I have a 85 740 turbo and I just did the timing belt as well as front seals. I checked if the lines and the marks on the sprocket was matched up before starting the car. It idled good for about 3 seconds and sounded terrible. So I took the top timing belt cover off and saw that it skipped two teeth back. I took everything apart and starting from beginning again but now I am noticing that the belt between the balance shaft sprocket and the crank boss is quite loose. Even when the lines are matched up. Any tips on how to fix this?

I am using a Contitech belt and INA tensioner. Both new of course. Also is it normal to tap the nub on the tensioner into the front of the head?

 

The tensioner is to take up the looseness of the belt, and is the only thing that moves as the other wheels are all fixed... "The nub", I think should be in the head, if I understand you correctly? (The tensioner gets installed LOCKED with a pin in place, after the belt is on, you release the tensioner to take up the slack).

Once you are done, before closing it up, rotate the whole thing by the crank bolt a couple of complete revolutions to see how it all meshes, and if the marks still stay in their places.

 

Yes I did all this and it doesn't all line up. When I have the markings on the belt lined up to all the markings on the sprocket and rotate them all they don't stay lined up. Also it is very hard to have tension between the balance shaft sprocket and the crank boss. Is there any trick to make this any easier?

 

wait, markings on the belt?? there's no significant markings on the belt. you line up the markings on the various sprockets per those diagrams, install the belt, release the tensioner, and if you turn the crank 2 full turns, all the marks should be lined up again (2 turns of the crank is one turn of the cam and intermediate shafts).

 

There are two single lines on the belt to be lined up with the overhead cam shaft sprocket TDC mark and intermediate shaft TDC mark. Also there is two lines that are to be lined up with the crank boss front shim TDC mark. Is this wrong?

 

those marks on the belt don't matter. what matters is the angle of the crank relative to the intermediate and camshaft.

 

you probably tighten the tension-er too much.....on my first Volvo I had, doing the timing belt, I over tightened the tension-er and literally ripped apart the belt...when I cranked it a few times.....so you over tightened the tension-er a little so it did not spin correctly and caused a skipped tooth.....

Please call it the "INTERMEDIATE SHAFT" and "Crank pullley"......I did read the crank boss on a manual from the 70's....NOT TO OFFEND...It just screws my brain.

 

http://www.stepbystepvolvo.com/Resou...ng%20belt1.pdf

Did I get the wrong information? I tried to follow this as close as possible. So if you don't go by the markings on the belt, how do you know how much belt tension should be between the sprockets?

When I line up the marks on the belt there is way too much tension between the overhead camshaft pulley to the crank pulley. Also not enough between the crank pulley and the intermediate shaft. I am very confused, maybe I got the wrong belt.

 

those marks on the belt will NOT line up again until it all goes around many turns (whatever the least common multiplier is of the number of teeth on the entire belt and the number of teeth on the cam shaft pulleys...)

 

As Pierce said, the timing marks on the belt are only good for initial alignment. They will not line up after you go through two rotations of the crank. Really, it's best to use the alignment marks on the rear timing belt cover for the cam and intermediate shafts.

When setting the tensioner, make sure all slack is taken up between the cam and intermediate shaft, also make sure the same between the intermediate shaft and crank. You can do this by slightly rotating the crank clockwise until the slack is taken up. Only then release the spring on the tensioner and then tighten the tensioner. Also, after running the car for 500 miles or so, the tensioner bolt should loosened, turn the crank clockwise a little and then the tensioner bolt re-tightened. This re-tensions the belt to account for any stretching that may occur. There is a plug in the timing belt cover that allows this re-tensioning without removing the cover.

 

Okay thanks guys for all your help and awesome Volvo info. This is my first Volvo, I have always wanted one but got distracted with other projects. I will ignore the marks on the belt and concentrate on the TDC marks on the pulleys. I will let you guys know how it goes. Wish me luck.

 

Okay so after two days of frustrating simple timing belt work, I have came to a conclusion the marks on the belt are correct and I am stupid. It must be the tensioner that is making it slip. When I line up the lines on the belt to the TDC marks on the pulleys, that is the tightest that belt can go. I tried and tried to make it tighter but that is it. So I turned the crank pulley twice and the TDC marks line up. I turned it twice more just to be sure and they line up again. But I noticed that the belt on the overhead cam pulley is slowly moving forward every rotation. It almost looked like the tensioner is pulling it forward every time I turn it. This must be why the belt is slipping. The weird thing is I have an INA tensioner and I thought this was OEM. Even though I bought it off eBay maybe Volvo made two different types of tensioners? I will be contacting my local Volvo dealership to confirm part numbers. So far I have found this on FCP's website. I don't want to purchase it since it could be the same one I bought off eBay.

Volvo Timing Belt Tensioner (940 740 760 780 240 242 244 245 745) INA (OEM) 463633OE | FCP Euro

Also I found this just now. I am so stupid I should have done more research. Apprently someone had the same problem and posted it on this same forum. DUHHH.

https://volvoforums.com/forum/volvo-...e-24079/page2/

 

So, why don't you try the old tensioner to see if it works better? If it works, then that's the problem... If it doesn't, something else is out alignment...

Also, so the belt creeps a little forward, but by how much? If it is right at the lip or even slightly hanging over i wouldn't worry too much. Give it a few rotations, even start the car and see what happens...

 

how can a toothed belt slip unless its really loose ? all the drive pulleys have cogs.

or, do you mean its riding up on the flange and not sitting happy in the middle? if that, then I'd be looking to see if the tensioner pulley is square.

 

The belt is creeping forward toward the edge of the pulley... not slipping around it...
Seen it happen, so may be it will just settle a little forward on the pulley and stay there, providing all else is right.