Help! First breakdown in 15 years

[Clifford Pope]

Originally Posted by chris s

You can probably tell from my previous post that I didn't retension the belt after I fitted a new one last time.

You have to release the bolt and compress the tensioner to get the new belt on surely? So you must have retensioned it?


Positioning a new belt is simple in theory but really fiddly in practice.

It starts when you loosen the nut and then compress the tensioner and stick a nail in the hole to keep it compressed. At that point you can either remove the nut completely and replace the tensioner, or spin it and check that it runs freely. (In my experience they last for ever, and can be lubricated by soaking in oil overnight and then drying very thoroughly before re-fitting.)
Refit the tensioner keeping the nail in place, and position the new belt on the marks. Tighten the nut up finger tight then release the nail to let the tensioner tighten the belt.
Re-check to see that the belt hasn't slipped on the marks, and that the belt is in the middle of the three pulley faces. Then tighten the nut properly.

You then need to wind the engine round at least 2 turns slowly using a ratchet screwdriver on the bottom pulley bolt, watching that the belt remains dead centre on each pulley and hasn't veered off to one side.
Loosen the nut a little to let the tensioner re-position itself, and tighten.

Points to watch - the tensioner must be absolutely flush against the engine, with no dirt. The belt must be absolutely straight, otherwise if it is angled it will wander over to one side. There is nothing to hold it in the middle position, but if it starts straight it will stay correct - hence test-winding slowly before starting up.

Reassemble and start up. After running for a few minutes I like to again release the nut half a turn and re-tighten, just in case of a bit of initial slackening. I repeat that after the first good run - say 50 miles.

Another tip - take great care removing and replacing the rubber plug. You really don't want to lose it inside the cover.

[Laird Scooby]

The term "non-interference" means the valves shouldn't contact the pistons in the evenet of timing belt failure.

Conversely, an interference engine does.

I'm surprised your head was badly corroded though, perhaps antifreeze changes have been delayed longer than 2 years each time?

[mrredwards]

Hi Thanks for your reply.You state that the vast majority of b200f head are none interference.What B200f head are interference head? I do know my way around classic car having restored Lots and lots over 40 years.Im just interested
what happened to my head.Regards Ron.

[Laird Scooby]

Originally Posted by Clifford Pope

After running for a few minutes I like to again release the nut half a turn and re-tighten, just in case of a bit of initial slackening. I repeat that after the first good run - say 50 miles.

Another tip - take great care removing and replacing the rubber plug. You really don't want to lose it inside the cover.

You're also meant to repeat the retensioning after 600 miles! Not just after 50 miles!

[mocambique-amazone]

I've just had a closer look to my notes and I did have a B200F with bent valves :-(
The car with this fault had a frozen bearing of the tensioner. You could hear this a few 1000miles in front of this!!!
Owner doesn't want to follow my instructions...
It did have a shaved head (forgot the amount of shaving, didn't measure I believe) and was with a VX3, the cam with most of lift in stock cams.

Maybe your ones are bent too, for bad luck.
Good luck, Kay

[Laird Scooby]

Originally Posted by mrredwards

Hi Thanks for your reply.You state that the vast majority of b200f head are none interference.What B200f head are interference head? I do know my way around classic car having restored Lots and lots over 40 years.Im just interested
what happened to my head.Regards Ron.

Seeing Kays post about a B200F head Ron, it's possible yours may have been skimmed to correct warpage from a previous head gasket failure (HGF) so if the head had perhaps been changed and had a higher lift cam (like Kays did) then it's probable that was the cause of your bent valves. Still unusual to bend all 8 as there are more times than not when there are less than 8 even partially open.

[Clifford Pope]

But the engine surely doesn't stop dead if the belt snaps - crankshaft and cam shaft will go on spinning, and obviously will slow down at different rates?

[Derek UK]

If the belt breaks the cam will stop turning straight away, certainly much quicker than the crank. B200 is interference and B230 isn't. B230 belt changes have been done at the side of the road. I've not heard of having to re tension the belt after 600 miles, that's what a tensioner does.

[Laird Scooby]

Originally Posted by Clifford Pope

But the engine surely doesn't stop dead if the belt snaps - crankshaft and cam shaft will go on spinning, and obviously will slow down at different rates?

The cam shaft WILL stop as there is nothing to drive it if the timing belt breaks. Whether the crank keeps turning is another matter, usually on a manual it is forced to so will damage the valves every time the pistons go up and down but on an auto, stops more or less instantly.
Don't forget the reason the valves get bent is because of vale to piston contact, it can in certain cases put holes in pistons because of being forced to contiue turning unless you put the clutch in rapidly.

Originally Posted by Derek UK

If the belt breaks the cam will stop turning straight away, certainly much quicker than the crank. B200 is interference and B230 isn't. B230 belt changes have been done at the side of the road. I've not heard of having to re tension the belt after 600 miles, that's what a tensioner does.

The tensioner isn't automatic!

It is a service requirement by Volvo that the belt is retensioned 600 miles later.

The tension has to be set manually once the tensioner locknut is slackend half a turn or so.
If you don't retension it, you run the risk of it becoming loose in service and stripping the teeth.

No teeth = no drive to the camshaft!

[chris s]

Another update chaps!
After replacing the cambelt and tensioner the car still wouldn't start. A compression test showed no compression, none!
I removed the head to find partiallly opened bent valves, so obviously this B200 ( I can't remember the suffix offhand) is an interference engine. Fortunately the pistons look in perfect condition and a check of the bores showed no bore wear.
What seemed like a stroke of luck was that for sale only 10 miles away from me was a reconditioned head complete with gasket set. It has the '530' marking on it, so I assumed it was the right one as it had been fitted to a late 80s B200.
Unfortunately, after purchasing the head, when I compared it to my existing one there are a number of differences, so it now looks as if I will rebuild the original head.
Do you experts out there recommend that I have it skimmed whilst it's off the car? Or would this be a waste of time on an engine which has never overheated in our 15 years of ownership?
Thanks,
Chris