STi 5 cams in WRX heads ?
 

One of my STi 5 heads suffered a nasty accident, bending valves and damaging the head casting.

I know that the STi heads have bigger valves and the 'under bucket' shims but could I use the STi cams in the spare set of newage heads that I have lying around ?

I'm guessing that all the cams do is control the degree and duration of valve opening, if so I should still see some benefit over the 'milder' WRX cams ?

Anyone ?

Can repair castings and have done some that you would think are way beyond repair.

Cannot get any genuine group a heads or wrc but repair them and the finish is as new so if you need repair then you can contact me.

Yes I think that will work in a set of new age heads, do not think you will be able to tell on the road a difference but in output figures you will see.

Off top of my head V5 thrust setup is same so compatible for new age heads.

All the best.

Many thanks, the head casting is really mangled around the valve seats with deep gouges and metal 'missing'

I was only wondering if there would be any benefit re-using the cams in the spare newage heads that I have.

Yes you should see some midrange/top end improvement fitting the STi Version 5~6 cams as the Inlet cam has 242 degrees duration,exhaust 248 degrees and both have a higher lift over the WRX cams (Inlet 240 exhaust 240).
This will give you 2~3 degrees more overlap with the STi cams to move the powerband up the RPM scale hence the midrange/top end improvement.
The newage heads should have selective buckets for valve clearance adjustment which is an added bonus over the under bucket/inner shims of the STI heads.

Mick

Cheers for the info Mick !

All V5 engines onwards have the same dimension valves, its a myth that STI's have bigger vaves, its just the cams that change as said above. The increase in overlap also means you can get more ignition advance in as the dynamic compression changes, hence the change to the power delivery.

I thought that the STi valves had different numbers stamped on them compared to the valves fitted to WRX or UK Turbo heads ?

So just the cams and under bucket shims then ?

I've also got a set of sti5/6 cams lying about on the shelf, and have a similar query.

My bottom end is built to be safe to 8k, but it has new age WRX heads. I'm assuming that the rev limit on the heads (7200 or whatever it is as std) is due to the springs, so would I be able to change the springs and cams and rev it to about 8k?

I don't particularly need power at the extra revs, but sometimes I find I run out of revs say 50m before a corner, so it'd be good to be able to hold the gear for the extra distance.

If it's a matter of changing springs, how much am I looking at for a set including any necessary ancillary bits?

There are differnt valves fitted, some are filled with sodium to help with cooling but dimensions are no larger. I'm not 100% sure if any version have stiffer springs as std, for all the heads ive assembed I can't say any feel harder to compress, so my educated guess would be they are all the same rate. If you realy want to rev it that high you need double springs and decent retainers.