Any Advice, Part 2!

[Stephen Edwin]

Different instruction in : Bentley re 240 1983 through 1993.
I'll try to post a note sometime as to what Bentley says.

Overall I'm seeing points I haven't remembered. [Some] specify engine at running temperature to retension.

I might manage to post a note some time. EAOE

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[Bugjam1999]

Interesting- although since the book doesn’t specifically say not to re-tension the belt periodically after that first 600 mile interval, and I have seen posts on forums here and elsewhere concerning timing belts skipping teeth, I’ll stick to periodically retensioning mine. Of course you could say quite reasonably that if a belt is loose enough to skip teeth then it should have been replaced already, which I wouldn’t disagree with.

Cheers

[Laird Scooby]

Originally Posted by Bugjam1999

Interesting- although since the book doesn’t specifically say not to re-tension the belt periodically after that first 600 mile interval, and I have seen posts on forums here and elsewhere concerning timing belts skipping teeth, I’ll stick to periodically retensioning mine. Of course you could say quite reasonably that if a belt is loose enough to skip teeth then it should have been replaced already, which I wouldn’t disagree with.

Cheers

If it's loose enough to skip teeth it isn't tensioned correctly and probably wasn't retensioned after 600 miles. Also constant retensioning (i.e. more than one retension during its life) will over-tension the belt which can result in stripping teeth - same end result, the car stops!

If it was necessary to periodically retension, it would say so in the service schedule. I've not seen it in any Volvo service schedules.

[Othen]

Originally Posted by Bugjam1999

Interesting- although since the book doesn’t specifically say not to re-tension the belt periodically after that first 600 mile interval, and I have seen posts on forums here and elsewhere concerning timing belts skipping teeth, I’ll stick to periodically retensioning mine. Of course you could say quite reasonably that if a belt is loose enough to skip teeth then it should have been replaced already, which I wouldn’t disagree with.

Cheers

Ah, now I remember, you had mentioned re-tensioning the cam belt at service intervals previously, that is why I'd suggested it to Chris.

I must admit, I still can't think of any reason not to re-tension a cam belt at service intervals and so make sure it is always running the way Mr Volvo intended it to. On bikes (almost exclusively chain drive cams) re-tensioning is almost always a service job (usually a similar arrangement with a spring loaded idler).

Maybe Dave will know why it should only be done once?

Alan

[Othen]

Originally Posted by Laird Scooby

If it's loose enough to skip teeth it isn't tensioned correctly and probably wasn't retensioned after 600 miles. Also constant retensioning (i.e. more than one retension during its life) will over-tension the belt which can result in stripping teeth - same end result, the car stops!

If it was necessary to periodically retension, it would say so in the service schedule. I've not seen it in any Volvo service schedules.

Spooky - you have answered my question above in the time it took me to write it!

I can't agree that a spring loaded idler can ever over-tension the belt, so that can't possibly be the reason. I'm still struggling to think of a reason why re-tensioning the belt say every 10,000 miles would not be a good idea.

I agree that the service schedule would say if it was a requirement, but it certainly doesn't say not to do it, and it omits some other things such as carrying out the re-tensioning at TBC on #1 (well, it does omit it in my 240 book, but not in your 740 book).

Alan

[Bob Meadows]

I'm a bit lost on this one:~

I thought that once the belt has been renewed and the tensioner released then that is it? i.e. the tensioner automatically adjust itself being spring loaded.

Should I get my coat ready!
Bob.

[Laird Scooby]

Originally Posted by Othen

Spooky - you have answered my question above in the time it took me to write it!

I can't agree that a spring loaded idler can ever over-tension the belt, so that can't possibly be the reason. I'm still struggling to think of a reason why re-tensioning the belt say every 10,000 miles would not be a good idea.

I agree that the service schedule would say if it was a requirement, but it certainly doesn't say not to do it, and it omits some other things such as carrying out the re-tensioning at TBC on #1 (well, it does omit it in my 240 book, but not in your 740 book).

Alan

Belts stretch and wear as they are used Alan, retensioning them leads to more stretch prematurely and also stresses the teeth on the belt so they can break off. That makes it a very bad idea to keep retensioning it!

For the cost of a belt, if in doubt - renew it!

Also i was referring to the Volvo service schedule, not the Haynes Book of Fantasy (HBoF) service schedule where things are omitted but also some useful things are inserted, for example changing the diff oil that Volvo don't bother to recommend.

Others have mentioned Autodata, i've found most of their books inaccurate at best and downright wrong at worst. As such, i take most of what is in Autodata as "use with caution" but double-check if at all possible with one or more other sources.

Also mentioned have been some books of USA origin, again to be used with caution! Very often the USA spec cars have different specs, schedules and so on compared to us - not just Volvo but many makes - so to use a USA book on a UK car or vice versa could cause major problems.

[Laird Scooby]

Originally Posted by Bob Meadows

I'm a bit lost on this one:~

I thought that once the belt has been renewed and the tensioner released then that is it? i.e. the tensioner automatically adjust itself being spring loaded.

Should I get my coat ready!
Bob.

No, the tensioner is then locked off again afterwards, it isn't a contantly adjusting type.

[Othen]

Originally Posted by Laird Scooby

Belts stretch and wear as they are used Alan, retensioning them leads to more stretch prematurely and also stresses the teeth on the belt so they can break off. That makes it a very bad idea to keep retensioning it!

I'm still not really with you on this one Dave: if a belt stretches surely it is better to re-tension it than to knowingly run it too loose. I just can't see that would be the best solution.

Alan

[Laird Scooby]

Originally Posted by Othen

I'm still not really with you on this one Dave: if a belt stretches surely it is better to re-tension it than to knowingly run it too loose. I just can't see that would be the best solution.

Alan

Thing is Alan, it's designed to stretch that much and when it's "knowingly slack", it's still tight enough. If it is retensioned then, it becomes too tight and overstretched, past its elastic limit.

Have a think about it, i know you'll work it out!