When to replace timing belt?

[nobbyfox]

Thanks Martin.
But I don't need to do this till next summer. Plenty of time!

[max and caddy]

Yeah..you're supposed to lock everything off....however and although my statement was a little tongue in cheek, if you marked everything with tipex (camshaft/pump/crankshaft pulley's) slipped the old belt off, the new belt on and everything was in exactly the same place! the job is done, simpulz.....it's just if anything had moved and you got it I tooth out (just make sure all the slack goes to the tensioner side)

Martin

Ahh..found you..thanks for keeping me and many other mechanics in business over the last few years. All that nonsense in the vw manuals is rubbish of course and tippex is a much better/quicker way to do this simple task...

[California Dreamin]

Ooooh dear, have I said someone wrong lol.

To my knowledge I did not say Tipex was a better/quicker way, perhaps you could point me to where I said that.

And yes I'm VAG factory trained, are you?

Forgive me for suggesting that, if someone took a great deal of care, double checked everything, and followed some strict rules, that it is entirely possible to safely change a belt WITHOUT locking tools.
As I said..as far as timing belts go, the simple 8 valve single overhead cam, single belt, single tensioner arrangement is as simple as it gets..
Perhaps I should have said, if you get this wrong you could seriously damage your engine but then of course, that applies whether or not you use locking tools.

Martin

[max and caddy]

Vag trained yep...so why is it the top pulley on a taper i ask?

[California Dreamin]

Strange this is, I'm usually the one urging caution with all things, so for someone to insinuate that I'm suggesting something reckless....I do understand.

Martin

[max and caddy]

Nope...like I say ta for keeping me busy...seen lots of diesels damaged due to tippexed belt changes...belts were not fitted a tooth out...can't of been as that would be terminal on start up.....but we're out of time causing valve piston contact...then...tappet failure..JX shim tappets are quite robust..hydro tappets lose the tops after xxxxx miles.

First mistake is assuming the timing is correct to start with...second is assuming the belt is the same pitch between the teeth...yes it should be...but it's rubber and moulded....normally I'm keen to take a short cut but having seen the consequences I get a bit emotional over these belts!

[California Dreamin]

A bit retrospective and in hind sight, if I was going to suggest this method again, I should state the very obvious and that is to set the engine to TDC so all of the factory marks could clearly be followed.
And may I say it's not helpful suggesting that I am personally responsible for keeping you busy. I like many others on here, go to great lengths to help people with their vans and I don't know about you but I'm only human.
Whilst I am only too happy to be corrected remember we are all here for the same reason, helping each other.

Martin

[max and caddy]

Ok..I apologise..just getting on my high horse! Problem is there are no marks other than TDC...locking bar and feelers for the cam, pump is not relavant to engine damage as such but needs a dti..

[dekhelia]

The above would be fine (relatively, anyway) for a petrol engine, where the timing is judged to be acceptable as long as valves are not striking pistons. With a compression-ignition motor things are not really that liberal: the tolerances involved are critical, especially if the engine is to run at peak efficiency. Which, after all, is kind of the point of having a diesel in the first place.

[Rogue Trooper]

Bro a competent mechanic

Are you Sure?

[AdrianC]

second (mistake) is assuming the belt is the same pitch between the teeth...yes it should be...but it's rubber and moulded...

I struggle to see how a belt can have a different pitch between teeth and actually work. The teeth positively locate in the teeth on the pulleys. If the pitch is different, they won't, the belt can't locate, and is very likely to jump.

If a particular belt's that badly made, then surely that would be obvious on the first manual turn-over of the engine? If it's not one tooth out, rotates over manually, and is correctly tensioned, how can it not be _right_?

[nobbyfox]

Bro a competent mechanic

Are you Sure?

Well ok, only slightly better than me then!!