Timing belt question

[kensmith]

I have a 1978 Spider and have never owned a car that had a timing belt VS timing chain. How do you know when your timing belt needs replacing and if not replaced, what can happen when it breaks? Are they hard to replace? And when replacing them are there other associated parts that should be replaced at the same time? Thanks

[bobplyler]

If you don''t know how old it is, you should replace it. I replace mine every 30000 miles. On some engines, the valves can hit the piston, which can cause some serious damage. If the cover around the crankshaft is still in position, you will need to pull the front pully off to get this cover off. Most people discard this cover. I didn't pull the cover off the first time I replaced the belt, I cut the cover enough so that I could get the belt off (that was in 1979). It's not too hard to do, just make sure that you keep the pulleys aligned. You may want to replace the tensioner bearing at the same time.

[kensmith]

Can you see cracks or anything visible in order to tell if it's old and needs replacing? I have no idea when mine was replaced as I have not had the car long.

[RoyBatty]

Hey Ken,
I will be replacing mine along with the water pump and idler pulley in the next week or two on a Saturday.
If you want to watch the process, let me know.
I also plan to replace the head gasket in the process.
I will have my friend Sergio over to assist as he has much more experience in these matters with the Italian cars.
We plan to drink some beer as we tinker with my Spider.

[mdrburchette]

You can see the belt without pulling the cover, but you may not be able to see if the teeth are worn. If you don't know the age of the belt you should go ahead and replace it. It's not hard, even a girl can do it. In fact, I'll be doing at least one in the next couple of weeks. When you order parts, go ahead and get a tensioner bearing. It may seems fine, but sometimes they fail once the belt is slackened and retightened. You will also need to get a water tee gasket, since it need to come off to remove the cover. It would also be a good idea to check your water pump while you're at it, although I wasn't too happy with the last water pump I bought for my x19. It had a plastic impeller.

[azruss]

THIS IS IMPORTANT:
The idler pulley does not have any timing marks on it and the book is pretty vague on its rotation. before you remove the belt, rotate to TDC and mark the location of the idler pulley. location isnt as critical as the cam pulleys, but it is isnt in the sweet spot, it will hit the crank. The hole in the pulley should be located between the 1 and 2 o'clock position.

[bradartigue]

THIS IS IMPORTANT:
The idler pulley does not have any timing marks on it and the book is pretty vague on its rotation. before you remove the belt, rotate to TDC and mark the location of the idler pulley. location isnt as critical as the cam pulleys, but it is isnt in the sweet spot, it will hit the crank. The hole in the pulley should be located between the 1 and 2 o'clock position.

You align the bolt, the little hole, and the tensioner bolt, which, yep, puts it at 1 or 2 o'clock.

In terms of wear indicators the belts are fiberglass reinforced rubber. The lettering on the belts will be pretty faded by 20k and virtually gone by 30k, this is a pretty good indicator. Of course most cars won't be driven that many miles again in their entire life, so plan on a swap every 5 years or so just to be safe.

As others have said, if you don't know the age, change it out and the tensioner bearing. Also a good time to do the cam wheel seals and set the valve clearances.

[majicwrench]

Brad and I are gonna agree on this one.
Look at flat side of belt, if you can still clearly see the lettering belt is probably OK.
But, when in doubt, change it out.