944S (probable) cam belt woes

[millimeep]

Went to a funeral up in the Bedford/Cambridge area today, about a 60 mile drive, our 944S was fine on the way up, no problems as usual.

Back to the house for sarnies, and it was time to go home.

Didn't get as far as the end of the road and the car stalled, tried to restart only to get that horrible really fast no compression spinny sound []

So one train journey home, we're here and our '88 944S is there and we're wondering what to do next...

I'm quite happy with mechanics, I've been working on my own cars on and off for 20 years now, just wondering how involved a cam belt change in the drive will be?

(well I know it's going to be quite involved, I've been looking around the old threads)

What's the easiest way to check for the dreaded valve/piston damage?

Failure happened at very low speed, <10mph, <1500rpm.

As I've said it's the oval dash 16v 2.5 944S

Option 2 is selling it... what would it be worth as a project?

Here's a picture of it in happier times!

Edited to add more info:

Just been perusing the history, at the March '06 MoT it had about 164,000 miles on the clock, now it's about 178,000

The belts, tensionsers and idler pulleys, and balance crank shaft pulley were done almost exactly 3 years ago on the 16/5/2006

So that makes 3 years/14,000 miles so I wasn't late on the service!

 

[tref]

Since you haven't had any other replies yet... I guess the first thing is to confirm your suspicions (and I have a feeling you are right). I guess the easiest way of doing that is to remove the tell-tale bung from the top of the cam belt housing and confirm there isn't a belt in there. From what I have heard, even at low revs I would be very surprised if you got away without at least one bent valve. A bent valve means the head has to come off as a minimum. The good news is that this is still perfectly feasible on a drive-way, as is the subsequent refitting of the belts etc. I guess you then have to evaluate what the car is worth as it is compared to what the car is worth fixed, and the cost of the work. Another option that may be worth considering, how-ever, is to replace the engine rather than do the head-work - it could easily work out cheaper. This is also perfectly feasible on a drive-way... and doing the belts is a lot, lot easier with the engine out of the car!!! Regards, Tref.

 

[Frenchy]

What Tref said, good luck with it !

 

[andy watson]

If after checking through the inspection bung if the belt is presant, remove the cam cover you may find that the cam chain slipper has broken causing the chain to snap. This I know from experience and replacement engine, unfourtunatley whilst everything else gets changed,belts etc the cam chain slipper gets overlooked. Hope you find out its not that, all the best Andy

 

[944 man]

Its more likely to be the chain on an S; especially one thats had a regular belt change. At the very least itll need a number of valves and possibly all of them. At the other end of the spectrum itll need a new head and camshafts too. Its common for the chain to wrap around the web which carries the tensioner and rip it out, when it fails. Accepted wisdom is that this cant be repaired, although Ive heard differently recently. Valves are very expensive from dealers, but you can use valves from other vehicles which are identical, which are available for a fraction of the price (&lt;£10 rather than&gt;£70each!).

 

[Black Beauty]

ORIGINAL: tref . I guess the easiest way of doing that is to remove the tell-tale bung from the top of the cam belt housing and confirm there isn't a belt in there.

This post has made me concerned about the status of my cam belt, so i had a look last night in the Haynes manual to see if I could locate said bung, but couldn't. Embaressing as it is to ask, but where should I be looking to locate this bung! Top, bottom, Ta muchly BB

 

[zcacogp]

ORIGINAL: 944 man ... you can use valves from other vehicles which are identical, which are available for a fraction of the price (&lt;£10 rather than&gt;£70each!).

Oooh, that's interesting. Does the same go for the S2, and if so, what other cars will provide valves which work? And do they work as well as the Porsche ones, or is something compromised somewhere? Oli.

 

[944 man]

The S2 and the 968 have exactly the same Achilles heel; but they suffer less due to having more torque and tending to have their necks wrung less as a result. I honestly dont know which vehicles the valves come from, but Im confident that theyll perform in the same manner. Simon

 

[944 man]

I slightly misunderstood there, didnt I? I believe that the same applies to all models which use the similar head.

 

[zcacogp]

Not really .... you answered the question .... Where did you find out about the alternative valves? Oli.

 

[millimeep]

We haven't entirely made our minds up yet, but at the moment I'm planning to hire a car so I can get back to the 944 to take the valve cover and cam cover off so I can see what's been going on. A quick look through the workshop manual PDFs seems to indicate using lots of dial gauges to set the cam timing up, which is worrying me a bit, plus of course there's the special tools for belt tension as well. I have done cam belts on other cars, the last being a Citroen BX diesel, which although very awkard as space was limited by the inner wing, was pretty simple compared to what this looks like! So far, it's looking like we could spend a lot of time &amp; money, and still not get very far, plus everything is complicated by the 944 being 60 miles away... Unfortunately our best option could be to stick it on eBay and hope someone wants a project...

 

[944 man]

Itll be worth next to nowt that way, unfortunately. There are always more cars requiring them, than there are engines available.

 

[elvis]

Cam belt replacement isn't too bad in itself (dial gauges are £15 from machine mart and it's not rocket science if you follow the manual), tensioning tools can be borrowed from the club (and I never used one anyway, but that's probably not to be recommended). I changed the head on the drive with no real space issues (although make sure you follow the manual to the letter removing the cams [link=http://www.porscheclubgbforum.com/tm.asp?m=361615&mpage=1&key=&#361615]to make sure you don't do this[/link]..) Priority has to be working out if the belt/chain are still there. Belt is under the plastic covers at the front, you can get a fairly good view pretty quickly and the cam cover is easily removed with an allen key, this will allow you to get a look at the chain. If the belt and chain look OK then it's compression tests and so on. As per 944man, I hate to be the voice of doom but think you'll be lucky to sell a 180k 944 with a possible snapped cam belt, let alone get anything worthwhile for it...

 

[millimeep]

Thanks for the encouragement Elvis, looks like I'll be investing in some dial gauges, as we've decided to bite the bullet and fix it! We're going up for a recce on Sunday the 17th which will just be popping the cam belt cover and the rocker cover and having a look [:-] Then we'll organise getting it back, and getting stuck in. [8|] I've done cam belts before, so I'm not completely green, I'm sure with a bit of time and care it should be ok Just looked at your other thread []... I'll pay extra attention!

 

[millimeep]

Ok, been up to see our stricken 944S which is 60 miles away. We hired a Smart car from SixT as it was very cheap, they are interesting to drive as the seating position is very high so you're looking down on all the other traffic, so it doesn't feel small once you're inside. It also has a semi auto gearbox (the auto setting is awful, the upchanges are slow when you do them manually). It shifts back down to 1st when you stop, and this one had an Eco thingy which stops the engine when you're stationary with your foot on the brake, restarting when you let go (and it's smart enough to deal with hill starts like this too!). As it's total capacity is about the same as a single 944 cylinder, it ran out of oomph on the motorway. Anyway, back on topic, I started by looking in the inspection hole (Black Beauty - the bung is right on top of the cambelt housing, and doubles up as a clip for a sensor cable), and the belt was still visible, which due to the size of the hole seems to be the limit of checking anything this way. Next up was looking inside the distributor cap (mainly because I haven't taken it off before so I wasn't sure what I could see behind it - the answer was not much!). But I did find that the rotor and cap were badly worn, so we've got new ones on the way now. Then the rocker cover was next up, and to my relief, the chain looks good...

A quick check on the starter showed that the cams weren't moving (yes, I know this is not a good idea, but we've already cranked it over quite a bit before we really realised what was going on, so any damage will have been done). Next up was removing the air filter for clearance, which leaves a fairly generous space to look at the belts, closely followed by removing the belt cover, and my inital diagnosis was pretty close...

So, we've just bought some new belts and a cap and rotor arm, and we'll be up there soon and refitting them, and seeing if there's any further problems...

 

[zcacogp]

OK ... I hope for your sake that the new belt gets it going again. What's your approach going to be? Fit new belt and see what happens? I guess that, if this doesn't do the necessary, you haven't lost anything - you can then decide whether to remove the head where it is or whether to have it towed elsewhere for the work. Oli.

 

[tref]

Place your bets here... I reckon that on replacing the belt it will run, but lack power, and maybe rattle a bit depending on whether or not any of the valves stick open (in which case they will be firmly knocked shut again when the piston comes up to meet them). I think Oli is right though, there is the price of a belt to loose, and everything to gain... I have heard of cars with bent valves straightening themselves with use... not sure about 944s. I have seen and heard what a bent valve looks like, but... all the tales of woe I have come across have been with the eight valve engines... not sure how badly affected the 16valve ones are. Check something silly like the water pump or one of the idler rollers hasn't seized to cause the teeth to be removed from the old belt, then with a new belt on, a compression test will tell you the maximum or minium number of valves you may get away with replacing/lapping, depending upon how lucky you are.

 

[944 man]

If it needs valves its not the end of the world at under £10 each (£70+ from Porsche mind).

 

[elvis]

Good luck. Slightly confused as to how you only managed to strip a few teeth off as the belt wraps round each pulley by several teeth but you were right in your diagnosis. Check water pump, idlers etc but the water pump is driven by the smooth side of the belt so it won't be that that's damaged the teeth.

 

[tref]

If you look at the part currently over the water pump pulley, that has several teeth missing in a line... my guess would be that was around the crank at the time, everything else stopped, the crankshaft kept turning...