16v cam chain reliability

Hallsy · Sep 18, 2013

Whenever I get a new car, I like to deal with the achillies heels straight away, for peace of mind - specifically to the 16v engines I see that as being the cam chain setup.

My question is, in reality does the actual chain often fail or even just stretch enough to cause timing issues or excessive wear? My 944s is on 128k and can find no record for cam chain so will assume it is original. The top slipper pad was replaced in 2006 at 117k.

I plan to replace the bottom slipper and will probably put a new top one in again, even though it has recently been done, for the price and fact I'll be removing tensioner, etc - I feel that I may as well do it again.

I also plan to replace the chain but with the extra labour involved, it makes sense for me to plan it in with a belt change. The belts were last done at 126k in 2011. I don't do many miles so will likely be replacing the belts again in 2015 with probably another 10k miles or so added in that time.

Does that sound sensible, or at this age/mileage is the chain itself likely to be in desperate need of replacement?

robdimond · Sep 18, 2013

I think that sounds very sensible to combine the chain with a belt change.

I replaced my chain at 186k miles and it had stretched to the point the tensioner was barely doing it's job, right at the limit of it's travel. The big weakness is the plastic slipper pads.

chrisg · Sep 18, 2013

I'm no expert on this things, but I think for the sake of a few quid replacing the chain is a good idea "whilst you're in there".

From what I know about the S2 system (haven't had an S2 for a few years but had the slipper pads done immediately when I first bought it), its the pads that wear out allowing the chain to slap about leading to slip and broken teeth on the cams= this is when it gets expensive as the cams are £££

The 944 engine is actually pretty bullet proof, provided the S2 Chain/slippers and the belts are done at the appropriate intervals.

Yours

Chris

robdimond · Sep 19, 2013

I wouldn't say the chain is a WYIT job when doing the tensioner slippers.
The chain is cheap (£20) but changing it requires removing the cams, so you're slackening the timing belt, removing the front bearing bridge, taking off the cam sprocket... lots of work.

Taking out the tensioner is by comparison a quick and easy job as long as you avoid the common pitfalls: dropping bolts/crush washers into the oil drain holes or stripping out threads.

If the top slipper has been done recently I'd be tempted to do the whole lot in the next belt chain: both slipper pads, chain and belts.

TTM · Sep 19, 2013

The thing is that the slippers seem to wear out at a much different rate from an engine to another.

I did about 100k miles with my S2 and whenever I took the head cover off the pads always showed minimal wear. Still replaced them since I had everything apart...

SUSIT · Sep 19, 2013

on my second S2 the first one had the cam chain and slippers go at 133 000 the resulting damage took the head out and snapped teath on the cam drive gears. I later read on this site that the chain is not a service item but tend to fail around 130 000!! My second S2 i purchased a vyear ago with 117000 on the clock but before i did anything with it the chain and slippers were done, best 150 quid for peace of mind i have ever spent.

New cams from Porsche are £500 each but I suppose if it goes wrong you buy another second hand engine!

Hallsy · Sep 19, 2013

Well I have a new pair of slipper pads on order and will be replacing those, but the chain (unless obviously worn) will wait until I next do the belts.

I'd imagine that most failures are down to pad breakup rather than the actual chain - hopefully I'm right lol!!

J.C944TurboMan · Sep 20, 2013

I have a brand new original chain tensioner on offer ? I bought it with the intension to fit it to my S2 , but the one on my car had already been replaced with original equipment , so it is surplus.
It is listed hear on the forum under items for sale and also on ebay.
Bargain price thanks.