Oh dear, now you have really got me interested!! I wonder if that is Jeremy who posts on here?
You see i really enjoy the challenge of solving problems and now Mike has confirmed the M52 electronics are really complicated you've proabably made me even more interested in having a go!!
It's a bit of an illogical sequence but i'll explain my thought process.
It starts with a rather worn and noisey (tappets) M20 that has already done 170k miles. As most of you know, it's a 2 litre version and when I first drove the car it felt like a rocket, but you soon want more!
So i started looking into refurbing the head. Probably £400+ gaskets etc for a decent one but then the crank might be worn or the pistons, etc, etc. The parts for a refurb also add up to £200-300.
So I started browsing for a second engine but who knows if any other M20 would be better than mine
The BMW's drive so well most engines are high mileage and the low mileage ones could be clocked or unknown condition.
So then i start looking at M50's thinking there will be little difference and an easy swap. Then Patrick puts me straight and points out I need the gearbox as well since the M50 is mounted at a different angle.
He goes on to comment on the M52B28, so I took a look at Wikipedia and oh boy what an engine! It won all kinds of awards and I could go from 130bph to 190bph to 220bph - yikes!
It's all an academic exercise at the moment as I still haven't finished my car and haven't had the time to even drive it in the last four weeks! (House DIY, holidays, etc!)
I've already decided that if I was going to embark on this course I would buy a complete car to get all the necessary parts. Mike's input above has confirmed that is needed because of all the electronics. I broke the news to my other half that I was just thinking of swapping the engine but haven't owned up to thinking of buying another whole car and practically re-buidling the Sportster (well, she would only worry!)
Whole cars are dirt cheap for what you get and I think with the road tax going up soon they will get even cheaper.
Like I said, just a paper exercise at the moment...........(...but I've already invested in a Bentley manual - oh dear...)