Hi all

well having much trouble with the scoob and no spare funds, my scoob has been a slow project, funds should be landing tommorow to get a big chunk done. Power fc, walbro, knocklink are all paid for now, pistons rods and bearings will be courtesy of API.

car was orig an Sti v2 ra, but the garage that carried out the conversion(2.5) swapped my heads for ones with hyd lifters and non-sti cams, David (API) recomended sti v3 heads, bit hard to find aren they? what would be a good equivalent? and can anyone recomend anywhere for the valves (back to shims) and maybe some headwork?

Thanks,

Adam

 

Were you aware they were going to do this?

 

no i wasnt, the garage WILL be sorting me with o.e spec(as car went to them) or better heads, i'm not happy, suppose i would have never known if i didnt do it myself this time. Not happy about it either.

 

btt

 

Kent dh22 cams are very similar to sti 3 cams

 

Not very similar at all to standard sti3 cams.

 

Rather than shooting me down, why dont you post something a bit more constructive!!

 

Depends what you're talking about. I know of the mythical wild sti3 cams, including the set out of Moray's car, and perhaps one more besides. The DH22 cams on the other hand, as you are probably aware are "very similar" to the cams used on the 98 WRC car. The DH22 have about 268deg total duration with 9.65mm lift. Sti3/4 cams have less than 9mm lift and from memory 256deg duration.

 

Too right!

The Sti 2 RA heads were very special in the first place, they were the only model fitted with 'Top Hat' under bucket shims. Ok, the cams weren't that special next to the regular Sti 2 (with Hydraulic followers) but the shimming method, buckets and collets were unique

 

I wouldn't be dissapointed with sti2 RA heads, although the wrx RA heads should be the same solid follower and top hat shim design.

Sti3/4 heads would IMHO be better still, but mainly due to some extra lift on the cams. The early RA heads are very capable in terms of power.

Hope you get it sorted soon.

Paul

 

Everyone always seems to go on about the v3/4 heads and seems to favour them over others. What are the differences between them and v.6 heads/cams???

 

they don't fit is the problem, different port spacing and stud pattern compared to the V1-4 heads.

 

I think Doug meant in terms of lift and duration

I would interested in finding all the cam lift & duration, does anybody know if this information is available?

 

I also have a set of STi RA 2 heads flowed so I'll be interested to see how they perform

pic of shims and top hat

 

People that are looking for v3/4 heads, do so because they are the best standard heads that fit their engine. Since v5/6 heads don't actually fit without a lot of hassle, it's a little pointless to consider them.

 

Picture of top hat shim, and follower.

 

I was just curious why peaople favour the phase 1 over the 2. Maybe its just down to availability? And since we're on the subject, what exactly is a phase 1.5?

 

If you have a phase 1 car, you can fit phase 1 (or phase 1.5) heads, you can't fit phase 2 heads. See above.

 

Think there's crossed wires here. I'm aware that you cant go mix and matching. Its just that most people seem to go down the phase 1 route for building engines with above average output. I was just asking to find out if there was any gains to be had? I thought that maybe there would be a difference in metals used, valve/stem sizes, ports/chambers, cam profiles etc. I take it there is minimal difference and the reason phase 1-4 seems more popular is down to availability.

 

TBH, i thought it was because my inlet manifold wont fit the phase 2 heads????

 

It's still mostly down to fitment. You can't just swap manifolds as the V5-6 idle valve is a stepper motor which can't be controlled by regular plug-in ECUs for v1-4 cars (which all have the same 3 wire ISCV).

If you have a v5-6 car and you want to change, you have the same problem, plus nowhere to put the coilpack depending on what you're changing.

It's a common view than the v3-4 heads are physically stronger and less prone to cracking, which is perhaps why the WRC cars use heads based on the v3-4 platform.

 

Question answered. Cheers Paul.