Found this :~
https://www.volvoclub.org.uk/faq/Eng...TimingBeltTips
I did wonder what the large rubber bung was for in the belt cover-now I know and makes the task a lot easier (1988 240)

Timing Belt Tensioner and Belt Adjustment After Installation.
Replace the Tensioner? [Don Foster] A new tensioner every 150k is the prevailing wisdom as I understand it. No need for a new spring -- reuse the existing spring. You'll note a small hole in the shaft inside the spring. Compress the spring with old tensioner and slide a nail through the hole. Remove the tensioner and install the new one. Then pinch up with a big pair of Channelocks and remove the nail. And at 225k miles, start thinking about the three front seals and water pump -- perfect time to do all that stuff.
[Inquiry:] Whilst removing the tensioner, it flew apart. How do I reassemble it?
[Nigel Sheerwater] Tensioner consists of.....a bar with a big hole one end..pin hole the other. .....a spring...a bearing with a plate on the back and a big hole in the middle and a smaller hole at right angles. Assemble as follows. Put spring on bar. Slide the small hole in the bearing plate on top of the bar to compress the spring....tricky so you will have to work out how to compress spring. Once compressed put a nail through small hole to hold it all together. Torque to 50 Nm (37 ft-lb). [John Wilt] After installing the tensioner, you can move the belt by rotating the crank but only in a clockwise direction.
Adjusting the Tensioner After Installing a New Belt. [Stoney] I just got email from 2 dealer techs I know, with 18 and 20 years experience between them both are top VISTA techs and they said that the belt should be adjusted after 5-600 miles due to the fact that a new belt will stretch some in the first 1000 miles and they have seen a few jump the cam gear..
[Response 2: Don Foster] The tensioner has a spring in it which forces the idler against the belt to a predefined tension. But then, when you tighten the nut on the tensioner, you lock its position. The instant the belt stretches one hair, the tension is relaxed (because the tensioner's position is fixed, it can't move inward to maintain the force). The tensioner, in this configuration, compensates for (adjusts for) the increased length from stretching -- to prevent it from jumping a tooth. It DOES NOT maintain a constant force on the belt. It's assumed a new belt will relax a bit during when first used, so you must loosen the nut, allowing the spring to again reposition the idler. This consumes the extra length from stretching -- but then you tighten the nut again, locking the idler's position. Ideally, there will be virtually NO tension on the belt, but also virtually NO slop in the belt. Hence, after about 500 miles, more or less, remove the rubber plug from the timing belt cover, loosen the tensioner locknut, rock the crank slightly clockwise about 1/8 turn (this makes sure that belt has tension on the drive side between cam and crank gears), and tighten and retorque the locknut. [Editor] Make sure you lock that tensioner nut to prevent the tensioner from loosening and destroying the new belt. Torque to 50 Nm (37 ft-lb).

I now have my later 240 manual (ISBN 1850104026, 1991), and a 740/760 manual (ISBN1850105405, 1993) to hand; by this time the Haynes manuals are stating that re-tensioning should be done after 600 miles. Re-tensioning should be done with the engine at normal operational temperature.

That was a good piece Bob, well done finding it.

I see it contains yet another view on re-torqueing the cam belt idler (turning it 1/8 turn) - but no mention of starting (or ending) at TDC.

What should be conclude: that there are lots of opinions out there :-)

Alan

Oh I missed the 1/8 turn.

Thank you for that very true post ... lots of opinions are always with us ... let us rejoice in that. :)

Comrade Stephen Edwin



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I am reminded of a Rowan & Martin’s Laugh-In ending, spoken by Wolfgang.



Very interesting. And very true.



R.I.P. Arte Johnson.



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Just made this adjustment as the post recommends:~
Couple of points, I removed in part the timing case top cover- three bolts & one top screw.
The cover can be lightly pulled away without distorting or removing any other parts.
I wanted to see what was happening once the nut is released plus the belt condition- it did require some adjustment but the tensioner was quite stubborn to move over enabling the play to be taken up etc.

A light tap with a socket extension bar allowed the spring to do its job of pushing the tensioner over.
The large rubber grommet had been removed for a socket/ratchet rather than a spanner.
Quite straight forward and not a long job.
Trust it helps.
Bob.
('88 240 estate- 2.0L)

I thank David for alerting me to the Haynes he refers. I have obtained the 1982 - 1986 version. ISBN 1 85010 258 9
Cover is black with VOLVO in yellow.




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My cover is grey but it could be sunfaded.............

What about the cover of your book? ..... :)



My personal cover is faded grey.





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That is not a bad idea at all Bob. When I re-tensioned my cam belt I didn't do that, I just removed the large grommet, I was slightly uneasy that the tensioner had been released and done its job and there was no way of checking. Once I re-started the motor the belt was noticeably quieter though, so it must have been too tight or too loose and the adjuster did its job.
Alan