Can you actually tell if you need a new timing belt by looking at it?
 

I know there is a way to do a timing belt check, but i don't know when it was changed last changed. So would checking it even do any good? I should probably just get it done don't you think?

Are you going to risk bent valves over a $15 part?

I have a similiar dillemma. I bought my 944 nearly a year ago, but its had a broken odometer for at least a year with the previous owner. While I am nearly certian it was rarely driven (the po had a 98' 911), I don't want to risk distroying the engine for a "15 dollar part."

Would the timing belt condition degrade even if the car is rarely (once a week, and only to get engine warm) driven, or not driven at all?

yes rubber is dries out and cracks over time... even if its not exposed to UV rays.

Yes, time is one of the big enemies of the timing belt, pun intended. The fabled "time capsule" car is a time bomb of seals, belts and hoses that are way past any rational intended service life. Most of the service interval recommendations on timing belts that I've seen are usually XX000miles OR X years. If you do your own work, this is a $70 job (timing and balance shaft belts). You might want to take the same path we did building race cars, when in doubt, throw it out.

No

I was told every 40,000 at first,but unless its a daily driver you will not reach that for a long time.Several porsche machanics told me every 5 years.I just changed mine it had 40,000 -looked perfect.after I changed it, I realized that the tensioner was all the way extended.With no adjustment left-- not good.I do track my car.I will stick to 5 years. ( this is only my experience)

No, no, no!

Exactly. I'd say a visual inspection is better than nothing but not as good as a retensioning, which is not as good as a replacement. If anything looks bad as part of a visual inspection, change it immediately.

Since by the time a belt visually LOOKS bad it's already compromised in terms of its strength I'd say a bad looking belt is a guarantee it's bad, but a good looking belt is not a guarantee it's good.

If you don't know when or how many miles...do it now. Belt,seals,rollers and waterpump. Do it yourself. $400 or so in parts. I did mine when I first bought it. Take your time(weekend). Great way to get to know your car and not that difficult with some patience and planning.

I second that Burma Shave...

How do you change the belt without changing the valve timing? My belt has about 4k miles and 9 months on it according to the PO, but he also said the last one broke prematurely. :eek:

Worn belts will have a glazed look.

Can you actually tell if you need a new timing belt by looking at it?

Yes -- if it has cracks, missing teeth, glazing, etc.

Can you tell if you DON'T need a new timing belt by looking at it?

No. Therein lies the rub.

Clarks garage has a how-to, with pics.

To answer your question, theres several spots through the whole system where they are lined up to certain reference points, and as long as it all stays there and is lined up in the same spots on re-assembly, the timing stays the same.

Yes you can check, even the manual states that while setting the TDC through the inspection hole, you check the condition of the belt (to me, this is silly since you have a very tiny hole to look through).

When replacing the older belt on my NA, the independent specialist was an expert on 944's, he told me that the belt needed to be replaced even though he didn't take it off (yes, by looking at it).

When he took off the old belt and layed it over the new belt, the new belt was thicker (much thicker)........

Guess it comes down with experience..........but checking for missing teeth and cracks are the general way of "seeing" if the belt needs to be replaced.

I like to think I can tell, but to be honest, nobody really can. There can be hidden cracks, rotting etc. They can be a lot worse than they look, and they can be a lot better than they look. It's pretty much impossible to tell.
Best rule has already been said. I'd change the belts and rollers. For a first-timer, it won't take that long. Belts and rollers are around $120 from Zims.

and again No.

Visual inspection is fine for a KNOWN GOOD belt as a check. I have seen belts that look perfectly fine (even under duress and bending) that are bad when tensioning.. at full tension they may LOOK ok..You never know. better safe than really sorry.

Andy has a nice memorial building of bad belts (maybe 7) look good visually but are ready to give up the ghost AND valves...

Time and mileage on belts should be heavily respected.

I'm with Chris, these belts are deceptive. I like how the manual states, "Inspect and replace if necessary" without telling us what we're looking for. There's been a tonne of people here with unexpected belt-failures, regardless of mileage or age. I'd have to say, when in doubt, replace it...

I'm thinking if the belt is in several pieces, you need a new one.