EJ25D w/ 2.2L Heads Help (Frankenmotor)

[carkid]

I have a 1999 Legacy GT with the 2.5L EJ25D (dohc, phase 1) and I want to swap the heads. Now I know that I'll need new 2.2L heads with dual port so I don't need to change my exhaust, and I've read that you need a new timing belt. (Donor car will likely be 1995 Legacy 2.2L) Now here are the issues:

 

- Do I need to use the 2.2 head cam sprockets or can I use the ones from the 2.5?

 

- Besides the previous question, do I need anything else other than the 2.2 belt for the timing system?

 

- The bolt pattern for the 2.5 manifold I have has bolts in a straight line, however the 2.2 heads I've seen (1995 and older) have diagonal bolts.

 

- Can I use the 2.5l head bolts? I have a new set which I will use. 14mm 12 point.

 

- Is the bolt pattern the same? My current one has 6 bolts, 3 on top behind the top cam, and 3 down low behind the bottom cam.

 

- If the donor engine (2.2L) didn't have HG issues should I still get the heads planed by a machine shop?

 

- Should I get new valves seats/guides/valves/springs or is that overdoing it?

 

Pics are here (2.5l head, block and manifold): http://imgur.com/a/ExhsZ

[DOHCEJ22E1]

I have a 1999 Legacy GT with the 2.5L EJ25D (dohc, phase 1) and I want to swap the heads. Now I know that I'll need new 2.2L heads with dual port so I don't need to change my exhaust, and I've read that you need a new timing belt. (Donor car will likely be 1995 Legacy 2.2L) Now here are the issues:

 

- Do I need to use the 2.2 head cam sprockets or can I use the ones from the 2.5?

 

If this is a hybrid EJ25E, you need to obtain the custom hybrid head gaskets for the 2.5L that have the coolant passages for the 22E heads.

 

- Besides the previous question, do I need anything else other than the 2.2 belt for the timing system?

 

You will need the 22E intake manifold, 25D oil pump, and 22E dipstick tube.

 

- The bolt pattern for the 2.5 manifold I have has bolts in a straight line, however the 2.2 heads I've seen (1995 and older) have diagonal bolts.

 

This is why you will need the 22E intake manifold.

 

- Can I use the 2.5l head bolts? I have a new set which I will use. 14mm 12 point.

No. You must use the 22E head bolts as they are taller than the 25D bolts, and what your heads require for proper torquing/fitment.

 

- Is the bolt pattern the same? My current one has 6 bolts, 3 on top behind the top cam, and 3 down low behind the bottom cam.

 

Bolt patter is the same, bolt length is different. The 22E bolts are taller.

 

- If the donor engine (2.2L) didn't have HG issues should I still get the heads planed by a machine shop?

 

Yes, although there is a limit to how shaved they can be. Tread with caution.

 

- Should I get new valves seats/guides/valves/springs or is that overdoing it?

 

This would be ideal for a rebuild.

 

Pics are here (2.5l head, block and manifold): http://imgur.com/a/ExhsZ

 

BE WARNED. This combo yields a high compression ratio and if you have no way to tune it, it will fail in a short period of time. The 22E heads also don't breathe well enough to make any kind of decent power over the stock EJ25D, although power WILL be had. You will feel torque more than anything.

 

The stock Phase 1 ECU's are incapable of running these hybrids without a piggyback to adjust the timing. If you have the tools needed to reel this hybrid in, by all means, go for it. However, if not, it is recommended that you refrain from building this sort of frankenstein, as it is unstable.

[glastar]

I don't mean to hijack the thread, but are all 2.5 NA short blocks from 1999 on the same? I am have some 2.2 heads that have the combustion chamber enlarged to reduce the compression ratio when placed on a 2.5 block. I was told that they should fit any NA 2.5 block, but am thinking that the pistons must be different in 2.5 SOHC engines vs. 2.5 DOHC engines. Any ideas?