With the old block unusable in its state I decided to bring the final plan forwards... So, with a bit of hunting I found a 'rebuilt' 2.5l STI shortblock on ebay.
Final build will consist of 2.5 sti upgraded with forged pistons, V3/V4 sti heads which I will rebuild, upgrade one of my turbos to td05-20g, new bigger injectors, new oil modine, sump baffle plate and probably some other supporting mods being topped off with a remap on an ESL daughterboard, probably by Bob Rawle when he visits API.
The shortblock as I received it. With some thought I decided that I will always feel uneasy about the stock pistons as they haven't got a very good reputation. After a chat with David at API (well respeced Impreza engine builders only 5 miles away from my house!) I decided to go with some forged pistons. Supertechs have a good reputation for not being rattly like most and API have experience of them so that's the way I have gone. The stock rods are good for 450bhp ish as they are the latest spec ones. My goal is a good 400bhp.
Time to split the block as the cylinders needed honing to fit the pistons. It would also give me a good opportunity to inspect the 'rebuild'.
The big end bearings were supposedly new! I've replaced them with ACL bearings
Main bearing clearances checked with plastigage, they are all good, as are the bearings. Luckily this is the better nitrided crank too..
Block halves back from API after being honed, they have been done to 3.8thou piston clearance.
Here's the first supertech piston, I've gapped the rings to specs..
I'm quite enjoying this engine building lark, this is my first attempt!!