Cam Belt Tensioner

[colin944]

The tensioner needs to be set. But once you know its ok then its not so hard.I personally think too many people get caught up in the hype about belt tension. Yes is is important but it's also common sense and if you have done a few timing belts in your life then you won't have any trouble doing your 944 belts.


Here's a good guide of how it's done.

http://www.youtube.com/watch?v=o1P0n1DXMto

 

[sulzeruk]

Belt tension is critical Colin as too slack and you run the risk of twatting the valves with a flapping belt on a tight overlap engine or the belt jumping off, too tight and you end up running the bearings in the tensioners, idlers and water pump. If you do the 90 degree twist on the balance belt, it is far too tight, your car will be whining like a good one. It runs very slack, people are surprised how loose it is. Too tight on the balance belt as well and you will find it in the bottom of the plastic belt covers in pieces which can also break the cambelt leading to obvious consequences.
Alasdair

 

[colin944]

I understand that belt tension is important. All I am saying is that if you have done a few belts on various cars over the years then it need not be as complicated as it is often stated to be.My cars belts don't whine or make any undue noises. You can also always fit new belts and then have them check by a specialist if you are unsure or don't trust your own judgement.

 

[muzz]

I suppose when the car was new the spring tensioned the belt correctly, but still, checking the belt tightness
With the gauge again seems to make the automatic tensioner redundant. However I have done a few belts in my time and experience does count, also youtube has some good videos.
Thanks for the replies

 

[pauljmcnulty]

You can also always fit new belts and then have them check by a specialist if you are unsure or don't trust your own judgement.

Would specialists do this? I wonder how they'd work the small price they'd charge against any potential liability. Even if they weren't liable for any unexpected failure you can imagine the damage caused to them by "I had my belt checked by Blogg's Porsche, and 8 years later it broke. They refused to pay for a new engine, AVOID!! [][][]". As internet reviews tend to go.... [&o]

Given that the tensioning tool is available for only the cost of postage as a PCGB member, or postage plus a charity donation as a Tipec member, why try to guess it?

PCGB accept a charity donation as well. []

 

[colin944]

My local Porsche center would happily check my belt tension for me. The service manager knows it would take seconds to do.After all if you get them to fit your belts in the first place they will do a check for you after a couple of thousand miles.
Or you could join the Porsche Club and then get your RO to organise a trip to your local OPC the get them checked when they do the free inspections.

 

[pauljmcnulty]

My local Porsche center would happily check my belt tension for me. The service manager knows it would take seconds to do

Great, but surprising. Maybe I'm too paranoid! [&:]

I thought my indie factored in a hour to check/retension belts. Whilst I understand that's a minimum-charge rate, and would probably take less, what would be a realistic time to book a car in, get it in the workshop, do the check/tension, reassemble, and do the invoice and payment?

 

[colin944]

I suppose it depends on how well you know your local OPC .Living where I do the nearest Porsche specialist to me is my OPC. I always use them for parts ( or at least phone them for a price) and after being in and out of the place so many times you get to know who's who in the service / parts department ( I don't know any of the sales staff). They know I do all my own work and they are always happy to sit and talk Porsche when ever I go in. I think a lot of people are put off by the shinny corporate look and feel of the place but I've always found them to be really helpful and keen to know what I am doing to my car.Even if it is only a 944.
Maybe I'm just lucky and have a rose tinted view of OPC's ,but I can't speak highly enough of my one.

 

[pauljmcnulty]

Maybe I'm just lucky and have a rose tinted view of OPC's ,but I can't speak highly enough of my one.

Not at all, I think it's important to have that relationship with whoever works on your car, and that's my reasom for changing this year. I was no longer dealing with the people working on the car, nor the owners of the business, just their new middle-level people who were no use at all. No reason a main dealer can't be good at their job, or competitively priced!

My point was whether a Porsche centre, or an indie, would risk getting involved with checking, and perhaps somehow endorsing, a DIY job. Great if they do, but it surprises me they would risk it. You might be a great client, but if you sell the car next week with "recent belts, checked by Porsche centre xxxxx", that opens them up to an argument down the line.

Again, I think I'm being paranoid about it, and if you can get the belts checked locally then that's a plus for the diy-ers.

 

[zcacogp]

ORIGINAL: colin944

The tensioner needs to be set. But once you know its ok then its not so hard.I personally think too many people get caught up in the hype about belt tension. Yes is is important but it's also common sense and if you have done a few timing belts in your life then you won't have any trouble doing your 944 belts.

I agree. Timing belts are timing belts, and a familiarity with the way such things work will mean you are able to do the ones on a 944 pretty easily.

I suspect the hype about belt tension arose from the balance belt tension, which is very very loose. So loose it appears worrying the first time you see it. But - again - once you are familiar with it then you'll be fine.

My local indie (Tower Porsche in Bermondsey) is happy to check belt tensions for free. If you take the car to him and take the covers off he'll give you the five minutes needed to check it and even set it right if you ask him nicely. Interestingly, he doesn't use a tension gauge but does it by hand, and by running the engine and watching how much the belts flap around (answer: quite a lot).


Oli.

 

[colin944]

ORIGINAL: zcacogp

ORIGINAL: colin944

The tensioner needs to be set. But once you know its ok then its not so hard.I personally think too many people get caught up in the hype about belt tension. Yes is is important but it's also common sense and if you have done a few timing belts in your life then you won't have any trouble doing your 944 belts.

I agree. Timing belts are timing belts, and a familiarity with the way such things work will mean you are able to do the ones on a 944 pretty easily.

I suspect the hype about belt tension arose from the balance belt tension, which is very very loose. So loose it appears worrying the first time you see it. But - again - once you are familiar with it then you'll be fine.

My local indie (Tower Porsche in Bermondsey) is happy to check belt tensions for free. If you take the car to him and take the covers off he'll give you the five minutes needed to check it and even set it right if you ask him nicely. Interestingly, he doesn't use a tension gauge but does it by hand, and by running the engine and watching how much the belts flap around (answer: quite a lot).


Oli.

Nice to see you back Oli [][]

 

[zcacogp]

ORIGINAL: colin944
Nice to see you back Oli [][]

Thanks Squire.


Oli.

 

[Frenchy]

A friend used the official tool through the club after fitting and tensioning belts, turns out the belt had 90 degrees movement on the longest section after setting, seems to be a lot of opinions on this ?
Which clouds things ?
I have always done my own belts and used the 90 degree check at the centre of the longest belt section and no problems so far (fingers crossed)

 

[zcacogp]

90 degree check on longest run is what I always use for the cam belt, although the engine must be cranked through two full cycles after fitting the belt before testing it to ensure that all slack is taken out.

It's the balance shaft belt that's the odd one. And I can understand that the tensioner would be useful if you have never done that job before (although you probably wouldn't believe the readings the first time you do it!)


Oli.

 

[pauljmcnulty]

A friend used the official tool through the club after fitting and tensioning belts, turns out the belt had 90 degrees movement on the longest section after setting, seems to be a lot of opinions on this ?

Happy to give an opinion as someone who's never tensioned a belt in his life. [&:]

I'm sure that a "90 degree twist" is an accurate measurement if you do it every day. That's not a measurement that most amateurs would want to commit to, however, when there is a tool available for almost no cost that eliminates any doubt.

It might be over-kill to worry about getting it right. But, if it only costs the postage for the tool, against the nagging doubt of a bust engine, what's the reason NOT to check it properly? [8|]

 

[ChasR]

Without trying to ruffle too many feathers I was under the impression that the tensioning tool required checking for accuracy every so often. Is this done with the PCGB tool?

The 944 belt changes for an experienced mechanic do not seem to bad when they are changed or checked but special care is required with the balance belt in addition to the crankshaft bolt tightening torque which are two things which IMO can be easily overlooked.

I can however see where you are coming from Paul, especially if a novice mechanic is having a go with a 944 first.

 

[Veerzigzag]

someone who's never tensioned a belt in his life

Well if Paul hasn't done it, that's a very clear message to get it done by a specialist.....

 

[colin944]

I would say that if you have any doubts about it then get it done by a specialist. If you are in the habit of changing timing belts then see above for advice .We all have different levels of mechanical ability and if you don't trust yours get an expert in.

 

[zcacogp]

ORIGINAL: colin944
If you are in the habit of changing timing belts then see above for advice .We all have different levels of mechanical ability and if you don't trust yours get an expert in.

I'll go along with this ... getting in too deep with tinkering isn't a fat lot of fun and can be depressing.

However, I am quite a fan of the half-a-go mentality. 944's aren't hard cars to work on and you need to learn by starting somewhere. The more that simple jobs are wrapped up in a bit of black art and mystique the more people are scared off trying them. There used to be a lot of hoo-doo surrounding belts on a 944 - it was widely viewed as A Big And Difficult Job. Believing this, the first time the belts on my S2 needed doing I took it to an indie and paid him to do them - despite me having changed many cam belts on other engines (including a 928 S2) and quite a lot more. It was only talking the job through with the indie once he had done it that I realised it is pretty simple stuff and there is no black magic at all.


Oli.

 

[chrisg]

At the risk of being a huge sycophant, Mr Slippers makes a very fine and dandy point regarding 'black arts...'

For many years now I've been aware of the various mythical 'black arts' associated with IT, Law, Medicine, Car Mechanics, Plumbing, DIY..... and even bicycle mechanics !

What one realises after a while is that whilst there is a degree of 'art' to all these specialised areas they are still fundamentally done by a 'bloke' (or lady...) with training and expertise, none of which can't be learnt or mastered by someone with time and/or interest.

Half the problem with all of these areas or skills is the level of TLA's, jargon and general bollocks that is spoken which can confuse and confound Joe Public.

I've been lucky enough over the years to work with and alongside a number of skilled professionals who've kindly taken the time (particularly IT & car & bike mechanics) to translate technical terms into laymans speak....

When I first started tinkering with cars many decades ago, in particular race cars, there was a stage when I couldn't even load the car onto the trailer without ensuing panic or stress.....

So, to add to Mr Slippers point regarding the 944 engine and belts. Yes, it is a unique engine and has its own quirks and anomalies in particular the tension of both belts (esp. balance belt = lot looser than one would expect). However, fundamentally its still a standard (i.e. no VVT nor variocam/ vanos) a 4 stroke, 4 pot petrol engine. IMHO, as a 'weekend warrior' provided you follow the Clarkes manual and the Porsche workshop manual ( these are invariably written in a very stepwise fashion and intended for use by the lowest common denominator ie Workshop apprentice....) you shouldn't go wrong.

IMH experience, the biggest issue with working as WW is the lack of objectivity and also isolation. For example, being holed up in the garage in the depths of winter, well into a job and panicking/ stressing when something goes wrong.

I had this when I did the belts last winter....... Eventually worked out why I couldn't turn the engine over by hand (totally convinced i'd set the timing up wrong and the valves were up against a piston). Only to realise after a cup of tea and a breather, that the car was in gear with the handbrake on..... and thats why it wouldn't turn over by hand !Anyhow, as Oli points out: If you are attempting to do the belts, try it and then turn it over by hand using the front crank pulley nut. If all ok, pull the fuel pump fuse and disconnect the dizzy HT feed "" then crank the engine over on the starter. Assuming all ok, run up the engine to check the timing/ belt tension.

If you're still not sure about the tension or timing gently drive the car to you're local indie and pay them ~ £80 ( 2x hrs labour) to check it over !

Yours the humble Weekend Warrior