Just a quick question - are all A series rocker covers interchangable? eg - A12 will fit A15 etc etc.
Also sumps too?

a12 covers will fit A15 but I do remember once we had an A15 engine and for some reason we only had an A14 rocker cover and this wouldnt fit the A15 ( I think it was an A14 cover) The breather was to the front near the oil cap, and inside the breather was hitting on the rockers.

As for sumps I am not sure. I do know that there are 2 different sump gaskets, the difference is in where the oil dipstick goes.
But not sure if sumps interchange or not.

yeah i put a-12 sump on a-15

1200RC
You put a LATE A12 sump on an A15.
The shape of the sump gasket face is diferent on the right side on all A engines from about '73 with the introduction of the 120Y
A10's & real A12's will interchange with each other, but not with the late model versions

you can put a late a12 sump on an a15 IF you clearance the sides of the sump where the rod bolts are going to hit it.due to the longer stroke of the a15,the a15 sumps have indents for clearance.the easy way is to line up the rod bolts with the side of the sump,then using a round extension bar from a socket set,usually a 1/2 inch drive,& a hammer,place the bar on the side of the sump where it lines up with the bolts,then hit the bar with the hammer once or twice.this should give enough clearance.the cork gasket is wide enough to cover the little indents.cause it makes a godawful noise when you run the car if you don't.might even post some photos of the a15 sump i've got off the motor at the moment,just by way of illustration.

hmm, well i put an early a12 one on an a-15, there was some knocking but that turned out to be something else (long story but to do with modifications for turbo oil return)

i think there was a small knocking noise but at that stage i had choosen to ignore it, one or the other will wear out and the knocking will stop i figured???, i cant remember if there was knocking or not for sure now

im just remembering, the worse job ive ever done would have to be changing that sump

took 4 attempts too

1 to change from a-12 to a-15, but studs broke so i had to take it off again

2 i forgot the f'n oil pick up, yes i was finished when i realised

3 it leaked form the rubber, and knocked bad on the oil drain hole plug

4 with lots of silicon i beleive it worked

Yes there is nothing like starting a fresh built motor and hearing a KNOCK KNOCK KNOCK. A12 late sump to A15 duz just hit the rod end bolts.Tap a dent or four with ballpean hammer rite on the edge of the sump folded edge at top, one side only

yep, found that out myself, the hard way. luckily before engine was installed though