, although I'm sure my fears are based on ancient data from inferior aluminum alloys from decades past...

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[flash]

the fear is also generated by the experiences of those who forget or neglect to use anti-seize on the plugs, and then fail to use a torque wrench to reinstall them

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[Scott Collins]

I have pulled the plugs to hand crank the engine - much easier. I once was trying hard to hand crank the thing after getting the belts back on and attempting to adjust the balance shafts, and the engine would not crank at all. Took the plugs out, and she still would not crank. I braced myself against the wall for more leverage, but still no dice. Turns out, it works better if you take the car out of gear....

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[Peter]

I am preparing to replace the belt for the first time. I think I know the theory of replacing the belts but I have a couple of questions to those who replaced the belts by themselves: I would greatly appreciate if you share your experience and answer the questions below:



1. What was the most difficult step, meaning a potential show stopper?

2. What is the chance of getting stuck while removing or installing the belts?

3. How hard was to break lose the nut on crankshaft pulley?

4. What length (feet) was your breaker bar with the leverage bar/pipe?

5. Do you break lose the crankshaft nut from beneath or from the top of the car? Any special technic?

6. Have anybody set the tension of the balance belt by using a different than Porsche device?

Thank you.

Peter

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[salmeronjs85]

ok people so im stuck at the step were u loose the tension from the hydraulic tensioner . any help???? - thanks

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[Cloud9...68]

You have to remove the tensioner. Then, to put it back, you have to compress it using a vise, and stick a pin through the hole in the tensioner to maintain it in the compressed position, install the belt, reinstall the tensioner, then pull the pin out. At least that's how I remember it...

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[DaveN]

Remember that when you recompress the pin you have to do it VERY SLOWLY and patiently then put a pin in the hole; don't rush the recompression.

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