hi folks i have recently removed my engine out my wrx ra and have brought a sti ver4 engine i was planning on dropping this in and seeing how much it would take..

but now have changed plans and decided too go 2.5 route iv sourced a semi closed deck 2.5l sti bottom end plan my plan is too change the bearing too acl race bearings and leave the rest as it is as its a low milage motor any way

my question is im running a ver 1 ra and was wondering what heads too use i was thinking ver 3/4 sti heads and was having these port and polished and set ov cams done also but will anything need too be done to the heads too match up with the block i.e combustion chamber matching??or can i leave it as it is and bolt straight on??

also anything else i need too change too drop the engine in??

 

Hi Matt,

As you know i too have a V1 Ra. and it is running a 2.5

I am running a Set of heads from from a 98 Type-R that have been ported and had Inconel valves fitted, with the Type-R Cams.

They will bolt right on.. but you should have an engineering shop clay the heads and pistons in order to calculate the Correct Compression ratio, so you use the right thickness Head gaskets.

You will need to source a Later water X-over pipe or have yours cut and welded..

Everything changes over, the 2.5 runs an extra breather in the center of the block, their are a few options with this.

1. Blank off this breather and do NOT use it.
2. Add in a few T pieces and plumb this breather in to the original breather system.
3. buy a RCMS oil catch can & Sump Return setup.. it is about £300 but as the 2.5 is renowned for using lots of oil this is a good choice and worth while investment. Ideally should be fitted when engine is out..




Derek

 

cheers derek forgot already u had the 2.5 in lol...i didnt expect too change to the 2.5 engine so soon but i want too clean whole car up and get it too the spec i want so might aswell do it all now in 1 than do it bit by bit...

im thinking sti ver 3/4heads ported polished i can get cams reprofiled too differnt specs so a set ov fast road/race profile cams. if i can il uprate the valves if not se the sti 1's

im thinking ov knive edging the crank and getting it dynamicaly balanced with the billet flywheel and billet front pully i already have ??

i was gonna leave std sti pistons and rods for now as there very low milage but plan too change the shells too acl bearings while crank is out..

i under stand the need too get compresson ratio worked out and il get head gaskets too suit my be cosmetic i think im not looking for bit power about 400 as its a road car so alonge with the light weight it should be a quick car i think