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Old 02-18-2019, 05:39 PM   #1
monty400k
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Default 960 3.0 24v timing belt issue

Started my car last week after it had been parked for a few hours on a steep slope, straight away it sounded terrible so it was quickly switched off, its a high mileage engine but had belts, tensioner and pump replaced 3 months ago so I was at a loss as to what could have wrong, thought maybe low oil and the angle it was sitting had starved it but when I rolled it onto the level the oil was sitting perfectly at the max mark on the dip stick. Towed it to the garage that did the work, initially they thought the tensioner has failed, the cams were in time with each other but the belt was 3 teeth out at the crank.

The engine was swapped out of a car I've owned for 6 years into current one which I bought with a duff engine back in Sept, the water pump went 3 weeks later so got the belts and tensioners at the same time, it has 280k on it but the head was rebuilt 3 years ago and was running perfectly

Update from the garage today, they retimed the engine and turned it by hand to check for interference then started it, it ran for 2 secs and cut out, it now has no compression so assuming the valves weren't bent before its safe to assume they are now. They haven't been able to shed any light in why it jumped 3 teeth on the belt in the first place or what happened today, good thing Ive got a spare head, looks like im going to need it...

Does anyone have any suggestions?
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Old 02-18-2019, 07:15 PM   #2
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Originally Posted by monty400k View Post
Started my car last week after it had been parked for a few hours on a steep slope, straight away it sounded terrible so it was quickly switched off, its a high mileage engine but had belts, tensioner and pump replaced 3 months ago so I was at a loss as to what could have wrong, thought maybe low oil and the angle it was sitting had starved it but when I rolled it onto the level the oil was sitting perfectly at the max mark on the dip stick. Towed it to the garage that did the work, initially they thought the tensioner has failed, the cams were in time with each other but the belt was 3 teeth out at the crank.

The engine was swapped out of a car I've owned for 6 years into current one which I bought with a duff engine back in Sept, the water pump went 3 weeks later so got the belts and tensioners at the same time, it has 280k on it but the head was rebuilt 3 years ago and was running perfectly

Update from the garage today, they retimed the engine and turned it by hand to check for interference then started it, it ran for 2 secs and cut out, it now has no compression so assuming the valves weren't bent before its safe to assume they are now. They haven't been able to shed any light in why it jumped 3 teeth on the belt in the first place or what happened today, good thing Ive got a spare head, looks like im going to need it...

Does anyone have any suggestions?
Any teeth missing from timing belt?
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Old 02-18-2019, 07:38 PM   #3
monty400k
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Will check tomorrow, heard of dowels snapping on redblocks which throws the timing out, I appreciate the white block is a totally different engine but could there be anything like that worth checking?
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Old 02-19-2019, 08:32 AM   #4
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Is it manual and was it parked rear downwards? There have been cases where manual car is parked rear downwards and next time belt skips 3-4 teeth on the crank. Have had to repair one 850 and one 960 because of this.

I've read and believe it's because handbrake has been applied after the car is resting against the gear. This again causes the engine to nudge backwards and belt presses the tensioner. Next time starting belt skips because there isn't a proper tension. Expect slightly bent valves.

Edit. Now that I think again 3 teeth on the crank might still be fine. Cutting off could be just a random event, but lifters in these are sometimes sensitive with shutting the engine off soon after starting. It just has to be cranked with good rpm or towed until it starts. And keep it running a minute or two to avoid doing the whole thing again.
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Old 02-19-2019, 11:46 AM   #5
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Is it manual and was it parked rear downwards? There have been cases where manual car is parked rear downwards and next time belt skips 3-4 teeth on the crank. Have had to repair one 850 and one 960 because of this.

I've read and believe it's because handbrake has been applied after the car is resting against the gear. This again causes the engine to nudge backwards and belt presses the tensioner. Next time starting belt skips because there isn't a proper tension. Expect slightly bent valves.

Edit. Now that I think again 3 teeth on the crank might still be fine. Cutting off could be just a random event, but lifters in these are sometimes sentitive with shutting the engine off soon after starting. It just has to be cranked with good rpm or towed until it starts. And keep it running a minute or two to avoid doing the whole thing again.
There are no manual 960 over here if he didn't do a manual swap by himself...
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Old 02-19-2019, 01:34 PM   #6
monty400k
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Quote:
Originally Posted by Lankku View Post
Is it manual and was it parked rear downwards? There have been cases where manual car is parked rear downwards and next time belt skips 3-4 teeth on the crank. Have had to repair one 850 and one 960 because of this.

I've read and believe it's because handbrake has been applied after the car is resting against the gear. This again causes the engine to nudge backwards and belt presses the tensioner. Next time starting belt skips because there isn't a proper tension. Expect slightly bent valves.

Edit. Now that I think again 3 teeth on the crank might still be fine. Cutting off could be just a random event, but lifters in these are sometimes sentitive with shutting the engine off soon after starting. It just has to be cranked with good rpm or towed until it starts. And keep it running a minute or two to avoid doing the whole thing again.
Im in the UK, it is a manual car with a 3.0 swapped in, the rear was parked downwards and the handbrake is terrible so it was left in gear. Went to the garage this morning, they have retimed it so all the marks line up correctly however piston one which should be at TDC is at the bottom of its stoke, it looks like the key on the crank has sheared off so the bottom pulley is not where it is supposed to be, hoping it's on the pulley and not the crank as I've got a spare one, otherwise it'll be time for another engine.
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Old 02-19-2019, 04:30 PM   #7
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None of the cylinders are at TDC when timing marks are aligned. All whiteblocks are the same.

If the pulley has moved that means that the nut hasn't been tightened properly(doesn't need to be opened for belt change). Pulley and crank have pretty tight spline. If the nut is even close to being tight there is no possibility to shear the spline off.

Looks like this when it shears, crank was fine:
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Old 02-19-2019, 05:07 PM   #8
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None of the cylinders are at TDC when timing marks are aligned. All whiteblocks are the same.

If the pulley has moved that means that the nut hasn't been tightened properly(doesn't need to be opened for belt change). Pulley and crank have pretty tight spline. If the nut is even close to being tight there is no possibility to shear the spline off.

Looks like this when it shears, crank was fine:
That's great news, will pass that on to the garage in the morning, hopefully just valves to get it back on the road, I've got a 2.5 with a 3.0 crank and t5 pistons ready to go after reading your thread on your 240!
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Old 02-20-2019, 02:23 PM   #9
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That's great news, will pass that on to the garage in the morning, hopefully just valves to get it back on the road, I've got a 2.5 with a 3.0 crank and t5 pistons ready to go after reading your thread on your 240!
I've had this exact failure (splines polished from the pulley). It is not common, but does happen, even if the bolt is tight.

It confused the heck out of my mechanic because the belt was fine, and his records showed the timing belt had at least another 15k miles before it needed changing.
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Old 02-20-2019, 02:45 PM   #10
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Update, garage removed the crank pulley and it was good as new, out of options they took the head off, all good there too, valves look to be fine, however when they try to wind the engine over on the crank there is several points of resistance so it looks like it has spun a shell so engine is scrap.

Ive got the 2.5 that came out of the car that could probably be refitted although it wasn't running that well when I got it, I suspect the head gasket, wish Id done a compression check before taking it out, Ive got a 2.8 low compression engine that Id set aside to turbo charge at some point although this would not be a quick solution. I could source another 3.0, either way its probably going to cost me more than Im willing to spend and I need transport so it looks like Ill cut my losses and break it
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Old 02-21-2019, 05:25 AM   #11
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I think they are trying to dig too deep and might be slightly surprised if there really is a spun bearing. A bearing won't make the timing jump and it won't stop the car from starting up or running unless it seizes.

Quote:
Originally Posted by jwernerny View Post
I've had this exact failure (splines polished from the pulley). It is not common, but does happen, even if the bolt is tight.

It confused the heck out of my mechanic because the belt was fine, and his records showed the timing belt had at least another 15k miles before it needed changing.
Still saying it hasn't been tight. I've done hundreds of belt changes to whiteblocks and diesels and stripped tens. They all have the same type pulley and only time I have seen a damaged spline is in the picture above.

Last edited by Lankku; 02-21-2019 at 05:33 AM..
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