[Rick-sta]

Originally Posted by Christopher Price

It would seem that you either don't read what I've posted, or you have no knowledge of how the MOT testing system works. Retro fitting an engine into an older vehicle, rarely causes any problems, as invariably the older car will fall into a less strict Co2 category than the engine is being fitted to it. Sadly the reverse is true when fitting an older engine into a newer cat. An MG ZT 1.8T will be rated at 193 g/Km Co2, with the relevant authorities. The 620TI, (which is the engine that the OP is wanting to fit to his ZT,) was rated at 220 g/Km Co2. When the car is hooked up to the MOT system, the car will automatically fail on it's emissions, as it will produce more Co2 emissions than is allowed for that age/model of car. By the way, running a Cat with the engine, will not affect the amount of Co2 that the car produces, as they only lower the levels of hydrocarbons, carbon monoxide and nitrogen oxides, so my original point is correct and not "rubbish" as you posted earlier.

does declaring an engine change to the DVLA solve this emissions problem though? As there are many MG ZR and MG ZS T16 conversions on the road. There's also a MG ZR 2.5v6 and a MG TF 2.5v6 conversion on the road, both of which would produce higher emissions than their standard 1.8 160 engines? so there must be a way around is as there are newer cars on the road with older engines fitted and passing MOTs, such as 02-04 reg MG ZRs and ZS's with the older T16 turbo engine fitted.