E30 Zone

i have the engine out of the 5 and was wondering what i should replace before i install it in the e30

Sump gasket as they do tend to weep a bit after time

replace the copper washer for the camchain tensioner too, common place for oil to pi$$ out on the M50

do the brether pipes( they split) and R/cover gasket while its out of the car, you can inspect the cams then too and clear out the breather box inside the R/cover

everything else is pretty robust, I regularly service an M50B25 equipped E34 with 307K miles on it, strong as an ox still !

My timing chain cover gasket seems to be leaking, but now Ant's just mentioned the tensioner washer it may be that

Wish id have changed as much as possible with the engine out now

Most important thing to check is the water pump. If it has a plastic rotor, then throw it as far as possible and replace it with a new one with a metal rotor.
Plastic water outlet elbows have been known to fracture as well. Fitting a new one will defer the disaster for several years, but early M50s had an alloy one.

ordered sump gasket, teromstat, rocker cover gasket , water pump, rear crank seal also was thinkinh of getting a new timing chain any need have any of yous heard of thyem breaking

Forgot about rear seal
The front one will need to be done with the engine in the car due to the 'special' technique
Heard of chains slipping but never a broken one

Check / replace clutch. Replace thrust bearing.