Technical Uno Turbo timing belt replacement
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Technical Uno Turbo timing belt replacement
Hello, welcome...
I suggest using the timing marks on the flywheel, which you can see through a small window in the gearbox housing. The leftmost mark (as you face the housing) is the 0-degree mark.
There is a set of marks at the other end of the engine to line up with the crank pulley, but these vary from model to model (sometimes on the plastic cover, sometimes a pointer fixed to the engine block) and can be very difficult to line up because they are located at odd angles to each other. The flywheel is more consistent in my experience.
I think that the cambelt cover on the Mk2 has a slide-out piece (look for a small tab on the back of the cover, and push it upwards). When this piece is slid fully-out, there is a small dowel pin that lines up with the notch in the back of the cam pulley. If it doesn't line up when the flywheel is at the 0-degree mark, turn the engine over one more complete turn.
The distributor is driven off the auxiliary shaft, so this will also have to be correctly timed. I suggest removing the cap of the distributor and marking the distributor body where the rotor arm points with the engine at the previously-described marks. It is very difficult to prevent the auxiliary shaft moving as you fit the new belt! So afterwards, remove the distributor (one 13mm nut) and turn if necessary to get your marks to line up again.
I don't think it is wise to advance the cam timing. I very much doubt that FIAT would have chosen the 'wrong' setting for the standard cam. If you have a modified camshaft, maybe it is more likely to be a good idea, but even then I would be suspicious. Bear in mind that the ignition timing will not be affected (improved) by any change to the cam timing.
You will have to improvise some way to set the cambelt tension. The tensioner bearing has two holes and flops around a 13mm nut. You need a slim ring spanner for the nut, and two short Philips screwdrivers, or screws, or some such to fit in the two holes. Then place a long screwdriver 'through' the two screwdrivers/screws/rods, and lever the tensioner against the belt.
Please, please make sure you turn the engine several times by hand (jack up a wheel and turn with top gear engaged, maybe with spark plugs removed) and recheck the tension of the belt in front AND behind the cam pulley, to make doubly sure that the belt is tight (and correctly timed) BEFORE you start the engine. It takes only a few more minutes and can save you many hours of work. Don't ask why I know this...
How tight? People say that you should just be able to turn the front section of the belt through 90 degrees with your thumb and forefinger. I have found, however, that a tension slightly less than this tends to avoid odd whining/scraping noises. The older FIAT engines of this type used to have a spring-loaded tensioner, which left the belt comparatively slack. I would say that I can turn my cambelt through about 120 degrees.
However, I make no guarantees and accept no responsibility for damage caused by the belt jumping teeth (!) I suggest that you should have the tension checked by someone experienced if you are in doubt.
Thanks,
-Alex
I suggest using the timing marks on the flywheel, which you can see through a small window in the gearbox housing. The leftmost mark (as you face the housing) is the 0-degree mark.
There is a set of marks at the other end of the engine to line up with the crank pulley, but these vary from model to model (sometimes on the plastic cover, sometimes a pointer fixed to the engine block) and can be very difficult to line up because they are located at odd angles to each other. The flywheel is more consistent in my experience.
I think that the cambelt cover on the Mk2 has a slide-out piece (look for a small tab on the back of the cover, and push it upwards). When this piece is slid fully-out, there is a small dowel pin that lines up with the notch in the back of the cam pulley. If it doesn't line up when the flywheel is at the 0-degree mark, turn the engine over one more complete turn.
The distributor is driven off the auxiliary shaft, so this will also have to be correctly timed. I suggest removing the cap of the distributor and marking the distributor body where the rotor arm points with the engine at the previously-described marks. It is very difficult to prevent the auxiliary shaft moving as you fit the new belt! So afterwards, remove the distributor (one 13mm nut) and turn if necessary to get your marks to line up again.
I don't think it is wise to advance the cam timing. I very much doubt that FIAT would have chosen the 'wrong' setting for the standard cam. If you have a modified camshaft, maybe it is more likely to be a good idea, but even then I would be suspicious. Bear in mind that the ignition timing will not be affected (improved) by any change to the cam timing.
You will have to improvise some way to set the cambelt tension. The tensioner bearing has two holes and flops around a 13mm nut. You need a slim ring spanner for the nut, and two short Philips screwdrivers, or screws, or some such to fit in the two holes. Then place a long screwdriver 'through' the two screwdrivers/screws/rods, and lever the tensioner against the belt.
Please, please make sure you turn the engine several times by hand (jack up a wheel and turn with top gear engaged, maybe with spark plugs removed) and recheck the tension of the belt in front AND behind the cam pulley, to make doubly sure that the belt is tight (and correctly timed) BEFORE you start the engine. It takes only a few more minutes and can save you many hours of work. Don't ask why I know this...
How tight? People say that you should just be able to turn the front section of the belt through 90 degrees with your thumb and forefinger. I have found, however, that a tension slightly less than this tends to avoid odd whining/scraping noises. The older FIAT engines of this type used to have a spring-loaded tensioner, which left the belt comparatively slack. I would say that I can turn my cambelt through about 120 degrees.
However, I make no guarantees and accept no responsibility for damage caused by the belt jumping teeth (!) I suggest that you should have the tension checked by someone experienced if you are in doubt.
Thanks,
-Alex
Thanks
I am replacing the belt because:
I recently discovered my car cannot reach topend. At 4000 rpm she seems bogged down and cannot acelerate beyond 160 km/h. My engine is in good condition, uses no oil or water, no smoke or overheating and fuell consumption is ok when driving in town.
Someone sugested cam timing as the culprit.
What are your thoughts on my problem.
The turbo manifold gasket is leaking but I dont think that is the cause
I am replacing the belt because:
I recently discovered my car cannot reach topend. At 4000 rpm she seems bogged down and cannot acelerate beyond 160 km/h. My engine is in good condition, uses no oil or water, no smoke or overheating and fuell consumption is ok when driving in town.
Someone sugested cam timing as the culprit.
What are your thoughts on my problem.
The turbo manifold gasket is leaking but I dont think that is the cause
The timing marks on the gearbox are a real pain in the arse to see...
You will need a timing light and a small one at that!
You will need a timing light and a small one at that!
Sir Dean said:
I would check you don't have an leaks anywhere and sorting the manifold gasket asap as if you have a boost leak that can massively reduce the performance!
Have you checked the turbo itself for damage?
Sir Dean said:
Would doubt its the timing then tbh but gotta be worth checking..
You checked the compression?
