Darned timing belt tension

[CactusJack]

Hi all

Having a bit of trouble with the good ole (hm better said new) timing belt. I've tried to tension it (it's the manual tensioner) but i'm not sure if it is to tight or not. It's the first time i've done a timing belt....

Here are some photos

https://www.dropbox.com/s/0na2jfji50auylx/belt01.jpg?dl=0
https://www.dropbox.com/s/xymiwg5idh1ty1h/tensioner02.jpg?dl=0]

Thanks in advance for all your help!

[Phaeton]

I have the same question as I've just done mine, but to me that looks too slack, I wouldn't have thought you should be able to twist the belt like that. Does it hold it you manually turn the engine?

[CactusJack]

Hm I've turned the engine over by hand for 5 or 6 times. The Hayness manual says 4 times for a new belt, 2 times for a refit of the old one. After I've turned it over for 5-6 times by hand, I've cranked it with the coil pack disconnected. I'd rather the pistons hit the valves at 200 rpm than 1100 or so. Then I've started the car run for a few minutes and turned it off. Seems the tension is the same. But i'm not sure if it is correct. Some say that the tension is correct if the belt is to be twisted by no more than 90° on the midway between crankshaft and camshaft pulley. The correct way would be to have the SEEM C.TRONIC 105 tool. But since it costs me actually more than acquiring a new engine I had taken the risk :D.

[Healey]

It will probably be OK like that. I guessed my timing belt last time and this time before changing, I checked it with my Gates STT-1 and it was fine.

New belts have some pre tension in them so it will lose a little bit of tension after the engine has been run upto working temperature for some time.

[CactusJack]

Thanks mate!

Yepp I'll re-check the tension after the engine has run for some time again. I'd take it for a spin, but car has no MOT and I don't really have that yard to drive it.

About the STT-1, does it measure in SEEM units ? If not how do you know when it is properly tensioned ? I guess it might help if you try it on a known good tension belt and then compare it newly instaled one :D

[Healey]

The STT-1 is a Gates sonic belt tension tester, It checks tension by sound rather like tuning a guitar string. It does not show any measurement figures. It has 5 LED's 2 for under tension, 1 for OK and 2 for over tension. It knows what the tension should be from the part number of the belt as it has a database on a ROM inside the device. Unless you work in the trade it wouldn't be worth your while buying one as they are not cheap.

If you bought one of the Micrometer style ones you could probably measure the tension of a known good belt and then set yours to the same setting. I bought one many years ago but, there was no information about settings for specific applications.

Whereabouts are you cactusJack? If you were local I might check it for you.

[welshpug]

tension sounds perfect, if it flaps, it's too loose, if it whines, its too tigjt.

[CactusJack]

Hi Healey

Croatia, Zagreb. Guess i'm not a local ? :D

Anyway I run the car for some time now, and doesn't whine, doesn't flap, so I guess it should be fine now.

Thanks for answers and help :y:

[joshtd]

a timing belt of whatever kind should only be able to be twisted by hand 90 degrees. If it twists more or looks worn its time too replace it as well as if its new and twists more it reqires tightening the first picture to me looks perfect jack

[CactusJack]

Thanks a lot mate :)