My long running head gasket repair (see previous post - Cylinder Head Bolts) is nearing completion - it has been delayed by problems with my back, probably caused by it !
I started the car successfully yesterday, but had to stop it quickly because of a screaming timing belt. The idler tensioner pulley was not turning, so the belt was skidding over it causing all the noise.
I've followed the Haynes procedure, or so I thought, and tightened the pulley nut as near as I could guess to 40nm - its impossible to get a torque wrench on it. The tensioner itself is OK and spun freely with no noise off the car.
Can someone enlighten me how to get this right - both Haynes and Vadis gloss over how to do this with engine in car - they both assume you've got good access - anyone who has battled with this timing belt will know that access is limited and scraped knuckles are not an option.
I replaced the water pump at the same time, and the engine seems to run OK so I think I've got the timing right. The auxiliary belts are refitted ie air con and alternator belts, and not making a noise. The problem just seemd to be with the tensioner.
Anybody with experience of this ?
Timing belt tensioner 480 GT
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glasgowjim
- 480 Is my middle name
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Roland
- Started learning about 480
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- Joined: Sun Feb 15, 2009 7:55 pm
- Location: Halifax, England
Re: Timing belt tensioner 480 GT
Thanks Jim - I read this post beforehand, and used the long screwdriver method to tension the belt
"Get a strong and long screwdriver and use it as a lever on the rear side on the tensioner. Get the cambelt nice and tight (if you press on it it shouldn't move more than a few mm. Let your friend tighten the locknut full.
but tightening the locknut fully, as suggested, prevents the tensioner wheel from turning - hence the screaming from the belt. By backing the locknut off I can get the wheel to turn, but the locknut is then far from tight - certainly not 40nm.
I am confused
"Get a strong and long screwdriver and use it as a lever on the rear side on the tensioner. Get the cambelt nice and tight (if you press on it it shouldn't move more than a few mm. Let your friend tighten the locknut full.
but tightening the locknut fully, as suggested, prevents the tensioner wheel from turning - hence the screaming from the belt. By backing the locknut off I can get the wheel to turn, but the locknut is then far from tight - certainly not 40nm.
I am confused
Re: Timing belt tensioner 480 GT
At first glance at both the how-to and the posts I seem to be missing the trick to immobilize the crankshaft. This is done by inserting a 8mm lock pin after removing the plug at the bottom right beside the dipstick. After this tightening should not be a problem I presume. But I should admit this kind of job is carried out by my universal garage so I have no experience, forgive me if this is no help at all.
Too old to bother
480 Turbo midst '91
480 Turbo midst '91
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Roland
- Started learning about 480
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- Joined: Sun Feb 15, 2009 7:55 pm
- Location: Halifax, England
Re: Timing belt tensioner 480 GT
My saga with this belt rumbles on - a sprained wrist is now adding to my excuses 
The locking pin in the crankshaft Robou is not an issue - that simply holds the crankshaft stationary at it's TDC position with No 1 cylinder whilst the crankshaft pulley is off and the timing belt is being manipulated into position. Once the crank pulley is back on and the belt is in place, with camshaft and crankshaft properly aligned, then the locking pin is removed. The engine can then be turned, using a socket on the crankshaft pulley bolt, to double check the timing belt alignment.
The crankshaft locking pin is not there to enable the tensioner nut to be tightened.
My issue is that the tensioner pulley locks up when I tighten it's retaining nut - and I don't understand why.
Haynes talks about using a home made tool, consisting of a bolt attached to the end of a metal bar, which is inserted in the back bracket of the tensioner, and pressed downwards to tension the belt. When I tried this the bracket just moved south with no apparent effect on the tension.
I'm now wondering about that bracket and whether it should be/is properly attached to anything. Problem is - it's impossible to see what's going on with the belt in place, and I can't find a decent exploded diagram to explain it to me.
Any contributions gratefully received
The locking pin in the crankshaft Robou is not an issue - that simply holds the crankshaft stationary at it's TDC position with No 1 cylinder whilst the crankshaft pulley is off and the timing belt is being manipulated into position. Once the crank pulley is back on and the belt is in place, with camshaft and crankshaft properly aligned, then the locking pin is removed. The engine can then be turned, using a socket on the crankshaft pulley bolt, to double check the timing belt alignment.
The crankshaft locking pin is not there to enable the tensioner nut to be tightened.
My issue is that the tensioner pulley locks up when I tighten it's retaining nut - and I don't understand why.
Haynes talks about using a home made tool, consisting of a bolt attached to the end of a metal bar, which is inserted in the back bracket of the tensioner, and pressed downwards to tension the belt. When I tried this the bracket just moved south with no apparent effect on the tension.
I'm now wondering about that bracket and whether it should be/is properly attached to anything. Problem is - it's impossible to see what's going on with the belt in place, and I can't find a decent exploded diagram to explain it to me.
Any contributions gratefully received
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glasgowjim
- 480 Is my middle name
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- Joined: Sun Oct 01, 2006 5:28 pm
- Location: GLASGOW SCOTLAND
Re: Timing belt tensioner 480 GT
does this help ?
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Roland
- Started learning about 480
- Posts: 66
- Joined: Sun Feb 15, 2009 7:55 pm
- Location: Halifax, England
Re: Timing belt tensioner 480 GT
A good pic Jim and thanks for that.
I was immediately looking for the bracket on the back of the tensioner pulley, upper left, but doesn't seem to have one on yours - unless, and it's a horrible thought - it's behind the timing cover back plate.
If so - does that mean the tensioner pulley is fitted before the backplate ?
Can't imagine that, but if so than I'll have to go back to square one.
These subtle details are missing from any of the "how to's" that I've read and are precisely what a timing belt virgin like me needs
I was immediately looking for the bracket on the back of the tensioner pulley, upper left, but doesn't seem to have one on yours - unless, and it's a horrible thought - it's behind the timing cover back plate.
If so - does that mean the tensioner pulley is fitted before the backplate ?
Can't imagine that, but if so than I'll have to go back to square one.
These subtle details are missing from any of the "how to's" that I've read and are precisely what a timing belt virgin like me needs
Re: Timing belt tensioner 480 GT
Roland
The belt CAN be tightened with the rear cover in place!!
I just did mine a few weeks back.
nip the tensioner pulley 'just' until it stops it sliding towards rear of car with the 'residual' tension
jam a LONG screw driver/tyre lever between the LEFT edge of STEEL cover (or between the bolt that holds cover on TOP LEFT)and the tensioner pulley THEN tighten FULLY the NUT in centre of the tensioner pulley.
sorry my engine is in the car and can't provide any photos.
does your tensioner pulley free spin on when you have it on the bench? if NOT it sounds as if it is fouling on something?
try ths :
well I was going to put in an image but can't figure out how to? ? ? ? ?
I don't seem to have the 'upload attachment' tab that is on the SCIMWEB site (same software/hosting system)
Any hints and tips?
The belt CAN be tightened with the rear cover in place!!
I just did mine a few weeks back.
nip the tensioner pulley 'just' until it stops it sliding towards rear of car with the 'residual' tension
jam a LONG screw driver/tyre lever between the LEFT edge of STEEL cover (or between the bolt that holds cover on TOP LEFT)and the tensioner pulley THEN tighten FULLY the NUT in centre of the tensioner pulley.
sorry my engine is in the car and can't provide any photos.
does your tensioner pulley free spin on when you have it on the bench? if NOT it sounds as if it is fouling on something?
try ths :
well I was going to put in an image but can't figure out how to? ? ? ? ?
I don't seem to have the 'upload attachment' tab that is on the SCIMWEB site (same software/hosting system)
Any hints and tips?
Alan
480 ES 2litre 'Celebration' ? , C30 1.8ES, SS1
480 ES 2litre 'Celebration' ? , C30 1.8ES, SS1
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Roland
- Started learning about 480
- Posts: 66
- Joined: Sun Feb 15, 2009 7:55 pm
- Location: Halifax, England
Re: Timing belt tensioner 480 GT
Thanks Alan for this - you're right - the tensioner was fouling on something.
Last night whilst waiting for the Liverpool v West Brom match to start (how sad is that) I had another go at the tensioner. I got a pencil torch light down there so I could see better what was happening. It eventually dawned on me what the problem was.
There is a small locating stub on the engine block at the back of the tensioner which the RH end of the tensioner bracket slots onto. It's almost impossible to see this once the tensioner and belt are in place. It's also easy to dislodge the tensioner from it once fitted. The stub only protrudes sufficiently to fit flush with the bracket.
I used the screwdriver on the back of the pulley, as you suggest, but the bracket must have slipped off the locating stub as I put pressure on the screwdriver. When I fitted the locking nut and tightened it, the tensioner would not have been properly aligned. It's also the reason why using the Hayne's method (above) the bracket just moved south.
The trick I missed was in not nipping up the locking nut slightly before applying pressure on the screwdriver, so that the tensioner bracket could not move off the stub.
I feel a bit stupid
now for not realising this, but maybe this write up it will help some other poor innocent doing this job for the first time. The engine is ticking over nicely now with no untoward noises. Fingers crossed 
One other thought - it also occurs to me there must be different types of tensioner on these engines looking at the various ones for sale on e-bay and also Jim's pic above. The bracket lugs on my 2 litre, now correctly fitted, are at 11o'clock and 5 o'clock relative to the tensioner wheel. There is no bracket at all so far as I can see in Jim's pic above.
This must be a source of some confusion for anyone reading how-to's.
Last night whilst waiting for the Liverpool v West Brom match to start (how sad is that) I had another go at the tensioner. I got a pencil torch light down there so I could see better what was happening. It eventually dawned on me what the problem was.
There is a small locating stub on the engine block at the back of the tensioner which the RH end of the tensioner bracket slots onto. It's almost impossible to see this once the tensioner and belt are in place. It's also easy to dislodge the tensioner from it once fitted. The stub only protrudes sufficiently to fit flush with the bracket.
I used the screwdriver on the back of the pulley, as you suggest, but the bracket must have slipped off the locating stub as I put pressure on the screwdriver. When I fitted the locking nut and tightened it, the tensioner would not have been properly aligned. It's also the reason why using the Hayne's method (above) the bracket just moved south.
The trick I missed was in not nipping up the locking nut slightly before applying pressure on the screwdriver, so that the tensioner bracket could not move off the stub.
I feel a bit stupid
now for not realising this, but maybe this write up it will help some other poor innocent doing this job for the first time. The engine is ticking over nicely now with no untoward noises. Fingers crossed One other thought - it also occurs to me there must be different types of tensioner on these engines looking at the various ones for sale on e-bay and also Jim's pic above. The bracket lugs on my 2 litre, now correctly fitted, are at 11o'clock and 5 o'clock relative to the tensioner wheel. There is no bracket at all so far as I can see in Jim's pic above.
This must be a source of some confusion for anyone reading how-to's.