Morris Minor Owners Club

I was tinkering in the garage this afternoon, sorting spanners and other such technical stuff when my eyes wanderd to an engine i bought off the web for £10.98 (ironic eh?) I bought it to play with as i have never done a rebuild before. Well i HAD intended to take off the fan and water pump pulley to give it a clean up and a splash of yellow and the next thing i know, an hour had passed and i was looking at the big end bearings.
My question is, (forgive me if i use the wrong language) The big end bearings look fine with little sign of wear but the crank shaft shells are very copper looking .
Would you replace all the shells or just the crank ones.
ALSO
The big plate that the gearbox plate attatches to is cracked almost all the way across. Are these easily obtainable? Any idea of cost?

Whilst you have the engine apart replace all the bearings (crank and big ends) You will need to measure the crank to see if it has gone oval. If the mains are down to the copper there is a good chance it has been slopping around a bit. The backplate is not a worry as they are easy to get secondhand. Also, put a new ol pump in but don't forget to prime it first with vaseline....

For what the engine cost you, a set of rings would be the decent thing to do! Rebuild with a 12g940 head & MG Metro cam and you will have an interesting project!!

If you have a backplate plate already on your existing engine - no need to worry about the cracked one. Or - just weld it up!
Shells only worth while if the crank journals are dead smooth - and the crank is not worn oval. Be sure NOT to mix up the big-end caps - they must go back on the same rods - and the same way round.
Take the centre main cap off - that will tell the tale. Is it's down to the 'copper' (actually leaded bronze - I used to make the things!) then again - the condition of the journal is everything. If its' scored or oval - the crank will need a regrind.