How old is yr timing belt

Purfler · Postby **Purfler** » Mon Sep 22, 2014 11:59 am

FWIW I can tell you what happens to a Celica when one of the idler bearings for the cam belt gives up... (Classic case of penny wise...)

Decades ago we had a couple of Fiat 1283Ps - (beautiful little things to drive, but rusted while you looked at them). The belt had to changd at 30K I think. I once used a non-genuine, but Italian, belt. Only once...

Tim

gslender · Postby **gslender** » Mon Sep 22, 2014 12:53 pm

Purfler wrote:FWIW I can tell you what happens to a Celica when one of the idler bearings for the cam belt gives up... (Classic case of penny wise...)

That's a really good point. If you follow the Mazda advice you'd only do the cam belt every 100,000 klms. Most uneducated mechanical types (like Mr M) would be thinking they're doing the very best to keep the car reliable, safe and being a good boy following the Mazda guideline.

After how many klms do you replace the idler pulleys? The Mazda workshop manual makes no recommendation on when to do this? Same with the water pump. This and other parts aren't specified and both can have as equally damaging result to the engine.

Some will say that, when replacing the cam belt, they'd also replace the idler pulley, water pump and everything else whilst "down there" but should you also replace the key way and crank pulley? Both are well known to wear and eventual failure. None of those are in any workshop guide!? A worn key way can damage the crank. Where is that in Mazda's schedule maintenance?

Mazda may be seen as "all knowing" with regards to the owners manual and workshop manual stating regular replacement of the timing belt - but fact is, we know Mazda made critical mistakes in the B6 engine used in the NA6 MX5. They got the cooling wrong (and was changed in subsequent models again and again) and the crank nose wrong big time (and most either replace the key way and crank pulley on a regular basis to ensure trouble-free maintenance).

No absolutely correct answer exists, but facts do remain - replacement of the timing belt is only necessary when it breaks. It may cause damage if it snaps, but potentially no more damage than a worn timing idler pulley, key way or even a simple fuel pump....

If you decide to replace the timing belt every 100,000 you may wish to consider doing a lot, lot more after your 3rd timing belt - or, just let it run until it breaks and save the $$$ and replace a bunch of things altogether.

Don't be a Mr M and just follow the workshop manual maintenance schedule - try to keep your head out of you @$$ or you'll be visiting the mechanic far more often than you'd imagine.

gslender · Postby **gslender** » Mon Sep 22, 2014 1:10 pm

Purfler wrote:Decades ago we had a couple of Fiat 1283Ps - (beautiful little things to drive, but rusted while you looked at them). The belt had to changd at 30K I think. I once used a non-genuine, but Italian, belt. Only once...

Oh, and the Fiat 128 3P has an interference engine. Replacing the cam belts is advised because if the belt snaps or jumps a tooth, it absolutely WILL damage valves.

Purfler · Postby **Purfler** » Mon Sep 22, 2014 1:29 pm

Oh, and the Fiat 128 3P has an interference engine. Replacing the cam belts is advised because if the belt snaps or jumps a tooth, it absolutely WILL damage valves.

It did

Tim

Ps - The Fiat was interesting in many ways. There were many things that needed replacing far more often than we would now - decades of engineering devlopment I guess. CV boots didn't last long at all - I could do one in 15 minutes towards the end. There was also the drive for the oil pump which also turned the rotor in the dizzie (remember them?). I think that was also a 30K km change. I always though that was really clever, if it failed you had no spark so the thing stopped.

hejira · Postby **hejira** » Sat Sep 27, 2014 10:04 am

Whats the typical cost (parts & labor) for a timing belt replacement on an NB1?

gslender · Postby **gslender** » Sat Sep 27, 2014 10:53 am

Various. Just the belt and if you did it yourself $150 and about 4 hours. Mazda parts and dealer could be closer to $1000

Mr Morlock · Postby **Mr Morlock** » Sat Sep 27, 2014 11:43 am

Don't do it yourself unless you have the time, the requisite knowledge, the space or cannot afford to pay a professional. Any competent mechanic can do the job and you will find much better pricing than $1000 including water pump. Just get a few quotes and that will become obvious- most dealers have high overheads so they tend to be more expensive than smaller businesses.