timing belt questions

**sonic** · 09-04-2008,03:43 PM

greetings

why is it important to know the direction of rotation for timing belts?
if the belt doesn't have direction of rotation markings then what can be done?
is it possible for the cam and crank shaft to turn when trying to take cam belt off?

**Lofty79** · 09-04-2008,03:47 PM

cam and crank shaft need to be marked or locked or both. if belt has direction arrows follow em if not make sure as you stand facing engine that writing is up the correct wat when looking down on it.

**sonic** · 09-04-2008,04:00 PM

rotating the crank to align with tdc mark is quite simple.finding locking vag tools for crank and cam shafts is difficult. the car is a vw polo se 96.
is the rotation clockwise?

**sonic** · 09-04-2008,04:10 PM

...make sure as you stand facing engine that writing is up the correct wat when looking down on it.

you mean the writing on the belt should not be back to front?

example

vw polo

olop wv

**Lofty79** · 09-04-2008,04:32 PM

hehe thats correct. and start car and watch auxiliary belts for rotation direction

**vwmatt** · 10-04-2008,09:30 PM

If you are refitting the old timming belt, then it HAS to go back on the way it came off. If it is a new belt, then it doesnt matter which way it goes on.
If you imagine, the crankshaft and cam shaft push / pull on one side of the teeth of the belt so they wear more on one side of the teeth than the other, therefore go slightly out of shape. If the 2nd hand belt is put on reverse, it will wear both sides, therefore weakening the belt, and making it subject to slipping!! And you dont want that!

**sonic** · 10-04-2008,09:44 PM

how would you take the old belt off?
would you start from the cAm? is it alright to use a flat end screw driver to slide belt off the cam?

**vwmatt** · 10-04-2008,09:58 PM

If your going to put the old belt back on, then align the markings up, and once the tensioner is released, the belt should come off by hand. Dont use a metal tool !!!
If your going to fit a new belt, set up the markings, then cut the old belt off!
And yes, start the removal at the cam end, and that shouldbe the last bit you put on as well.
VW say the cam part should be fitted first.
But in reality last is easyer and better! m

**sonic** · 07-07-2008,03:05 PM

greetings

i changed the tensioner, timing belt and auxilatry belt.the car is running better than before. 2 problems, i think i tightened the tensioner bolt more than 20 nm.the tensioner alignment arrow is positioned in middle of v notch and belt tension seems accurate.the pointer DEFLECTS and goes back between v shaped notch or between v. shall i tighten the tensioner nut to 20 nm?
problem 2 is i hear a slight whizzing sound when accelerating.the sound seems to come from auxilary belt tensioner pulley.or is it t belt tension pulley?

**vwmatt** · 07-07-2008,06:18 PM

Originally Posted by sonic

greetings

i changed the tensioner, timing belt and auxilatry belt.the car is running better than before. 2 problems, i think i tightened the tensioner bolt more than 20 nm.the tensioner alignment arrow is positioned in middle of v notch and belt tension seems accurate.the pointer DEFLECTS and goes back between v shaped notch or between v. shall i tighten the tensioner nut to 20 nm?
problem 2 is i hear a slight whizzing sound when accelerating.the sound seems to come from auxilary belt tensioner pulley.or is it t belt tension pulley?

Its probably the plastic cover touching the belt, try removing the cover and refitting, this can be done quite easyly without having to touch the mount.