[marc l]

hey guys i got some questions about the heads i recieved

now i was certain that the DOHC 2.5 heads had the clover leaf combustion chamber but mine isnt... its kinda like a wrx style.

also i was under the impression that they had solid buckets with shims
and this one has hydraulic buckets...

if anyone has any clearity that would be great

cheers

marc l

 

[Storm]

Your information was wrong.......

They all have the same pentroof chamber. In 96, they had HLA's (and bigger ports) but went to the shim/bucket design in 97.

Your heads are good for 8000+ rpm with no mods. Cams from later years will fit, but the valves, lifters and spring dimensions are unique to that style, so you cannot switch to later year types.

 

[marc l]

can u define pent roof?

ive pulled a few apart and ive never seen this design... plus it has hydraulic buckets...
i will take pictures today of it... and post it up.

 

[FuJi K]

http://www.rs25.com/forums/showpost.php?p=1393778&postcount=78

 

[Storm]

Only if you define "clover leaf" design.....

can u define pent roof?

ive pulled a few apart and ive never seen this design... plus it has hydraulic buckets...
i will take pictures today of it... and post it up.

 

[mxpunk]

the hla heads are awesome..good for gnarly high flow boost!!

i am still contemplating picking up a set of these heads and building a ej22 block and going high boost

 

[marc l]

welll its the shape of the combustion chamber, its rounded around all 4 valves. kinda like a 4 leaf clover

so i got it confirmed today that these are the 96 HLA heads

so ive nver delt with these heads before.. cna someone give me a quick break down on them?

you say the valves are unique to it, but are there any other subaru heads that match? jdm stuff?

also are the hyrdaulic buckets a neucence? ive heard of collapsing them before and dont wanna have to deal with the noise
and loss of performance and the having to replace them.

all the info would be greatttttt

and also

the hla heads are awesome..good for gnarly high flow boost!!

i am still contemplating picking up a set of these heads and building a ej22 block and going high boost

thats exactly what im doing

 

[FuJi K]

I don't know if you've seen this thread.
http://www.rs25.com/forums/showthread.php?t=48323

the '96 are the BIGGEST intake port heads we have. The exhaust ports on the PHASE2 heads '99 2.5L SOHC and all USDM DOHC turbo heads are larger than the EJ25D exhaust port but smaller intake ports.

 

[Storm]

I've got bare 96 EJ25D heads sitting in my garage. All the HLA's are in good shape, and they have been ported and heavily polished. I bent some valves, but other than that, they would make a great base for a high boost subie!!!

 

[marc l]

did u run those heads? how were the HLA's? i mean if you think about it subaru changed it after that one year to a bucket and shim, so were failures high on them?

 

[Storm]

Subaru used them on some of the JDM STi motors prior to being used on the 1st EJ25D. I did run the heads for awhile.....But I messed up and didn't torque the cam pulleys. It ran beautifully until the pulleys loosened up and threw the timing belt. That's why the heads are bare now.....

You will like them, they really are good heads.

 

[marc l]

i hope soooo


from what ive heard there sounding better and better.
just gotta get some extra cashhh to get the valves and what nottt

anybody know a good line on cams? or are regrinds the way to go?

 

[impreza93]

im buying a 98 RS that's rusted out with a good 2.5 dohc motor, I wanna put the 2.5 in my 93 impreza but I wanna get away from pulling the dash and such. I know 1.8 heads will work on a 2.2 phase 1 and 2 engines but my question is will 2.2 phase 1 heads work on the 2.5 dohc motor to do away with all wiring?? any info on this would be awesome

 

[username83]

You can swap your ej18 wiring harness onto the ej25d, bolt it in and be done with it.

 

[2slo4u]

Make sure you can source new hydro adjusters before deciding to stay with the heads. We can discuss benefits of intake port size all day long but a hydro adjuster is still more likely to cause issues than a solid bucket design regardless. Not to say they won't last a very long time, but 1 - you can't know the actual mileage and how well the engine was maintained and 2 - solid buckets are very simple and more reliable. The only benefits of a hydro adjuster are that they will maintain good valve clearance IF they are working perfectly which means you won't ever have to adjust clearances. I checked my ej20k 1997 heads and even though they are a little old and really have unknown mileage, all clearances were still in spec. If you keep your oil changed regularly, solid or shim with bucket heads will go a long way with zero maintenance. You can also port and polish any of the heads and get larger diameter valves installed.