Timing Belt and Non-Interference Engines

[JayKayEm]

Hello All,

I have just sold my 944S2 and am looking for something else.

One of my major bugbears with the 944 was the d*mn timing belt and cam to cam chain that would make me wake up in the middle of the night in a cold sweat! Either that or I would pay a specialist 1k to get chains/belts/idlers/water pump all done. It seems to be the exact same set-up as the 928S4 - except doubled []!

I have always fancied a 928 but have ruled them out for the above reason.

I'm a good mechanic and regularily do cambelts on 'bread and butter stuff '- but the S4 engine does not fill me with enthusiasm!

However, I have heard - albeit 'via the internet' - so not really trusted - that 1984 and earlier 928's have a non-interference engine - so if the belt goes snap, there is a really good chance of no valve/piston contact. Is this so, and does anyone know specific models or engine ranges this applies to? Obviously it excludes the S4, but what about the others; 928, 928S or S2?

Thanks, Best Regards, and hopefully in a land shark soon []

James.

 

[Paul Fraser]

The 4.5 litre 928 and 928S models (till '84) IIRC. If I were you, I'd join the mailing list at 928.org.uk and have a look at the FAQ on the site.

 

[rd944]

i thought all 928's were interference ? course i may well be wrong on that.. maybe some low compression versions with dished pistons ? unsure ..

non turbo 924's are all non interference.. they are several leagues below anything else in terms of sophistication and performance though.

 

[sawood12]

I don't understand the issue regarding the timing belt on the S2? If you stick religiously to the replacement interval then you should have pretty much zero risk of failure. Also the chain and tensioner, granted may need replacement now, but once replaced should be good for another 100k miles / 15 - 20yrs. Idlers don't need replacement with every belt replacement (probably last a good four or more belt replacements) - nor does the water pump (every other belt replacement if you're super paranoid) so I don't see what the issue is? Is it cost? inconvenience? All high compression ratio engines will be an interference engine.

 

[pauljmcnulty]

Oi - I was going to say that!

944 belts are 48k/4 years. That'd be risking pushing it, so let's say 36K/3 years. The S2 has the additional chain and plastic thingy, so check them every belt change. Factor in, at the very worst, new cams on an otherwise cheap S2 because the sprockets have worn away. That'll cost a lot less than a 928! [&:]

In my five years of 944 ownership I have heard of a few 16v engines going bang. Every single one had a belt change well overdue. I never get it? Say it costs £400, and you need it every 4 years. Work out the saving between stretching that to 5 years and risking an engine, or playing safe and going for 3 years. It's a tank of fuel either way? Even if you need a new engine, it's not going to be too far away in cost from the bodywork attention that many cars are now needing.

My own opinion is that belts are a necessary consumable, like tyres. Sure, you can get cheap tyres - but would you really want to be driving a 928 on economy Taiwanese rubber? Same thing with belts, get them done by a specialist every few years and forget about them.

 

[JayKayEm]

Totally agree with all that. I took trips to JZ Machtech numerous times with the 944's I have owned.

Let me just clarfiy something. I'm not some muppet that is asking about interference engines because I want to run a timing belt to its death. I'm asking because if there is a choice of interference/non-interferecnce engines, it may sway a model choice, that's all. In addition, with my next toy/hobby/week-end car, I don't want to rely on a specialist for engine timing purposes anymore - I want to do it myself. Just like I do it myself on all my other 'normal' cars.

With no 944 balance shaft belt (that had a funny tension setting that justified specialist skills) I would be prepared to 'take on' a non-S4 timing belt replacement myself - but have never done a timing belt on a V-engine before, so I would be a bit nervous.
Working on my cars is part of the enjoyment. I just resent paying a speiclaist for something I should be doing myself dependant on the size of your balls.

I have a personal phobia of timing belts. Don't shout at me for this. I just have. Some people don't like heights. Some people don't like spiders. I don't like timing belts. End of.

I have a few cars on my shortlist - Mercedes W129 SL, a BMW 635CSi Highline or 928. Being a huge Porsche fan, I want to stick with. Problem is, I would not think twice about taking the head off an SL or 635 (both I believe are chain) - but as soon as you talk timing belts, especially on a V-engine, a shiver goes up my spine.

So, is it true that some early 928 engines are safe?

Or, any comments are welcome that 928, 928S and 928S2 cambelts regardless of model year are childsplay to replace and I should just get stuck in?

Ta muchly.

 

[sawood12]

OK, James, was just asking, didn't mean to imply any slight on your knowledge, skills or understanding. There are so many myths around 944's that simply are not true and the completely and utterly unfounded reputation the 944 seem to have for a weak timing belt is one. Just wanted to make sure you weren't going to sell your car on the strength of a false reputation. But if you simply have an aversion then fair enough, I can understand that.

Though, just for the record, I would just say one thing; I, like you, have always replaced timing belts on previous cars myself - all interference engines - and though i've haven't replced a timing belt on my 944 (left it to my specialist as I wanted the stamps in the book) from what I could tell the procedure didn't seem any more or less complicated than on any other car i've worked on. The balance shaft belt is an added element but not particularly any more onerous. And my specialist charged me £380 for my timing belt change which is about £300 cheaper than Ford want for a Focus timing belt change - so not bad value in my bood. Granted, it was just a timing and balance shaft belt change. I didn't replace my idlers or water pump.

Anyway - no bad vibes intended. Good luck with your 928 search.

 

[pauljmcnulty]

Anyway - no bad vibes intended. Good luck with your 928 search.

Seconded - I know the feeling. When my hanbrake shoes kept detaching it was simple enough to get fixed with new springs, third time around, but I almost sold the car over it. Having been stranded in several bad locations it got to the point where I was always listening for a "clonk" from the rear wheels, and that sort of paranoia takes the fun out of the car. [&o]