As the title says, what is the max bore that you can have on an A15? My engine's going to need new rings, and has a pretty decent ridge, so i figured it may be about time to just have a fresh bore and hone. I want to increase the displacement as much as possible while it's apart since I've been looking at quad carb setups and forced induction.

Next question is, would I benefit any with a larger bore, or am i pretty much at peak power with 1.5L?

Also heard about CA18DET pistons and rods possibly fitting an A15, meaning maybe it can be boored to 1.8L?

Thanks in advance.


Also, in a semi-unrelated note, I LOVE the A-series engines. Believe it or not, my engine is actually down to an average of 50PSI of compression (tested on multiple testers to confirm accuracy) and still runs like a champ. It smokes, which is why I'm going ahead with the rings since I just rebuilt the head.

CA has 83mm bore size... you won't get that out of an A

So their pistons won't work... the rods are the same length at 133mm and the big end is alos 40mm ... but don't know if anyone has actually fitted them to be 100 %
The small end is 20mm so different pistons and pins required or bush the small end

I'd stick to 77mm if you can get away with it... or 78mm max.. some go to 79 but you'd want a sonic tested block to make sure you have the wall thickness... and they tend to get hot faster
Bigger engines give more torque.... thats the biggest advantage
But anything will be a HP increase on 50psi comp

tetsusaru47
Go for the 77/77.5mm bore for an upgrade
it wont need sonic testing.

Otherwise peugeot liners from any 1.9 litre
sohc 8v head will most likely fit (to be confirmed)
once the block is machined for a wet sleeve setup.
This will make 83mm ca18de pistons a straight fit
as they have 29.9mm compression height.
Im hopefully going 83.5mm to leave room for further
rebuilds in the liners but most Pug/frog/french car
lovers have confirmed 84mm is safe but leaves no
room for further honing.

if you laws are strict the 1.8l options is good and
if the laws of your land are easy then 77mm with boost
and a single su will be awesome.

The law here allows us to swap L20B into our 1200s.

100hp L20B stocker: $300
or
100hp A15 modified: $1500

Your choice. Personally I think the A-series sounds better. But the L20B will be definitely faster even with the same peak HP, since it has a fatter power band.