V3 V4 Heads
 

Hiya guys, whats the actual difference between v3 and v4 heads and how can you identify the difference between them?

Cheers Guys :thumb:

None AFAIK. Mick (merlin24) is the expert on these.

:norty:


The head Castings/valvetrain/and cams are the same, although some of the late Version 4 engines came with the later single bolt cam belt tensioner(not head related though) - the difference is between the WRX and STi Version 3 and 4 heads.
It has been said that the Vers. 4 STi heads came with milder cams(lift & duration) but i have never seen any difference in the cams TBH.

WRX/UK Version 3 + 4
Composite Head Gaskets.
IDN/EDN Valves.
48mm Orange Coded Valve Springs.
Outer Shim Buckets 33mm OD.
LHB/RHB Head Codes.

STi Version 3 + 4
Thick MLS Head Gaskets.
IH/EH Valves.
56mm White Coded Valve Springs.
Inner Shim Buckets 33mm OD.
LHB/RHB Head Codes.

Hope this helps you scoobycraig.

Mick

absoltue spot on mate! Really appreciate it dude.

No worries :thumb:

LOL I swear there is nothing Mick doesn't know about v3/4 engines. I've lost count of the amount of times I've had to ask him something. But having had a set of WRX4 and a set of STi3 and STi4 heads apart, the two STi versions looked the same to me.