Belts and Chain - DIY?

[WillJ]

Hi,

It's about time to do the belts and chain on my 944s2. Unfortunately it's not got any cheaper since I last had it done.

With that in mind, how difficult is it to do yourself? I guess my enthusiasm is greater than my ability mechanically, but I'm no idiot. If it's just a case of following clarkes garage and you tube to the letter, I'll probably give it a go, but if black magic and voodoo is necessary I guess I should get the wallet out.

I have all the normal tools, but no pit or lift so getting under is tricky if required...

Thanks

Will

 

[timmyturtle]

Its one of those jobs that really needs doing properly. Not beyond a competent DIYer with a good set of tools, however, you dont have much scope for mistakes

 

[pauljmcnulty]

how difficult is it to do yourself

This comes up regularly, and I guess we fall in to two camps. Some, like me, have never tackled anything this major, or with the potential for disaster, before. I don't have a garage, any of the right tools, or the skills, so it would be a very big leap for me to try it.

Others are happy that the 944 isn't much different to other engines, so if you've changed a few belts in your time, and are happy to follow the guides and be methodical, there's no reason not to DIY. Needing the chain as well adds another level of difficulty, I guess?

The Club has the tensioning tool available to members to borrow for the cost of postage, and some indies will check the tension for a small fee.

Another option is if you have a local mechanic you trust who's a lot cheaper than a Porsche specialist, or Porsche themselves. He should be able to take it oneasily enough, and again the options to check the tension properly are both there. The trouble near me is that even the scruffy little workshop I use for the van is nearly the same price as the Porsche specialists, so their experiance makes them faster, and actually cheaper!

 

[ChasR]

Surely this should be part of the FAQ.

As above really. If you have fiddled on a car before and have experience of doing belts the 944 is not too awkward at all. The tensioning requires a little attention as does the crankshaft nut torque (alot higher than other cars and it is crucial it is tightened to the correct torque since the oil pump will not be driven if the bolt is loose, leading to potentially disastrous consequences).

Saying that, many other cars these days probably are more awkward than the Porsche IMO. Fords for example require all of the pulleys loosening, the timing tools putting into place with the crank and cam pulleys being retightened (with none of the sprockets having a woodruff key). Renaults and now VWs are also similar (with the tippex method (purely to test it) we found a belt to go out 2 teeth on a VW PD engine as opposed to the locking tools being used). Alfas are even worse and possibly one reason why they have the 'unreliability' tag (dial gauges etc. are required for the Twin Spark and V6 engines, with costly consequences on the latter (burnt valves and lower power figures)). That's before you get to space issues (Renault say the Clio 182 is an engine out job, although many specialists do change them in situ, albeit with all of the mounts loosened off).

Specialists can be cheaper than a local garage though and you will have some peace of mind to them doing it.

 

[colin944]

As above. Think of it this way.......... Are you willing to risk your £1000 ish engine on a job that may cost £400 - £500 at a specialist or £150 ish if you do it yourself?

I did mine( inc the chain) and will be happy in the future to do them again.However if you have any doubt on your mechanical ability then leave them alone and pay a specialist.

 

[zcacogp]

There is no voodoo or black magic. If you are practical and have changed belts on other cars before then you won't struggle with those on a 944. Really, keep your money in your pocket, set aside an afternoon (you need to take a surprising amount of plastic off the engine to get to the belts), buy the parts from Frazerpart or someone like that and do it yourself. Put the savings into the beer fund.

Getting the belt tension right is important, but it's no harder than on any other car. Quarter-twist on longest run is good to aim for. The only difficult one is the balance belt tightness, as it needs to be much, much looser than you'd expect. Look at the old one before you take it off. If you aren't familiar with belt tension then borrow the tensioner tool from PCGB, or trundle down to your local indie once the job is done and ask them to check them for you.

ORIGINAL: ChasR
... it is crucial <that the crankshaft nut> is tightened to the correct torque since the oil pump will not be driven if the bolt is loose, leading to potentially disastrous consequences.

I'd slightly disagree with this; the crankshaft bolt is VERY tight and you need a long breaker bar to undo it. However I have never bothered to torque it back up once the job is done - I've just done it up as tight as I could get it and left it at that. Correct torque is something like 850NM, so I've headed for 'Ba5***d Tight' and it's worked.


Oli.

 

[ChasR]

ORIGINAL: zcacogp

ORIGINAL: ChasR
... it is crucial <that the crankshaft nut> is tightened to the correct torque since the oil pump will not be driven if the bolt is loose, leading to potentially disastrous consequences.

I'd slightly disagree with this; the crankshaft bolt is VERY tight and you need a long breaker bar to undo it. However I have never bothered to torque it back up once the job is done - I've just done it up as tight as I could get it and left it at that. Correct torque is something like 850NM, so I've headed for 'Ba5***d Tight' and it's worked.


Oli.

That is a fair point. I guess that I have always been a little belt and braces when changing cambelts on cars with regards to torque figures and maintaining the correct timing .

However, is not the correct torque for the crankshaft bolt 210NM? Any half decent torque wrench (or breaker bar) should suffice there, or as tight as you can get it should do the trick I guess (I only said the above after people noted a drop in oil pressure after having their belts changed).

 

[Frenchy]

Yep 210 Nm, a flywheel lock tool is an absolute winner when loosening and tightening, make sure you get it tight as mine came loose, luckily on the driveway so no damage done [] and it was bloomin well tight, now torqued to 210 Nm.

 

[robdimond]

I did this myself as part of a water pump and front engine reseal. It is a lot of work doing it yourself... satisfying but doesn't save any money if you value your time!
I would not attempt if you've not done a timing belt before on any car. Easy if you know what you're doing and it goes well but it can get very hairy very quickly.

The Clarks garage guide is accurate, I recommend the tip about using bolts to lock the camshaft pulley and preserve the fine timing adjustment.

A flywheel lock is the only essential special tool. Invest in a very good quality (I used german stahlwille ones) 10mm and 8mm triple square bits to undo the camshaft bearing bolts and the camshaft pully bolt (which is very very tight!).

Taking the cams out (essential to do the chain) without the special tool is very doable but you need to take care... they need to come straight up or they will bind in the head. Remove the front bearing bridge first, it is stuck on with loctite and is a pain to remove.

 

[zcacogp]

ORIGINAL: ChasR

However, is not the correct torque for the crankshaft bolt 210NM?

Nope, it's much more than that. Last time I looked at the Porsche Workshop Manual it listed it as "FatGitOnTheEndOfA4FtBreakerBarSweatingAndSwearingUntilIt'sDoneUp"NM, and so I did what I could to oblige.


Oli.

 

[924nutter]

Working on the principle if you don't undo it you don't need to tighten it up, on a hot day I managed to wiggle my belt around the bottom pulley by easing the lower cover back until there was just enough room to pass the belt through.

 

[tref]

Yep, after years of me removing the bottom pulley, this was demonstrated to me by some-one changing their belts for the very first time. I had heard rumour it could be done, and had tried and tried, but never figured out how... Fortunately, he remembered how he had done it, and if I seem to recall the trick is to leave it in place around the tensioner and water pump, and that holds the belt at the right angle to allow you to twist it sideway and slide it out of the case - no need to mess about with the bottom pulley.

 

[zcacogp]

ORIGINAL: tref

Yep, after years of me removing the bottom pulley, this was demonstrated to me by some-one changing their belts for the very first time. I had heard rumour it could be done, and had tried and tried, but never figured out how... Fortunately, he remembered how he had done it, and if I seem to recall the trick is to leave it in place around the tensioner and water pump, and that holds the belt at the right angle to allow you to twist it sideway and slide it out of the case - no need to mess about with the bottom pulley.

That sounds very interesting Tref, thanks. Changing the belt without removing the bottom pulley would be a nice trick to have up one's sleeve. (An aside; you don't need the flywheel lock to remove the bottom pulley - it can be done with the car in gear and the handbrake on, but the flywheel lock helps quite a lot.)


Oli.