is there a difference between the sti heads and the heads found on wrx. on a version 2 plz

 

as far as what i can gather from what has been posted on this forum the only difference is in the cams....
more aggresive....

I'm after the same info for a V5 lol

 

Castings are the same but as above cam profile is altered.

 

Hello Mate,

The wrx heads usualy have hyraulic lifters and the sti's have solid shimmed lifters, the solid lifters are better at higher rpm.

I know the cams are different but do not know how different, I will have to measure mine when I get them and compare them to the wrx cams.

Regards,

Greg

 

the v1 and v2 sti heads are hydraulic lifters, the sti ra was underbucket shims

 

cheers for clearing that one up, do you know what the differance between the cams are pls?

 

You'll have to wait for merlin24 (Mick) to fill you in.

What he doesn't know about the EJ engine and drivetrain isn't, er, worth knowing.

 

dont think theres much difference tbh, the v1 sti's are basically wrx's with a few cosmetic parts as far as i know and i think that pretty much goes for v2's as well

 

 

He really is a wizard on the Impreza.

 

Joz and Prodriverules - i know a little bit about the EJ20's lol

As said above,the Version 2 WRX/STi both share a common head casting,valves,springs and hyraulic lifters - but the STi has lightweight hydraulic lifters and cams with a higher lift and slightly longer duration.

The main drawback with these heads tuning wise is they can can suffer from 'lifter pump-up/jacking' at higher power levels/rpm. This is one of the reasons the STi Version 2 RA and STi Version 3 onwards went over to solid lifters with under bucket shims.


Mick

 

The deviant has landed

 

Replyed to your other thread

Mick

 

Cheers Mick, wizards rule

 

i was under the impresion that the sti valves were injected with some thing to also keep the heat down.

not the sti v2. but the v3on
as this was why i got my sti v4 heads.
and this was why also they can take 500bhp no issues at all.

 

dont the v5 head have a tendancy to crack round the valve seats

 

v3 sti and on have sodium filled exhaust valves

 

Some Version 5~6 heads do suffer from cracks radiating out from the spark plug thread towards the valve seats - this is normally caused by the spark plug not reaching the end of the thread in the cylinder head ( usually about 2~3 threads shy ) and the open thread is exposed to the flame front.
You can machine the spark plug seat in the head to ensure the spark plug comes fully to the end of the thread on a non cracked head to prevent this happening.

The hair line cracks dont seem to affect the integrity of the heads/valve seats though - not personally seen a tipped/loose valve seat yet.

Mick

 

AFAIK - the Metallic Sodium filled exhaust valves were introduced on the STi Version 5 and the STi Version 3~4 were hollow non filled valves.

Mick

 

Yay! I possess sodium filled valves.

Really <ahem> cool!

 

call me an idiot but how do you tell the difference between hydraulic and solid lifters?. ive aquired allegedly v2 type ra heads and dont know how to tell. then i went onto tinternet and noticed ra heads that came up as images were all covered in crosshatching and mine arnt. mine do have the cloverleaf combustion chambers though

 

take one of the buckets out, if it has a shim they are solid, if not its hydraulic

 

+1
Genuine STi Version 2 RA heads will have INKO and EXKO valve codes too.
Picture below shows the RA Inner shim sat on top of the valve stem (bucket removed).




Mick

 

The Wizard unleashes another lightning bolt! FTW.

 

inkco and exco on the exhaust valves. me love you long time mick

 

thanks as well P1drifter. i only paid 67quid for these heads. took a gamble and it paid off lol thanks guys

 

 

whats the difference between v2 ra and v3 type r cam profiles merlin?

 

bargain price that

 

cheers p1. fleabay as well lol