Head replacement and timing belt .... (m20 2.5)

[GDBN]

Hi guys .... just put the head back on the old girl and then came the timing belt ...... when both cam and crank are at tdc there isn't enough slack to get the belt over the tensioner ... so having fiddled with it many times I always get the cam one tooth away from tdc. this ok or am I doing something wrong ? And when I was cleaning the cylinders out i turned the crank over to get to the bottom of the pistons....don't know how many times tho and I read the crank turns twice to one turn of the cam ....any way of checking if I need to turn the crank once to match the cam ?? Can you check by looking at the position of the piston in relation to the inlet valve ??? (inlet manifold not on yet )
Quick replies would be much appreciated ......

G

[Adammcf]

Hi
I had the same trouble getting my belt to fit. I spent about an hour. In the end I just the took the tensioner off and had a look, couldnt see anything wrong so put it on and tightened the spring as tight as it could go. The belt then slipped on and no more!

If you look at the crank where the pulley screws onto, there is a little mark. This should line up with a little notch on the lower belt cover when the engine is at TDC.
Below is a pic of my engine. You can see the little mark on the crank and cover as I marked them both with white paint.


The crank should turn 2 times for every 1 turn of the cam as far as I can remember. When at TDC the pistons will look like this:



Hope that helps!

[GDBN]

Thanks for that, Adam.
Pistons were exactly the same as the bottom picture so I'm glad that's right.
But the damn belt ..... put it on the crank first , tight past the the aux wheel and over the cam ..... fine - but then there's no slack by the tensioner -happened every time ... got the belt on - turned crank round twice - damn cam is off by one tooth ... took belt off ... moved cam and put belt back on this time by gently taking off the tensioner and fitting it on again .... back to one tooth out
Am I missing something ???

[Adammcf]

I turned the crank a tiny amount one way to make sure the belt was really tight against the cam when I looped it around it and then turned it slightly the other way to help slide it over the tensioner. Luckily when I did a few turns of the crank after the notches still lined up.

[Brianmoooore]

If you always end up with the belt one tooth out, then deliberately put it on with the belt one tooth out in the other direction. Tension it up, turn the crank over a couple of times, in the right direction, tension it again, and check the timing marks line up.

[GDBN]

Thx mate ....I'll try again in the morning ...but i think i tried that way too !! I will do that way again before releasing the tensioner and see what happens . Now trying to work out why the down pipes don't want to get reaquainted with the manfold !!!
Thx again ....
Giles

[Turbo-Brown]

I had this trouble.

I ended up taking the top bolt and spring assembly off so the tensioner could move miles to the left. Then put the timing belt on making sure it was properly alligned.

Next, push the spring into the tensioner and keep pushing untill it pops into the detent in the water pump.

Install the belt.

Rotate engine anticlockwise turning the cam pulley so that the tensioner side goes slack and gets tensioned by the spring.

Reinstall the bolt.

Drive off into the sunset

[GDBN]

First time I tried this morning it slipped on no probs ... lines up nicely now. thanks for the help... another question tho' ... when you put the inlet manifold on ...is there a bolt that goes into the head on the bottom row ?? I have a hole left without a stud and no nut left over .... what goes in there ??

[Martinaston]

As long as the belt is not directional you just turn it around the other way and it lines up.