1380 pistons, what cc dish?
Turbo Mini Forums

As above, seen some 73.5 omegas for sale, what cc dish do most prefer to lower the c/r? Can they be machined? And are 1380 motors reliable enough? My block is already 1275cc linered so im either going 1293, or 1380cc
Thanks chaps.

Are you sure you can go to 1380 if its already linered ?

When I asked I was told its not on.

Im not sure, i guessed the liners need to be removed, then go from there.

Factory liners are usually fitted for a reason, namely porus casting, so would be hit and miss removing the liner and boring to 73.5mm, which can be done on a factory linered block.

What you have to find out is whether they are factory liners

as for the cc question, off the shelf options are 7cc and 11cc, or at least there used to be. if you want any more, you'll have to machine them

Ah thanks, how can you tell of factory liners or not? This isnt the block i bought off yourself as i bought a short engine instead, and sold that block to a friend (the chap who bought it back for me haha)
Just thinking about it, these could be new liners as it was a fresh built 1275 short engine, std pistons with new rings which i have removed.

Edited by Carlzilla on 2nd Aug, 2011.

The omegas in question are 8cc, so im guessing theyd need to be machined, the pistons on rods are 100 quid, am i better off just buying a new set of +0.20's with 10/11cc dish?

The other thing with liners, even if they weren't factory fitted because of porous castings, is they take up a fair bit of room. So when pressed out, there may not be enough metal left to bore 73.5mm, especially as you should really be offset boring for 73.5mm so you need a lot of (good) metal remaining between 2 and 3 once the liners are pressed out.

Also, certainly back in the days of my youth messing about with Imp engines, the aftermarket liners (on dry liner Imp blocks) were stepped at the top to make sure they didn't move downwards and to make sure the gasket sat fully on the liner - so if you pressed them back out, there would be a recess where the gasket would normally sit. I don't know if A Series liners are the same but worth checking.

Schrödinger's cat - so which one am I ???

i used 10cc cast omegas in my 1380 - but depending on the amount of boost you want to run will that will dictate what head you go for.

Stick with the +20's for simplicities sake. Unless you want to find another block.

If something is worth doing, it's worth doing half of.

Fair comments lads, thanks, shall just stay 1293, just that the 1380 omegas were reasonably priced, im just waiting for a 1293 set to appear as im in no rush.

If they were the ones on TMF then you would have still been shelling out a min of £105 for a ring pack on top of the base price. Which IMHO makes them far less of a bargain.

If something is worth doing, it's worth doing half of.