Changing belts and chain (S2) - hints and tips?

[zcacogp]

Chaps,

I'm all set to change the belts and cam chain on my S2 towards the end of this week, or possibly this weekend. I have a new belt and rollers kit, and a new chain, turning up today or tomorrow from Promax, as well as a new waterpump and new cam chain slippers (although these are on sale-or-return as I am not sure whether they will be necessary - thanks Andy Everett!)

I have changed a number of cam belts before on other vehicles but have never done one on a 944. What should I look out for? I have read (and will print out) the Clarks Garage articles and the only thing in there that looks worrying is the mention of a flywheel lock. I can see that one of these will make the job a lot easier, but is it possible without one? Can I make one? It sounds like a plate that bolts in place of the starter and holds the flywheel solid. I have made a similar such thing for a 928 when doing the cambelt on that, so I can't imagine it would be impossible on a 944.

I won't ask the question about belt tension here, as it has been asked numerous times on other threads before. Suffice it to say that I am happy I can tension the belts myself, but will take it to my local indie (about 3 miles away) to be checked as the first journey with the new belts fitted.


Oli.

 

[robwright]

IMHO mate no need to worry about the flywheel lock I think Clarke just covers himself and does everything more less as per Porsche on the website. What he does in practice may be a different thing. Do all the usual things and you will be OK. I found it really helped to accentuate the timing marks with white metal paint. Especially the balance shafts. These are only held by the belts and will rotate as soon as you remove them because of the counterweights.

 

[pegasus]

Its all pretty basic stuff,do it properly and dial the cams in or you will never know if they were or are timed exactly,all the best John.

 

[zcacogp]

Thanks for the comments chaps.

What do you mean by "dial the cams in" john?


Oli.

 

[xenon]

Good luck, Oli. I'd be interested how easy it is to get the cams out.

 

[zcacogp]

ORIGINAL: xenon
Good luck, Oli.

Flip me Ian! Such words have me thinking I'll need luck to succeed! Care to add "... and may the force be with you" as well ... []

(I'll be sure to keep you posted. In fact, I may even take some photos. [] )


Oli.

P.S. And thanks for the good wishes!

P.P.S. I do have memories of a chap on here posting photos of the cam change on his S2 where he raised the cams end-first, and managed to snap a flange half-way down them in half as they were meant to come out very vertically. It's visions of this sort of thing that make my blood run cold ... []

 

[xenon]

I'm sure it will go swimmingly. I toyed with the idea on mine when I changed the slippers. I would like to have changed the roller chain too but taking the cams out (and putting them back in again) seemed a bit daunting.

 

[zcacogp]

You're doing it again! "Seemed a bit daunting" ... What am I letting myself in for?!? []

Looking at the design and write-ups, I can't understand why they didn't install a split-link in the chain, or provide a tool for taking a link out (in much the same way as you can with bike chains.) That would alleviate all the hassle with changing it. I suppose it's partially down to the fact that Porsche never recommended changing the chain, and also that a split-link would be a weakness, which should be avoided.


Oli.

 

[xenon]

In that case I won't even broach the discussion that changing only one contact item (the chain and not the sprockets) might exacerbate wear during a new bedding in process.... [X(]

 

[zcacogp]

Erm ... >cough< ... I thought that the advice was to change the chain often to preserve the sprockets?


Oli.

 

[xenon]

I honestly don't know []

I know most motorbikalists change sprockets and chains as a set.

 

[pegasus]

Hi there, If you go through the workshop manual you will see the procedure for timing the camshafts properly,the readings are there,they differ for the s and s2. There are slots on the top pulley that allow the cams to move slightly so that you get the exact timing for the cams relevent to the crank. I say cams as you cannot adjust each cam on its own only as a chain coupled pair. You have to do this as you have no way of knowing that the timing was correct to start with and buy keeping the adjusting pully locked any error will be kept,it is very easy to do and at least you will know that is is correct and have the satisfaction of both the dail gauges and tdc marks marching to the correct porsche tune. all the best John.

 

[pegasus]

found a picture

 

[FistsOfHam]

ORIGINAL: pegasus

Hi there, If you go through the workshop manual you will see the procedure for timing the camshafts properly,the readings are there,they differ for the s and s2. There are slots on the top pulley that allow the cams to move slightly so that you get the exact timing for the cams relevent to the crank. I say cams as you cannot adjust each cam on its own only as a chain coupled pair. You have to do this as you have no way of knowing that the timing was correct to start with and buy keeping the adjusting pully locked any error will be kept,it is very easy to do and at least you will know that is is correct and have the satisfaction of both the dail gauges and tdc marks marching to the correct porsche tune. all the best John.

Well when you put it like that I don't know why we aren't all doing it []

 

[bertelli_1]

Just to add to what pegasus has already said, the keyway in the cam pulley is wider than the woodruff key & can rotate quite a way on the camshaft. The 3 eared thingy the rotor arm bolts to does not rotate on the camshaft, the keyway is the same size as the woodruff key, you will notice when stripping it that the cam pulley has slotted holes where the rotor arm bolts through it. The witness marks from the bolts give a good indication of where to place the cam pulley on the cam, however this is not an accurate way of setting the cam timing!!!!!
Also, before removing the cams it is worth taking a pic of their position, make a mark on the cams and count the number of chain links between them, hopefully making re assembly easier.

 

[bertelli_1]

Just to add - be careful when removing the tensioner oil feed pipe, it is very easy to drop the copper washers which then end up in the sump. Not that i've ever done that of course........

 

[pegasus]

There is no need to get snotty it IS an easy job, as for witness marks, if you want to put it back as it was without knowing if it was ever right it is up to the individual but if you do it properly you will know exactly what is going on.If you want to get all you can out of your engine for no expense set it up properly,this is why some cars just go better than others,all the best John.

 

[JamesO]

It is an easy job if you have the correct tools, like most things in life. The hard bit is gettting the dial guages set up steadily in the first place as you need to find a way to mount the two guages to the head, that is the tricky bit.

 

[pauljmcnulty]

Just to add to what pegasus has already said, the keyway in the cam pulley is wider than the woodruff key & can rotate quite a way on the camshaft. The 3 eared thingy the rotor arm bolts to does not rotate on the camshaft, the keyway is the same size as the woodruff key, you will notice when stripping it that the cam pulley has slotted holes where the rotor arm bolts through it. The witness marks from the bolts give a good indication of where to place the cam pulley on the cam, however this is not an accurate way of setting the cam timing

As someone who's experience is limited to tyre pressures, oil level etc. it's actually very scary that this could be considered "easy". [&o]

For those who are happy to do this kind of work, on any car, don't forget that there are two tensioning tools free to borrow from the Club. Tref normally has them both in action on his cars...[]

 

[rcsalmons]

Oli.

Biggest trouble I have had doing this job was removing the cambelt gear from the crank, managed to borrow a gear puller from a mate but had to remove the rad. Saying that when I have done it on other cars it has come off really easy.
Definately worth trying to borrow a flyweel lock the crank bolt is very tight.

Rich