legacycentral bbs

So I love thinking about things when I just wake up and my mind is completely clear of junk thoughts. As I was running stuff through my head it occurred to me that I people commonly use the EJ25D heads and cams when putting together a "Frankenmotor" or people with EJ22T motors who just want more open flow. The problem I have with that is that the cams they are using N/A cams. Couldn't you use the WRX EJ205 cams which should be a better option for a turbo motors? The ECU should read their position just the same as the rest of the cams used correct?

Has anyone actually performed this swap? If so, how well does it work out?

The Phase 2 cams have a totally different thrust design and do not work.



EJ20K cams are the ones that work in EJ25D heads.

OR... late model ej20g (93-96), ej20h, ej20r cams all work as well.

Which explains why the intake manifolds cross over as well then. Ok, thanks for the heads up on parts swap over. I'm going full EJ20G heads (been purchased for almost 2 yrs now) so I won't need to go this route, but it may help out someone else in the future with their build.

I was told that cams from heads that use hydraulic buckets do not work in heads that use shim-over buckets.


Are the heads you listed not hydraulic?

As far as I understand they should work just fine. You'd just have to re-shim the heads. I'll check tomorrow as I have both sitting on my garage floor.

EJ20G hydraulic cams don't work.

Why dont they work?

That doesnt make sense because I just compared my ej20h cams and they will work fine in ej25d heads. I actually put the 20h cam INTO the 25d head and it was all fine.

I think you're thinking of EARLY ej20g heads with the rocker arms. Those wont work (but why would you want them to... flat cams...)

but since the 93-96 WRX heads (Hydraulic Buckets) (which I've had) are basically the same as ej20h twin turbo heads (Hydraulic Buckets) (that I have) which are basically the same as 96' ej25d heads (Hydraulc Buckets) which are similar to 97'+ ej25d heads (Shim/Bucket) which are ALMOSt identical to ej20k heads (Shim/Bucket, Bucket/Shim, Shimless Bucket) (with the exception of the valvetrain... 20k has stiffer valve springs, wayyy better cams etc.) all the cams since the 93 WRX 20g heads up until the last of the 20ks should all be interchangeable.

I will say this tho... I would much rather use the 25d heads with the shim/bucket setup with a port and polish and the 20h cams than just using the 20h heads...

The 25d heads have a much taller valve spring and a much wider one. The bore (probably wrong term... but idk what is the proper one? diameter?) of the bucket on the 25d heads is MUCH larger than the 20hs... In fact... You can fit the 20h bucket INSIDE the 25d bucket.

I think I'm going to have the 25d heads rebuilt, pnped, and get a stiffer set of valve springs for the next motor.




But to answer Dans question...

Yes, Hydraulic BUCKET cams will work in shim/bucket heads. However I'm pretty sure Matt is right that Hydraulic ROCKER cams won't.

thank you for the clarification on this!!

smh0101 wrote:Why dont they work?

That doesnt make sense because I just compared my ej20h cams and they will work fine in ej25d heads. I actually put the 20h cam INTO the 25d head and it was all fine.

I think you're thinking of EARLY ej20g heads with the rocker arms. Those wont work (but why would you want them to... flat cams...)

but since the 93-96 WRX heads (Hydraulic Buckets) (which I've had) are basically the same as ej20h twin turbo heads (Hydraulic Buckets) (that I have) which are basically the same as 96' ej25d heads (Hydraulc Buckets) which are similar to 97'+ ej25d heads (Shim/Bucket) which are ALMOSt identical to ej20k heads (Shim/Bucket, Bucket/Shim, Shimless Bucket) (with the exception of the valvetrain... 20k has stiffer valve springs, wayyy better cams etc.) all the cams since the 93 WRX 20g heads up until the last of the 20ks should all be interchangeable.

I will say this tho... I would much rather use the 25d heads with the shim/bucket setup with a port and polish and the 20h cams than just using the 20h heads...

The 25d heads have a much taller valve spring and a much wider one. The bore (probably wrong term... but idk what is the proper one? diameter?) of the bucket on the 25d heads is MUCH larger than the 20hs... In fact... You can fit the 20h bucket INSIDE the 25d bucket.

I think I'm going to have the 25d heads rebuilt, pnped, and get a stiffer set of valve springs for the next motor.




But to answer Dans question...

Yes, Hydraulic BUCKET cams will work in shim/bucket heads. However I'm pretty sure Matt is right that Hydraulic ROCKER cams won't.

I hope the valve springs in my 25D heads can handle the 20K cams I have in there now. Hmmmmm.

And to bring up a dead post...

Spencer, did you ever run the 25d heads with 20h cams?

20h heads the hla bucket type, they could be run in a 96 ej25d head, but not recommended on an ej22 because the combustion chamber is right at 2mm wider than the bore.