i have decided to relive my youth and i bought a mk1 fiesta recently (81 1.1L) and have got it through its mot etc with lots of work however all the time i haved owned the car its has suffered from almost total power loss when the engine is warm and under load. when this happens full throtle is needed and the car just about ticks over on the verge of stalling. i have changed the plugs, leads, cap, rotor arm, condensor, coil and points which i have gapped. the problem is still there. the jet at the top of the carb ( ford not webber) seems to jet fuel fine when looked at with the air box off, does any one have suggestions as i do not want to give up on the car for the sake of this. the bodywork is sound and it has only done 41500 miles. if it makes a diffence the inside of the carb is black and the new air filter (ring style) i fitted recently has lots of fresh oil on the inside of it.

 

oil getting sucked into air box check all breather pipes and vent hoses and make sure oil filler cap wire filter is clear (soak it in some petrol )

 

could well be tight tappets

 

^^^^ sounds most likely to me....as your engine temp increases, ur tappet clearance closes up, if your gaps are already too tight then you can end up with them closing to the point of slightly opening the valves causing a major air leak in servere cases. And thus loss of power when hot