Phase 2 (v5) heads on phase 1.5 block. Anyone done this before???
 

Hi guys this has probably been asked a million times already but the info I've found so far has been somewhat confusing. Has anyone actually fitted the later phase 2 heads from a version 5 or 6 to an early closed deck sti block? I understand the combustion chambers and piston crowns differ slightly? Wondered if anyone has done this before and worked out all good? I have a v5 sti with a wrecked block. I also have a spare cdb on excellent condition which I'd like to use but I need to retain the phase 2 inlet manifold so I'd need to use the phase 2 heads. Don't really want to use adaptor plates as I've heard it's not that straight forward. Would appreciate any help guys. Thanks

As long you get the correct thickness head gasket, I dont see you having any issues doign this. I used a newage block with sti 3 heads which required 1.1mm iirc, with your being and older block with newer heads think it will be 1.6mm. whoever you get the gaskets from should advised you of the correct thickness for your spec for it to work

OK lovely thanks mate Ive already purchased 1.6 mm steel gaskets to replace the chappy composite ones perhaps Il give it a go then. Thanks again

Deja vu.........I thought I answered this last night.

Apologies bud I don't doubt your knowledge lol I just thought I'd word it different to see if I get any more opinions. Looks like im going ahead with it, got some arp head studs and nuts aswel now. Thanks again

No worries :thumb:

Have a word with the guys at enginetuner.
They built my engine with cdb and p1 heads.:thumb:

1.6 are too thick if the heads and block have not been skimmed massively. The extra CC is in the V5 heads, so if they are definately phase 1.5 heads (not phase 1) you need 0.6mm gaskets to keep the CR std.

Right ok that's thrown me off lol. I read that you should use the gasket meant for the block not the head but I have since found out there's a difference of approx 4-5cc between the phase 1 and 2 heads. Im now thinking of bitting the bullet and installing the correct square cut pistons( that match phase 2 head) in this block. The v5 engine I took out was built at api with wossner pistons etc all of which seem in reusable condition as do the rods bar number one. Are the cranks in these old cdb's any good aswel?
Thanks again

It's not as straight forward as you may think-
Phase one engines with 'dog bone' type pistons need a 1.6mm gasket as the pistons stick out of the top of the block by approx 0.7mm
Phase 1.5 have the square type pistons these require 1.2mm gasket if using v1-4 heads as the heads are 47cc
Phase 2 (WRX) have the square HBR type pistons which have the same cc as the phase 1.5 so you need 1.2mm gaskts using v1-4 heads or 0.6mm if using phase 2 and new age heads (49cc)
This is all assuming that no major material has been removed from the block/heads, then you would need to CC everything to get it 100%.