legacycentral bbs

I want to swap my head.. mine is crap. to much hair.

okok just joking.

Seriously. A friend here is swapping is old 2.5RS 98 engine for a WRX one, and offered me the 2 heads of it's 2.5 engine (engine is diing slowly) for a low cost.

The heads are DOHC, and were planned 2 times, up to 0.015" or.. 0.15" .. ( 15 thousandth )

Question : Are these Heads swappable on our engine ? heard they are flowing better than the 2.2l ones.. and were a perfect fit, but I think that was for the SOHC heads.. not sure. Also, is that planned thing not too much ? will it rise the compression-ratio to high ?

thanx !

they will fit they do flow considerably better than the stock 2.2t heads.
from charts I have theyshow a compression ratio with this set up of 7:1.
now I'm not 100% sure on this but this is what I have found so far.

They will fit and they do flow better than the stock heads. We did cc these and I should be able to give you the comp. ratio tommorow. These heads are on the 400+ monster that we have running and it has had no major problems so far. You will have to provide an oil supply to the turbo and a drain.
AL(CO)
al@iwtu.net

Not so fast you guys!!!

Not that much of a bolt on operation

Take the time to read that...
http://www.xmission.com/~dac/library/headswap.htm

Yes.....read larry's write-up......you may change your mind.

Right it is far from a bolt on item I will try and get a list on the mods needed to do it right also. I think that the comp ratio should be higher than 7:1 as that is what we got with the EJ2Ot heads and it was pretty sad because of the low comp ratio.
One interesting thing is that the 400+hp car is running a stock EJ22t short block with no problems at 30lbs boost. The only failure in 2-3 months was a exploding lifter\camshaft incident. The block problems that it has had were with a fairly high milage EJ22t short block that did spin a bearing.
AL(CO)
al@iwtu.net

Ok the '98 heads have oil and water but you will have to make custom lines and make a drain into the oil pan (or We can furnish one) the intake manifold to use would be a '98 RS Impreza as your IAC will fit it. The compression ratio will be very close to 8:1 but a little higher becuse of the milling that has been done. Use the EJ22t head gaskets and the 2.5 belt.
This should work well like I said the high hp engine we have here is working very well except for the lifter trouble but that happened at very high RPM. Look at larry's post because I probably have missed something.
AL(CO)
al@iwtu.net

OK there is oil and water in the '98 heads and you can install fittings but custom lines will have to be made for the turbo and a drain will have to be made in the pan for the oil (or we can supply one). Your CR will be a little over 8:1 with the milling that has been done. Use the EJ22t head gaskets and the 2.5 belt and plastic. The best intake manifold for you to use would probably be a '98 Impreza RS as your IAC will fit. Should make a nice motor our 400hp+ engine is using this setup and the only failures were a exploding lifter and cam at very high RPM and another block spun a bearing but this was a older used short block assy. If you need any parts or advice we can help.
AL(CO)
al@iwtu.net

THe '98 heads have NA cams tho. I thought those were poo for a turbo system. I would go with the SOHC heads since getting proper cams would be much cheaper. in fact, in a SOHC setup you could just swap cams right?

The cam issue was something that I'm not sure if Larry took into account or not.

But typically, turbo cams will have less overlap duration between the intake & exhaust valves since the intake charge is being forced in, and does not require more time to scavenge the combusted a/f mix out of the cylinder.

There are some other issues like lift and other timing issues that probably should be addressed.

There is a thread in the Norm Asp. forum on nasioc where I listed the cam specs for the turbo and n/a cams.

Actually.....I might have posted it in here as well.....don't remember. But you can search if you're interested.

IggDawg wrote: in fact, in a SOHC setup you could just swap cams right?

I was contemplating getting different cams when I had my motor rebuilt. I was told by someone at cobb tuning that the SOHC heads are whats limiting the air flow, not the cams, so better cams wont help, not to mention I could not find any aftermarket cams period.


Mike