KevB220

Any advice on the best place to get a pair of cylinder heads for a UK 99 turbo. Mine has cracks in the spark plug threads so I need to change them.

thanks

merlin24

iTrader: (1)

99% of the WRX/STi Version 5~6 cylinder heads have hairline cracks radiating out from the spark plug holes and dont normally cause any problems even when running big power.
If you feel the need to change them,then make sure you have the spark plug seating face on the heads machined,so the spark plug thread sits flush in the combustion chamber - its normally 2-3 threads short of flush and this causes the radial cracks seen around the spark plug holes.

Hope this helps,

Mick

KevB220

Ok thanks for that. Can they fail or would it be progressive? Engine is in bits at the moment and thought it best to replace, however if they dont cause problems is worth spending the money on replacements?

budd

iTrader: (5)

now you've got me worried I've never checked mine although nothing was obvious when I had the engine out recently, but if they don't cause any problems I'd leave well alone.