im new to imprezas & im most sertain ive bent a valve on my impreza by a friend doing shoddy timing

anyways the engine i have has sti version 5 heads, whats the differance between the versions/heads?

also is it an engine out job or can it be done with the block in?

heres the spec if it helps

(coppy and paste job)
Engine:
2.5 usdm short motor with forged internals and sti 5 heads
Full rebuild with every seal replaced (15k since build) 85000 miles total done by KR performance
Uprated oil pump
Full service history
Andy Forest 20g td05
Nismo 740cc injectors
Uneaqual stainless headers
Full 3" turbo back Apexi N spec exhaust
Fully heat wrapped open mouth downpipe
Lightened and balanced flywheel
Re-built gearbox
Short throw shifter
Hks Front mount + hard pipes
K+n intake
SX fuel regulator
Samco intake
HKS SSQV blow off
Walbro fuel pump
Oil catch tank
3 port boost solenoid
Apexi ecu with commander mapped by Andy Forest
Detailed engine bay

 

some say heads can be done whilst still in the car, but imho engine out swap over new gaskets, a day tops depending how you are with the tools. i'd also replace heads like for like, hth

 

okey dokey,

whats the differace in version 5/4/3 etc heads anyways

 

A cost effective repair would be to replace the damaged valve(s) rather than swapping the heads.
The main difference between the STi 5/6/P1 heads and earlier heads is the Inlet Manifold bolt pattern - staggered on yours and inline on the 'up to Version 4' heads, so the inlet manifold is not a straight fit/swap.
Also,none of the Valve's,cams,springs from the earlier heads will fit yours either.

Although you can get the heads off with the engine in the car - its a mare of a job to do so and also difficult to clean the block faces without getting debris into oilways/sump.

Mick

 

As merlin says, doing a proper head replacement job on the EJ with it in situ is akin to wallpapering your hallway through your letterbox! i.e. it's possible... but would you really want to do it!

I love that (much used) analogy

 

Cheers, missions on for tomorow then