timing belt tension

[zacc]

hi i have an NM 3.5 and would like to know how tight the timing belt should be . i have tried doing it to the specs but to me the belt seemed way to tight , on either side of the crank shaft sprocket you could flick the belt and it would twang . now when i took the old oneoff there wasa fair bit of slack . so what iwoul d like to know what sort of deflection should the belt have once installed and is the new belt directional when out of the box or i does not matter? thanx

[zacc]

come on guys someone must know

[psproule]

Looking at the service manual, there is no specification given for belt deflection. But there is a lot of information on checking the belt tensioner operation and torque settings for such. Do you have the workshop manual?

Pat

[zacc]

yes i do .i need to know how much deflection there should be as i am getting a noise coming from it. now i have tried a bit loose, tight, and it is still there . all bearings are new , tried it without the serpintine belt. it sounds like a bearing but cannot be . it is a dayco belt .

[dolphin]

did you replace the adjust spring and bearing that should be replaced when fitting a new timing belt ?

[zacc]

it does not have a spring , it is hydraulic tensioner . yes it has been replaced

[Para Ordnance]

Noisy water pump?

With the second adjustable tensioner, you only need a tiny bit of force on it, less than 5 Nm from memory. Most people don't even touch it.

Have you applied too much force on it?

[6G74]

God knows for deflection, have never payed enough attention. What i can tell you though, it doesnt matter which way the belt goes, and for the instances where it does, there will always be directional arrows (which it wont have). As for the tension, i get the belt tight enough that when i pull the pin on the tensioner it barely moves if at all - if your unsure though, dont do it so tight and let the tensioner take up the slake?? im talking so it only just moves though.