Cam belts

[AndyG]

A old question regarding cam belts on a 620, I have one, start it every 10-20 days but used very little , had belts changed two years ago and covered approx 2K since then. I have read its not wear than damages then but lack of use. Question, is it really neccasery to change then now, I had had the covers off and they look perfect and are tensioned the same as when fitted two years ago. Has anybody has belts break after 2 years ?.

Who's good in the midlands for changing belts ?
Thanks

[Catspoon]

The thing you have to remember with belts on any machine is that they will degrade over time, used or not. Now the recommended change interval does sometimes allow for some forgetfulness/abuse on the part of an owner, but it doesn't do to take the mickey. It's just too risky.

Having said that, I know of cases of the belts on Rover 75s, which had a recommended change of 95k / 6 years being done at 130k - well over their limit, which does show that you don't necessarily have to panic, just get them done sooner rather than later.

I'll PM you someone who could help out with changing the belts by the way.

[Nickj]

I had a belt break on an old SS, literally went in a clean line right across the belt itself. The rest of the belt look sparkly clean and the same as a new one but not so continuous.
Couse no springs in the head to speak of means the cams keep spinning so the piston can go say hello to the valves. It trashed the front head and piston.

The problem with unused belts is the drive round two fairly small toothed pulleys, so they flex quite a bit as then run. Thats what wears them out.

Being as the belts are so quick and easy to change it's really not worth taking the chance with them. Honestly the hardest part is getting the covers off!!

[big john]

http://www.youtube.com/watch?v=9vzPZ84ZRjU&feature=PlayList&p=A570042B2F0F8230&index=0&playnext=1
The above link has possibly been posted before, but is very helpful.
I used it when i changed a 620 set of belts. It`s well worth doing it yourself as it`s quite easy and saves alot of money.

[Nickj]

If you're at all worried about 'something moving' when changing belts (nothing will honest) you can add a simple safety net.
Once everything is lined up mark the scribed/punched lines on the pulleys with a dab of paint or nail varnish. mark the same points on the old belts.
On the new belt make a first mark mark then add a second one the same number of teeth away.
Check the indicator marks are lined up or just close then stick the new belts on so the dabs all line up. Now it's exactly as it was before but with new belts. Crank up the tension and off you go.

The vid is very good, shows just how quick a job it really is

[Nickj]

On the original question

Who's good in the midlands for changing belts ?

You are !! ;)

[AndyG]

Thanks for all the info, looks like I may well have a go myself

[Rockhopper]

The engine will tend to stop in the same postion after each time its run, if you take the belts off you will find that have "set" into the same position that they are in on the engine (this is a bad thing as you get tight and slack parts of the belt as it goes round).

[Catspoon]

Just a follow up question as I decided this evening to look at doing the job myself.

Is there a recommended torque setting for the tensioner bolts, and which side of Hercules levels of strength is it? A cursory fiddle with an allen key revealed a gorilla must have last done them, so a set of bits is coming over tomorrow from younger brother's to get my wellybar on to deal with them.

[Catspoon]

....great, got them all loose after a lot of effort, swearing and slowly slacking them off except one which is rounding out. Cosmic.

Would using an impact drive on it damage the casing? Just thought I'd ask before Mr Blunt instrument comes out to play.

[Pedro]

I've had a thread round off and had to drill the head of the bolt off. You could try an impact driver but do soak the bolt well forst in a decent penetrating fluid like Plus Gas. (WD40 won't do the job)

[Catspoon]

Thanks Pedro. After an overnight soak with penetrating oil a friend popped round today for some moral support and expert advice, and between us we got it out intact. Didn't actually do much damage to the fixing, and after some judicious refiling and general monkeying around with the bolthead, for the moment it's still perfectly usable to the correct torque setting. I think I might get shot of the fixings used in the rollers anyway for some stainless alternatives. Oi likes me fixings to be proper hard, me!

Did the oil and filter while I was at it (the stuff was black), so the bike is now pretty much ready for a long warm dry summer. Fingers crossed!