Idle problem finally solved & a cam belt question

Looks like I have finally solved my idle problem. I managed to pick up a 1600 block with rebuilt head for ?50, took the cam out of it which looks stock and compared it to the one in my car, massive difference see below. I have been battling for months to work out what was wrong, previous owners don't you just love em  :roll:

Stock cam (i think)


Cam that was in my car


Anyway I have swapped the cam now and I am not 100% sure about the belt tension, I was very careful when I took the cam out, engine was at TDC and I marked the belt, I have made sure all the timing marks line up and pushed the tensioner as tight as it will go before tightening the nut. The trouble i have is that this is only tighening the one side and the other side of the belt looks too loose (see pics) it does only twist about 90 degrees  though.





Question is does this look ok and how are you supposed to adjust the tensioner, the one in the Haynes manual shows a 27mm nut for a spanner as well as the slackener nut ???

BTW, my engine is the original 1979 EG series 1.6 GTI

Any help much appreciated, I am dying to get it back together and see if it finally runs right.

Cheers
Kev

There was a change-over some time back from the hex adjustment method to the pin spanner, so your tensioner is the newer style. If you don't have the tool then get an olf fork and bend the required teeth to make your own, it works in a pinch. The most repair manuals and VW say the tension on the long section of the belt should be so that you can just turn it 90? with your fingers. Rhat does not really say much due to different people having different strenght. I went to VW many years ago and asked for a better discription and was told to do this: Tighten the tensioner until you hear it whine, like a turbo, then back off until it stops.

Old cam seems to be a race version and from the looks of it a worn out cam also. It is not normal to have sharp edges between the lobe and the side of the lobe. Might want to check the shims for wear too.

Many thanks Grimyfingers for the advice, old fork it is then.

All the shims were changed while I was troubleshooting (didn't know the cam was incorrect at that point) not only was the cam wrong the gaps were also miles out.

Tensioner is on the wrong way round! The pins should be towards the inner area of the belt, not the outer, so that the tensioner makes the belt curl more round the cam gear and then its easy to tension.

You've got the method for checking the tension of the belt about right, though.

the way i do it is fit my socket/spanner to the nut, then fit an allen key into one of the pin holes. brace the allen key up to the spanner/socket and push, tensioner spins, easy

it should be spun clockwise when setting the tension, you'll soon know its wrong as the tensioner will fowl the inner belt cover!

you can get the proper tensioning tool from gsf for about a tenner

Cheers everyone for the replies, I used the fork method which worked a treat, also finished puting it all together and its all fixed, my car actually runs as it should for the first time since I bought it  

Lesson is I guess don't ever take it for granted that the correct part has been fitted previously.