timing belts

[Guest]

Afternoon all, please excuse me if this has been asked before... I' m a new member, I bought my beautiful balck on black 951 about a month ago (from David Earl, who I' m sure some of you know) anyway... the belts were replaced about 8K and 4 years ago... I' m sure there' s a recommended time as well as mileage limit, but 4yrs would surely be a bit premature? also, am i right in thinking that the 951 is a non-interference engine? thanks - any advice greatfully received.
I' ve done about 1200miles since I bought the car - still can' t get the smile of my face!
photo to follow

 

[John Sims]

Matt,

Welcome to the joys of 951 ownership (There is a train of thought that suggests that the right hand drive 944 Turbo is a 952 but I' m still not sure myself.)

Although again not certain, I am of the understanding that camb belt breakage on any 944 is potentialy terminal, so I would think the potential for the valves and pistons to meet is reasonably high. Thinking latteraly, the 944 has a huge displacement for a 4 cylinder engine and a relatively short stroke, I can' t see how that would leave much room for an erant valve if it did go out of sync.

4 years is about the limit for a camb belt, some even change them every year but that might be a bit of an overkill. If you consider that the belt will degrade with age, most cars have a 48k belt change cycle. If average milage is 12K (as in 12K or one year service) then the belt should be changed at least every 4 years.

Personaly, I' d get all the belts replaced. An additional concern is that if in the four years, oil has contaminated the belt it' s life expectancy will be reduced.

If you have no reference to water pump replacement, and the car is in the 100k area, I' d have that replaced as well. It will only cost a little more than the purchase cost of the water pump to do it at the time - but big money if done through necessity by its self.

Happy Turboing

 

[bert gear]

I would agree with all John has said

 

[Diver944]

Hi Matt, good choice of car [] I look foward to seeing the pics. The official time from Porsche is every 48k miles or 4 years, whichever comes soonest. My personal limit is 36k miles or 3 years

However that was when the cars were brand new and all the rollers, pulleys and tensioners were in perfect condition. I have heard of several belt failures on various forums and it always costs big time, so preventative maintenance would seem prudent. Changing both belts by a recognised Porsche Specialist will be under £300 including the vat. If needed, a water pump at the same time would increase the parts cost by about £150

I bought my Turbo with only 15k since the last belt change, but it was 5 years previous. I had them both replaced the next day. For long life they should be retensioned after the first 2k miles as they will stretch in use.

Where in the country are you? Maybe someone can recommend a good and trusted Specialist near to you

 

[Guest]

Thank you all for your advice, I' ll now be getting belts done at the annual service in August.
I live in Vauxhall, London, about 1/2mile from RGA, and they have already had some business - new CV joints. Bob seems very nice and knowledgeable (and convenient!) Does anyone else use them?
I searched long and hard for my 944 and bought on the strength of the meticulous enthusiasm of the owner and a 3inch deep folder of bills - largely from La Rose, which was very reassuring and really helps when putting together a ' maintenance plan' .
After how many miles should I expect to replace a water pump? The car' s done 125K and has obviously had one replacement already, though I' ll have to check exactly when that was.
My previous car was a toyota MR2 turbo, that was fun but...

 

[tim court]

On the S2 dont forget those old favourites - the cam chain/tensioner - as well as belts. The belt driven cam drives the second cam via a tensioned chain running round toothed cogs.

My 89 S2 lost a tooth on the driven cam and (praise be the Lord and all his mercy) luckily the chain stayed intact.

All I suffered was a slight loss of power - no loud noises, no other symptoms - when I stopped and listened it sounded a bit clattery but nothing alarming, so I drove v carefully to my independant (Camtune) and they had a quick look inside.

Took off the cam cover and at first could see no problems. A magnetic feeler was shoved in a few orifices and we all recoiled in horror as it was withdrawn with a tooth on the end!!! When the chain was taken off the true extent of damage to the chain and cams became clear. So lucky not to lose the complete top end. The loss of power had been caused by the chain jumping a complete tooth so putting the valve timing out. Lucky not enough to clout the pistons. (Understatement of the Year Award 2001)

Although the chain, according to the history, had been replaced at 84,000 miles (the mileage was 120k) both cams were severely worn in the teeth department. Two cams, new chains and tensioner and a major extraction operation on my wallet saw the problems resolved. Thank god the engine was ok.

Belts? Oh they had been replaced at her annual service a month earlier.

 

[Guest]

Comparing the price of new belts to the price of a new engine, I'd be inclined to change them as a precaution.

I've been told that 36k miles or 3 years is a good interval between belts. My car had a new belt 35,000 miles before it had one snap.

 

[Guest]

i do mine every 12-15k miles (or annually around this time of year). I think the factory interval is around 30k miles, but I figure for the sake of £30 and a couple of hours work, It's be better than a £1k rebuild if it goes snap.

remember the retension after 2-3k miles too. It's VERY IMPORTANT!!!!!!

 

[Guest]

Isn't the retension supposed to be after 1000 miles?

 

[944Turbo]

I thought it was 1k miles as well, or 2K km I ran my belts to 48k as factory reccomendation but had a good look at them at 36k. Not sure when the auto spring tensioner was added, if I had a pre auto adjust car I would change them sooner. I would certainly have a good look at them at 4 years old as well, make sure there was no wear, contamination or tiny cracks.
when changing belts its worth checking the water pump, if its original its time for a new one. Also consider replacing rollers every 2 belt changes. If one siezes its bye bye belts even if they are new.
Tony

 

[sawood12]

Wow, every 15k miles seems a bit excessive. with a 40k mile limit, although I would never exceed, surely taking it upto 35k should be perfectly fine(?). What are the origins of the time limit?

In any case i've decided to get the belt replaced ASAP along with the water pump, balance shaft belts and rollers. I believe the front engine seals are not too tricky to replace as well so they might as well get replaced while they are at it. Seems far more economical to blitz these things now while they have the front of the engine exposed.

 

[Guest]

I realize 15k is a bit anal, but I've seen what happens when that belt goes, and it's not a pretty sight (not on my engine thank god). Peter Sanden in Sweden showed me one that had let go. It munched the head pretty good, bent the valves, put holes in the pistons, actually took a chunk out of the cylinder wall (with all the debris flying i suppose), imploded a couple of followers and twisted one so that it wedged itself in the cam housing. That engine was junk! [] Supposedly it was extreme, and I've heard on rennlist that a couple of people have got away with no damage at all, but I really really don't want to take that risk.

I beleieve the limit was part of the original spec from Porsche, so they will have blown something up at 50k to see what happens back in the '80s, and then reccomended a lower change interval!

Waterpump is a good idea if it's not been done before. and so is replacing the rollers. they can get quickly worn in the bearings with belt dust flying around. You're right on the seals too, they are relatively easy when all those gubbins are out. I take it you'll chuck it at a specialist for all this, right? (too bloomin cold to DIY it at the moment! [:'(] )

 

[sawood12]

It's in there now. He took a look at the timing belt which wasn't in too bad nick visually (not that that means anything) but, to use his exact words "the balance shaft belt was hanging on by a thread". So it looks like I got there just in time as i've heard that the balance shaft belt can sometimes take out the timing belt. Actually it all makes sense as i'm sure he guy I bought it off said he reaplced the timing belt but not the balance shaft belts at around 94k which might explaing why the timing belt was in much much better nick than the balance shaft belt which was replaced at 80k miles.

I decided against going for the cylinder head gasket but the specialist is going to take a good look at everything. He reckons the engine seals are in good nick so has recommended that I don't replace at this point. I suppose if i'm going to be changing the belt at 15 to 20k mile intervals from now on then they can wait.

So close escape then!!!

 

[Guest]

Checking the invoices of my S2, the previous owner serviced the car at around 90,000 miles, and the balance belt had already snapped (it said 'investigate rough running engine' I think!). Both belts were replaced then (and retensioned later), and at least it proves that a dead balance belt isn't necessarily going to kill your engine, but better safe than sorry. Now I just need my timing chain replaced...

Tom

 

[sawood12]

I was worried that the balance belt flapping about might take out my timing belt. Anyway all done and dusted now so I can sleep easy for the next 15 to 20K. Rest of the car checked out fine as well so I'm pretty happy if not alot poorer after a major service and a coolant and brake fluid change. Oh well it's down the pound shop for Christmas pressies this year!!

 

[Hilux]

People also forget that in a cars early years it is driven a lot so the timescale that the mileage is accrued in is a lot shorter.

Do not think that cos you dont do many miles you dont need to change the timing belt etc cos you are wrong.

Manufacturers state a time scale also as belts age with time or lack of use.

 

[944Turbo]

I have done 15k since March in mine [] (despite being out of the country for 2 months with it parked) Fair point about the belts ageing though.
Tony

 

[Dan944t]

Hi Phil ,

last set of belts and rollers that I bought and fitted to my 87 turbo was I believe continentals ( they were bought from Andy at Promax )

In all honesty I havnt converted from manual tensioner to spring loaded, but I have got the experience of both as I also have a non turbo 944 1986 lux which has the adjustab tensioner, and have done the belts on both a couple of times, and all I can say is I much prefere the spring loaded self tensioner as I have had a belt snap on the non turbo when I was 18 and it's always plagued me since, and so when I first did the belts on my turbo I a good feeling of reassurance in knowing the spring was giving the tension ( although you always need to check for tension after maybe 500 miles I think it is just to be sure things don't loosen up )

be sure to change all the rollers whilst doing your belts as one of my rolkers was the cause of my belt snapping where it wasn't spinning anymore where it dried up from the heat of the engine.

You live and learn as they say ?? That cost me thousands believe it or not!

all the best
Daniel

 

[Waylander]

Gates Are OEM, the belts you buy from Porsche are made by Gates

most come from the factory in Scotland.

I have this info from a man who works for Gates, even though i have Conti belts on my 968, i would add that from my experience Conti tend to whine a lot more

 

[blade7]

I bought my last set of belts and rollers from Promax, I think they may have been Contis. I worked for Gates for 14 years and I'd have no hesitation using either. IMO though, the tensioning procedure takes no account of the head/block expansion that puts more tension on the belt, and prematurely wears the waterpump bearing.