Technical 1993 2.5 TD valve clearances
- Thread starter MickyP10
- Start date
Currently reading:
Technical 1993 2.5 TD valve clearances
If the 2.5 is an overhead camshaft unit then there is no simple adjustment.
It will have bucket cam followers with thick shims inside, which come in a range of thicknesses to choose from, after carefully measuring and writing down what the clearances are, with each cam base resting against the cam follower as you measure with feeler gauges. Having got the clearance on all 8 cams you then have compare what you wrote down to the makers stated clearance, note that intake and exhaust valves will likely have different values.
Any clearances that are out of spec need to be corrected by removing the offending cam follower and replacing the shim under it by a corrected value shim from the main agents spares counter. To do this the camshaft has to be removed and the timing disturbed.
Also you need to ask the question why are the clearances now not to spec? High mileage will erode both valve and seat closing up the gap a little. If they are all not too far out I would just leave it all alone but if you are plagued with one or two noisy ones you may need a full valve job, requiring the head removing and repairing with the valves inspecting and maybe replaced, oil seals replaced and perhaps even springs. Don' t forget Fiat insist you also replace the head bolts although I never do.
The cheapest way out for someone handy with spanners might be to remove the head yourself and send it to a specialist head repairer who will clean it, check it for cracks (!!) and return it with everything as it should be. Only if you have good tools and good working facilities should you consider head work yourself, as it's uneconomic.
It will have bucket cam followers with thick shims inside, which come in a range of thicknesses to choose from, after carefully measuring and writing down what the clearances are, with each cam base resting against the cam follower as you measure with feeler gauges. Having got the clearance on all 8 cams you then have compare what you wrote down to the makers stated clearance, note that intake and exhaust valves will likely have different values.
Any clearances that are out of spec need to be corrected by removing the offending cam follower and replacing the shim under it by a corrected value shim from the main agents spares counter. To do this the camshaft has to be removed and the timing disturbed.
Also you need to ask the question why are the clearances now not to spec? High mileage will erode both valve and seat closing up the gap a little. If they are all not too far out I would just leave it all alone but if you are plagued with one or two noisy ones you may need a full valve job, requiring the head removing and repairing with the valves inspecting and maybe replaced, oil seals replaced and perhaps even springs. Don' t forget Fiat insist you also replace the head bolts although I never do.
The cheapest way out for someone handy with spanners might be to remove the head yourself and send it to a specialist head repairer who will clean it, check it for cracks (!!) and return it with everything as it should be. Only if you have good tools and good working facilities should you consider head work yourself, as it's uneconomic.