Uno Slipping timing belt

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Uno Slipping timing belt

Carlit

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Hi I'm new here but I have a problem with my uno fait 1100 91 model my timing belt slipping motor still running...when rev up it jump one tooth... it's a new timing belt and tensioner....don't know any more...any one had a similar problem..tia
 
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Either the tensioner is not set correctly, allowing some slack in the belt, or the camshaft is taking more effort to turn than it should.
Is the oil supply to the camshaft getting there properly? Has the head gasket been changed recently, as these get put on upside down, and the oilway is then restricted.
 
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Carlit

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My car run well after I replace my timing belt a few days ago....by the 3 day it started doing that slipping..jumps a tooth and there is just one way you can tight the tensioner...timing belt still stiff....runs perfect when idling..just when I rev up my car switch off then it don't wanna start any more ...I bought a new tensioner as well still doing it
 
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Another thing I noticed is my water pump is noisy can that also be a reason
Always a good idea to replace the water pump with each belt change. This is standard practice in the UK. A noisy pump is evidence that the bearings are well worn, and could get tight at higher speeds.

Change the pump. Don't get one with a plastic impeller, as they can become loose on the shaft, insist on a metal impeller.
Also put a new belt on. It will have sustained damge each time it slips.
 
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Carlit

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Always a good idea to replace the water pump with each belt change. This is standard practice in the UK. A noisy pump is evidence that the bearings are well worn, and could get tight at higher speeds.

Change the pump. Don't get one with a plastic impeller, as they can become loose on the shaft, insist on a metal impeller.
Also put a new belt on. It will have sustained damge each time it slips.
Thanks I will do that
 
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From my recollections of having owned an Uno 70S (1985 to 1998) and Uno SX (1988 to 2001) the cam belt tensioner was not sprung loaded and required manual accurate manual tensioning. Fiat had a fancy lever arm with a sliding weight to set the correct tension. I never used this and "did it my way" but do recall that getting the belt tension correct was as such not difficult but DID require a little knowledge, attention to detail AND a revisit to check that everything had settled correctly.

I don't recall the water pump being driven by the cam belt and can not check my manuals as I'm moving house and these historic Fiat workshop manuals are now in storage.

Beyond incorrect tension then things that can cause belt slip are oil contamination and tight cam shaft operation.
 
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From my recollections of having owned an Uno 70S (1985 to 1998) and Uno SX (1988 to 2001) the cam belt tensioner was not sprung loaded and required manual accurate manual tensioning. Fiat had a fancy lever arm with a sliding weight to set the correct tension. I never used this and "did it my way" but do recall that getting the belt tension correct was as such not difficult but DID require a little knowledge, attention to detail AND a revisit to check that everything had settled correctly.

I don't recall the water pump being driven by the cam belt and can not check my manuals as I'm moving house and these historic Fiat workshop manuals are now in storage.

Beyond incorrect tension then things that can cause belt slip are oil contamination and tight cam shaft operation.
By '91, this should be a FIRE engine, so water pump is cambelt driven. I think if it was not cambelt driven, OP would not have mentioned it.

Would still be a good idea to remove the cam cover and check it is getting oil.
 
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Carlit

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Do you mean the cam shaft ?....and what I noticed yesterday is when I put timing in...my motor runs perfect but revs it up it don't wanna idle any more nore start...unless I put my feet on the gas a little it starts..and rev up but won't idle...secondly I turned my motor back on the timing marks it starts again perfect ....so that's what confusing to me I never loosen anything just turned it back on timing marks...
 
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Carlit

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Do you mean the cam shaft ?....and what I noticed yesterday is when I put timing in...my motor runs perfect but revs it up it don't wanna idle any more nore start...unless I put my feet on the gas a little it starts..and rev up but won't idle...secondly I turned my motor back on the timing marks it starts again perfect ....so that's what confusing to me I never loosen anything just turned it back on timing marks...
And yes it's a 91 uno fire have it for 8 years now
 
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Carlit

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This is how my cam shaft look like....what cause the blackish on the shaft ....is it a bad sign?
 

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As you have done, cam cover removed, to check there is oil at the camshaft.

That pic does not look good. The right side of the centre bearing appears to be lacking in oil, hence the apparent wear, and the black goo that suggests very old oil, which is breaking down. This looks like an engine that has not had its oil changed for a long time. The black goo is created as a result, and will clog oilways. The 'front' end of the camshaft (nearest the drive pulley/belt), what little we can see, looks better. It is likely that the oil supply is restricted, the spray bar across the top will need replacing, but the oil supply to the centre and rear camshaft bearings are likely to be suffering from inadequate oil supply. They are seizing, which is causing the belt to slip. If you continue, one or both will seize, and either the belt will strip, or it may break the camshaft.

Stop driving it.
Remove the camshaft and clean all the oilways. Repalce the spray bar. Check clean oil is pumped up through the main supply at the front, then can get along the oilways. Clean out as much of the black goo as possible.
If you are lucky, the cam bearings can be cleaned up and will work, might be a little noisier than before. Worst case, needs a new head, or engine.
 
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As you have done, cam cover removed, to check there is oil at the camshaft.

That pic does not look good. The right side of the centre bearing appears to be lacking in oil, hence the apparent wear, and the black goo that suggests very old oil, which is breaking down. This looks like an engine that has not had its oil changed for a long time. The black goo is created as a result, and will clog oilways. The 'front' end of the camshaft (nearest the drive pulley/belt), what little we can see, looks better. It is likely that the oil supply is restricted, the spray bar across the top will need replacing, but the oil supply to the centre and rear camshaft bearings are likely to be suffering from inadequate oil supply. They are seizing, which is causing the belt to slip. If you continue, one or both will seize, and either the belt will strip, or it may break the camshaft.

Stop driving it.
Remove the camshaft and clean all the oilways. Repalce the spray bar. Check clean oil is pumped up through the main supply at the front, then can get along the oilways. Clean out as much of the black goo as possible.
If you are lucky, the cam bearings can be cleaned up and will work, might be a little noisier than before. Worst case, needs a new head, or engine.
Yup, I agree PB. It's a pretty typical example of what the inside of an engine looks like when oil changes are neglected. I can only think to add, Carlit, DON'T BE TEMPTED TO TIP A CAN OF ENGINE FLUSH INTO IT! If you do what may well happen is that a lot of that hard gritty gunge will be dislodged and travel round the oilways to cause even further problems. So, If it was me I'd be taking the spark plugs out and spinning her over to see what oil supply to the lobes is like. If oil is being supplied from at least some of the holes in the wee pipe, then I'd be removing the timing belt and cam bearing hold down bolts and then the camshaft itself. Now you can see the oil supply holes to the cam journals. At this age of engine it's going to be non interference, isn't it? So crank the engine over on the starter and watch to see what the oil supply is doing at the cam journals. If supply seems good check the cam lobe dimensions - they look a bit like there could be wear on the tips? Then clean up the carbon deposits on the cam and reassemble with a new oil pipe. If there is any question of serious wear or lack of oil supply to the journals the head will need to come off and be properly cleaned/exchanged for a known, good, used one. If you decide to clean it up you may find an engine reconditioning company will "dunk" it in their hot cleaning tank for not very much money which saves a lot of time and mess and makes a much better job of it than trying to do it at home. Lot's of other remanufacturers have this sort of component cleaning facility. Locally, only a couple of miles away, on a trading estate, we have a remanufacturer of industrial electric motors and, as long as I can wait 'till he has enough of his own components to make up a load - never more than a week or so - he dunks things like this in his hot vapour chemical cleaner for me and charges "peanuts". They come out looking like new! I always like when I have an excuse to be visiting him - which is these days much less frequently than I used to - because he's always very interested to know what it is I'm bringing him he ha wants to know how it relates to and works on the vehicle. We have some very interesting conversations.

If you get as far as doing all this Carlit, don't then "spoil" all your hard work by subsequently tipping a can of flush in to "clean out" the rest of the engine will you! Better, in my opinion, to half the oil change interval using a good quality standard spec engine oil and let it's detergent package gently clean up the mess. There's probably a good case to be made for only running her for about a month, maybe 6 weeks, before the first change.

Whatever you end up doing I hope it all turns out well for you. Do keep us informed about how things work out please.
Kindest regards
Jock
 
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If oil is being supplied from at least some of the holes in the wee pipe, then I'd be removing the timing belt and cam bearing hold down bolts and then the camshaft itself. Now you can see the oil supply holes to the cam journals. At this age of engine it's going to be non interference, isn't it? So crank the engine over on the starter and watch to see what the oil supply is doing at the cam journals.
I was just thinking about this. I know the oil gallery enters the head from the block at the timing belt end at the front and travels through the gallery drilling in the head to the middle of the head where the oil supply pipe plugs in and subsequently then sprays oil on the cam lobes. It's been so long since I had a head off one of these earlier engines - with the oil spray bar - I can't remember whether the oil for the journals is supplied through the same pipe or whether the oil supply to the journals is separate? On the newer engines the oil goes through a gallery in the cam cover to reach the journals, be sprayed on the lobes and, on late model engine, to allow oil pressure to be modulated to the VVT pulley. So, thinking about it, I think the oil is supplied to the journals on the earlier engine through the spray pipe? Which makes fitting a new one even more important as it's going to be very difficult to properly clean the old one out? Anyone remember how Ford were always insisting on a new pipe being fitted on the Pinto engine when cam wear problems were encountered?
 
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Carlit

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Yup, I agree PB. It's a pretty typical example of what the inside of an engine looks like when oil changes are neglected. I can only think to add, Carlit, DON'T BE TEMPTED TO TIP A CAN OF ENGINE FLUSH INTO IT! If you do what may well happen is that a lot of that hard gritty gunge will be dislodged and travel round the oilways to cause even further problems. So, If it was me I'd be taking the spark plugs out and spinning her over to see what oil supply to the lobes is like. If oil is being supplied from at least some of the holes in the wee pipe, then I'd be removing the timing belt and cam bearing hold down bolts and then the camshaft itself. Now you can see the oil supply holes to the cam journals. At this age of engine it's going to be non interference, isn't it? So crank the engine over on the starter and watch to see what the oil supply is doing at the cam journals. If supply seems good check the cam lobe dimensions - they look a bit like there could be wear on the tips? Then clean up the carbon deposits on the cam and reassemble with a new oil pipe. If there is any question of serious wear or lack of oil supply to the journals the head will need to come off and be properly cleaned/exchanged for a known, good, used one. If you decide to clean it up you may find an engine reconditioning company will "dunk" it in their hot cleaning tank for not very much money which saves a lot of time and mess and makes a much better job of it than trying to do it at home. Lot's of other remanufacturers have this sort of component cleaning facility. Locally, only a couple of miles away, on a trading estate, we have a remanufacturer of industrial electric motors and, as long as I can wait 'till he has enough of his own components to make up a load - never more than a week or so - he dunks things like this in his hot vapour chemical cleaner for me and charges "peanuts". They come out looking like new! I always like when I have an excuse to be visiting him - which is these days much less frequently than I used to - because he's always very interested to know what it is I'm bringing him he ha wants to know how it relates to and works on the vehicle. We have some very interesting conversations.

If you get as far as doing all this Carlit, don't then "spoil" all your hard work by subsequently tipping a can of flush in to "clean out" the rest of the engine will you! Better, in my opinion, to half the oil change interval using a good quality standard spec engine oil and let it's detergent package gently clean up the mess. There's probably a good case to be made for only running her for about a month, maybe 6 weeks, before the first change.

Whatever you end up doing I hope it all turns out well for you. Do keep us informed about how things work out please.
Kindest regards
Jock
So you say it's better to take the head of and get it clean up at the engineers....and buy a other oil pyp that feed the oil to camp shaft
 
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So you say it's better to take the head of and get it clean up at the engineers....and buy a other oil pyp that feed the oil to camp shaft
Not without doing the checks first.

So, are all the oilholes spraying oil onto all the lobes? If not then the pipe is probably, at least partially, blocked.

Is a good supply of oil getting to the journals (the bearing surfaces inside the bolted down caps)?

once you know the answer to these questions then you can think about the condition of the camshaft and whether changing the head assembly as a whole would be beneficial.

Of course it's so difficult to give advice on this sort of thing without actually being able to see, hear and touch the engine but I think we may be off chasing a bit of a "red herring" (false or misleading clue). The OP has already stated that the water pump is dodgy and we all know that a seriously worn pump could cause the belt to jump teeth, so the best thing to do is get it changed and sling a new belt at it too as that is likely to have been weakened by this event. Don't know about the rest of you? but, although I've heard these engines with noisy tappets, - and they seem to run well regardless? - I've not yet seen one with damage to the cam bearings/journals? Of course there's always a first time?
 
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Carlit

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Not without doing the checks first.

So, are all the oilholes spraying oil onto all the lobes? If not then the pipe is probably, at least partially, blocked.

Is a good supply of oil getting to the journals (the bearing surfaces inside the bolted down caps)?

once you know the answer to these questions then you can think about the condition of the camshaft and whether changing the head assembly as a whole would be beneficial.

Of course it's so difficult to give advice on this sort of thing without actually being able to see, hear and touch the engine but I think we may be off chasing a bit of a "red herring" (false or misleading clue). The OP has already stated that the water pump is dodgy and we all know that a seriously worn pump could cause the belt to jump teeth, so the best thing to do is get it changed and sling a new belt at it too as that is likely to have been weakened by this event. Don't know about the rest of you? but, although I've heard these engines with noisy tappets, - and they seem to run well regardless? - I've not yet seen one with damage to the cam bearings/journals? Of course there's always a first time?
Ok so must I turn the motor by hand to see if the oil is pumping threw?.... cam shaft is of already ...the oil pyp feed was little dirty but clean it out
 

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If you turn the engine over - normal direction of rotation of course - then oil should come out of the hole on the forward side of the head beside the middle camshaft bearing above the exhaust manifold as you look at the picture you've posted. I did this by hand on my boy's Punto - just with a socket and ratchet handle on the front crankshaft pulley and oil started coming out of the hole after about half a dozen revolutions. If you were to spin it with the starter it should come out very quickly. Please turn the engine manually for a couple of revolutions first just to be sure no resistance is felt (I'm about 99% sure this is a non interference engine so there should be no chance of valves and pistons getting together but even so I'd still be happier if it was turned over very gently for a couple of revs first just to be sure?) Ifyou take the plugs out it makes it much easier to turn over and also to feel if anything does come into contact.

The shim faces on the tappets don't look too bad so that would seem to say oil has been getting through. The lower half of the front camshaft bearing has well baked dirty carbon deposits adhering. shouldn't be like this. Just all adding up to an engine which has not had regular oil changes. Some carb cleaner on a lint free cloth will probably shift it (I'd avoid scraping it with something like a knife to avoid damaging the surface). However the condition of the surface of the bearings looks pretty good with no signs of scoring or pick up. If the inside of the caps looks similar that would tend to say they've been getting at least enough oil to keep them "safe". The natural action of the cam lobes and valve springs will tend to push the camshaft against the top caps rather than the bearing surfaces in the head so, if wear is present, it might be expected to be more clearly seen on the caps?

If the shaft had been binding in it's bearings to such an extent that it was causing the belt to jump teeth I would expect to see some pretty catastrophic and very visible bearing surface damage. I also think it would be unlikely to just jump by one tooth and anyway, with a correctly tensioned belt, if the cam resisted turning enough to jump teeth then surely stripped teeth would be more likely? Seeing these pictures I'm more inclined to suspect that water pump than ever.
 
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