Head Advice

[Jem]

hey guys,

i picked up a bare rb25 head with valves, retainers and GTR springs, as i've got an engine that spun a rod and made a nice dent in one of the combustion chambers in a spare engine i've got here..

anyway, i took a closer look at the head today, more specifically at the valve guides and it appears that the first 4 guides on the intake side are different and longer than the rest of the intake side, and are in good condition.. out of the remaining 8 guides on the intake side a few have cracks and chips taken out of them, although all of the guides on the exhaust side are still fine (they look different to the ones on the intake side although i put this down to the different valve sizes)..

i'm thinking that perhaps the first 4 valves on the intake side are the only ones in good condition, and the remaining 8 have all actually had the top bit of them snapped off and others had chips and cracks made in them..

basically i'm wondering how seriouse this actually is, the maximum power i'd ever really be putting through the engine in this configuration is 250kw atw and the rev limiter is set at 6500 (rb25/30), and the head is really just an interem solution till i can build up something better

should i have new guides installed into the head? if so is there any cheaper solution than the HKS / tomei guides which seem to retail upto $400 a set?

also should i have the valve seats machined before i put the head back together? they look to be in pretty good nick and the head came off an engine with good compression in all cylinders..

thanks for your help in advance,

marcus

[Slim Mat]

The valve seats should be ok, especially if you are trying to save a few quid. You did say that this head is just for the mean time.

Not sure about those guides though, I wouldn't trust them. Better off at least getting them checked by someone who knows. The other thing is, if you get some flash ones now, you can always reuse them in the new head build up in the future. Best bet would be to shop around online and do some research on the guide you want, or ask local workshops what they use and get quotes off them.