[ds968]

The balance belt check up AFTER the first 2 K miles re-tensioning is a factor of miles driven, not time ..so unless you drive over 10k miles a year I don't think there is any reason to check the balance belt annually . I could be wrong but I think they don't stretch with time, only miles.

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[flash]

it's that thinking that gets us into trouble.



rubber elasticity change is a function of time as much as anything else. that's just the nature of the material. that requires a tension check at periodic intervals.



over-simple proof of this is the "set" that belts take when they have been sitting for a long time. they form to the size and shape of the pulleys. zero miles, but a very definite change in the material.

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[ds968]

Like I said, I could be wrong...it's just that typically rubber when not in constant use tends to become more rigid / shrinks rather than be more elastic / expand.

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[SamSparks]

The Porsche Timing Belt Tension tool P9201 appears to be the generally recommended belt tensioning tool. Clark's Garage prefers this tool but mentions aftermarket tension tools i.e. Optibelt, Market as alternatives (I can't find the 'Market' tool using Google). The Arnnworx tool (920Xv6 Timing Belt Tensioning Tool - Version 6.1?) has been mentioned elsewhere on 968Forums. Given the cost of the P9201, are any of the alternatives worth considering?

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[Bulti]

http://youtu.be/o1P0n1DXMto



I should try without the/a tensioning tool, it can be done without it if you know how. It's a bit trial and error but definitely doable.



The guy in the vid is checking the belt tension at 19:10. You get a clear look where he checks the tension and how. If your German is a bit rusty (mine is): he tells to take the belt between your thumb and indexfinger. When you can twist the belt about 135°, the tension is fine.



A little bit of adjustment can be needed, but it's a good reference point.



I used this method and everything is a-ok.

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[flash]

since the timing belt itself is hydraulically tensioned, that leaves only the balance belt requiring tensioning. that's actually pretty easy to do without the tool, if you have good sensitivity in your hands. if you don't, you could be at it all day. the above method is pretty accurate. i would add to that another method, which is to push the balance belt toward the waterpump, and with minimal pressure, it should be able to touch it. take care to get the measurements right, and note that the pic in the manual is a bit deceiving. the 1mm dimension is not a clearance, but a deflection measurement.

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[SamSparks]

[quote name='flash' timestamp='1405031499' post='159931']

since the timing belt itself is hydraulically tensioned, that leaves only the balance belt requiring tensioning.  that's actually pretty easy to do without the tool, if you have good sensitivity in your hands.  if you don't, you could be at it all day.  the above method is pretty accurate.  i would add to that another method, which is to push the balance belt toward the waterpump, and with minimal pressure, it should be able to touch it.  take care to get the measurements right, and note that the pic in the manual is a bit deceiving.  the 1mm dimension is not a clearance, but a deflection measurement.

[/quote]



Flash,



Many thanks for clearing that up!



The results of my web-research and preliminary reading of various how-tos were ambiguous (at least to me) - some seemed to indicate the timing belt needed to be tensioned, others said no, just the balance belt.



Regards,



Sam

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[SamSparks]

[quote name='Bulti' timestamp='1405030034' post='159928']

http://youtu.be/o1P0n1DXMto



I should try without the/a tensioning tool, it can be done without it if you know how.  It's a bit trial and error but definitely doable.



The guy in the vid is checking the belt tension at 19:10.  You get a clear look where he checks the tension and how.  If your German is a bit rusty (mine is): he tells to take the belt between your thumb and indexfinger.  When you can twist the belt about 135°, the tension is fine.  



A little bit of adjustment can be needed, but it's a good reference point.



I used this method and everything is a-ok.

[/quote]



Phillipe,



Many thanks for your very helpful reply.



My German is very limited but my reading of body language is passable. <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />



Best wishes,



Sam

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[SamSparks]

Another (dumb?) question if I may.



(Please bear with me as I go up the learning curve. As my much-loved 968 nears its 20th birthday I am keen to understand the real-world feasibility of keeping it a-rollin' an' rumblin' on when professional support for what is essentially an 'obsolete' car becomes ever harder to find).



My question is: In order for the timing and balance belts to be replaced, is the flywheel locking tool necessary? In other words, can the belts be removed (and new ones fitted) without removing the crankshaft pulley bolt e.g., by removing the tensioner rollers?



Many thanks in advance



Sam

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[Bulti]

If you want my advice: buy the tool, it's not that expensive. It can (and will) save you A LOT of trouble.



When I changed belts I took the opportunity to change all front engine seals, rollers, waterpump and such. The tool is a great help. You can always try to sell it afterwards if you don't like it sitting on your garage shelf :-)



Like you said, the beastie is 20 years old. Therefore it's best not to cut too many corners. Always do the 'while you're in there' stuff. It's more expensive and labour intensive but in the long run you will be happy to have done it. Especially if you plan on keeping the car.



IMHO

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[chamm]

I bought and used the flywheel lock and still tried to get the old belt off without removing the crankshaft pulley bolt. (I must have read somewhere that it was possible on a 944). I was unable to get the old belt off without removing the crankshaft bolt -- there's just not enough clearance.

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[SamSparks]

[quote name='Bulti' timestamp='1405074801' post='159945']

If you want my advice: buy the tool, it's not that expensive. It can (and will) save you A LOT of trouble.



When I changed belts I took the opportunity to change all front engine seals, rollers, waterpump and such. The tool is a great help. You can always try to sell it afterwards if you don't like it sitting on your garage shelf :-)



Like you said, the beastie is 20 years old. Therefore it's best not to cut too many corners. Always do the 'while you're in there' stuff. It's more expensive and labour intensive but in the long run you will be happy to have done it. Especially if you plan on keeping the car.



IMHO

[/quote]



Phillipe,



Once again, many thanks for your invaluable advice - and for taking the time to reply.



I'll buy the tool.



All seals, pulleys, tensioners and the water pump were replaced by Porsche about 1k miles ago. The proposed replacement of belts is purely an age-related thing.



I really want to keep the car - but the approaching 20th anniversary of ownership has prompted a review of the realism of keeping the car in top condition without professional support.



I was a good mechanic back when I was a teenager, but haven't wrenched anything since - always paid pros to do so, and in the case of my 968, always paid Porsche to do so.



As Dirty Harry said, 'A good man always knows his limitations'.



Best wishes,



Sam

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[SamSparks]

[quote name='chamm' timestamp='1405082477' post='159946']

I bought and used the flywheel lock and still tried to get the old belt off without removing the crankshaft pulley bolt. (I must have read somewhere that it was possible on a 944). I was unable to get the old belt off without removing the crankshaft bolt -- there's just not enough clearance.

[/quote]



Hi Chamm,



Many thanks for your excellent insight. Just the kind of real-world, experienced perspective I was looking for.



So, I will get the locking tool.



Just a thought: Could you have cut the belt off?



Best wishes,



Sam

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[cosimo]

Looks like at least 4 valves bent. Just going to replace them all and have the head remilled. All the other work will be rather routine, i.e motor mounts, knock sensor, oil pan gasket and anything else Ivan might see that needs immediate attention. I will need a new clutch but it hasn't done any slipping or unable to get in gear, so I'll put it off for a while.

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[tryan]

I have a 92 that just rolled over 90k and the belts where last replaced in 2003 at 75k. The variocam pads have minimal wear and the balance belt is slightly on the loose side ie 110 degree twist..... so 15k miles and 11 years..... yes 11 years and no micro cracks or ozone degradation.... note that no oil has been slung onto the belt.



Car was from the Midwest. The cam cap bolts are loose and waiting on parts the OEM Porsche belts, cam chain and a seal kit. There is a slight leak from the upper balance shaft.



Got a Taiwanese xzn set off amazon and bought a pos handheld chink impact from orieys....none of the cam cap bolt heads stripped. No offence to the Chinese but the impact driver fell apart when I tapped on it with a 2 pounder. Lol)) kinda want the cam hold down tool but I will get over it.



There is a tensioner tool on eBay right now but I am thinking the arnworks version. (their power steering return line repair works awesome btw)





Edit: I love that guys videos, not as good as Van's but he has a man's man cheater bar!

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[flash]

yikes!!!! 11 year old belts??? get those belts done NOW! they are not safe after 4 years, regardless of the fact that they only have 15k on them. you cannot see the problems with them. it's an polymer / elasticity thing. way too many horror stories about 5 year old belts, including mine with only 25k on them.



note: whatever wear you have on the upper variocam pad, realize that you have twice as much on the lower one. that's just the way it goes.

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[ds968]

Keep in mind another thing - the belts may have been sitting on a dealer shelf as long as 6 years before being sold and installed in the car, so you COULD have 17 year old belts in that car. ( six years "shelf life" is the maximum recommended allowance by Gates to their dealers, but if you have Contis or something else in there which are , reportedly , unlikely to be as well built as Gates are.....tick, tick, and it's a $ 6,000 job ! )

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[tryan]

Yep, 11 years.... changing the pads and chain also. Sprockets look good. No shiny spots. I think the <acronym title='previous owner'>PO</acronym> drove the car so long with a bad hall sensor that there wasn't much load on the valvetrain)) doh)) dude rode the clutch so bad that there was a hole in the floormat. It looks like it was a hate/hate relationship with the dealership service.... but it was all on schedule except for the last ten years.

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[tryan]

Mr Sparks, yes, you can cut the old belt but the sprocket still needs to come off to install the new belt. Sometimes you have to skin the cat)) Unlike the 944 and previous variants, the timing belt tensioner is automatic on this motor.. No need for the tensioning tool on the timing belt but you will need it for the other balance belt and ancillaries. The Porsche tool is expensive (there is one on eBay) and the cricket thing looks pretty cheesy and possibly inconsistent. Look at arnworks offerings and I think there is value and quality in his products.

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[flash]

unfortunately, when porsche wrote the schedule, they really didn't have enough data to work with. since then, we have made some "changes" to that schedule.



you can get around the tensioning tool for the balance belt and such, assuming you have some sensitivity in your hands. some of us can even torque things by had within a pound or tow, because we've been doing it so long. it's really no different than having an accurate golf swing or tennis stroke. after you have repeated the same thing enough, you know how much force to use. it's called "muscle memory programming"

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