19 replies to this topic

[soobie_newbie67]

Frankenmotor time! Those are the right heads, right???

[Fairtax4me]

Depends on what kind of frankie you want to build.
Usually the high compression version Frankie is a 25D (DoHC 2.5) block with 2.2 roller rocker single cam heads.

[soobie_newbie67]

Orly? What's the other one???

[cal_look_zero]

Slow down tiger.

Chances are if someone "gave" you a DOHC 25, you need to pull the oil pan and witness the phenomenon known as "The silver milkshake". 25Ds have a nasty habit of eating rod bearings. Not that it's the end of the world, but it's more trouble than it's worth.

Ask me how I know...

I'm in the process of sourcing an EJ257 (STi) engine to replace the 25D that I salvaged for my frankie. It's not that it's a bad engine by any means. But I have experienced my fuel cut at 6200rpm, and I doubt those internals will last me long at that rate...

The only thing the heads are good for is either selling, reusing on the 25, or slapping onto a 22 and turboing it.

[soobie_newbie67]

Actually I wanted to use the heads on my 2.2. One of the rods are bent cause it was ran low on oil. On the ej25. It has a bent rod. Not my ej22.

[grossgary]

I think you have it backwards. Frankenmotors are typically EJ25 blocks with EJ22 heads, you're talking about doing the opposite which would not only reduce compression but give you those debacle of a nightmare heads to maintain - shim over bucket nearly non-adjustable valves that burn exhaust valves, more expensive timing belt, twice the cam bearing surfaces, plastic sprockets, and seals to fail, and almost positively heads that have been previously overheated.

[soobie_newbie67]

Ok then. I'll just chill with it then till I can tear it apart and see if the cylinder walls can be honed out and reuse the block with a new rotating assembly.

[ocei77]

There is an alternative.
See; http://legacygt.com/...22e-190650.html
The only thing you will NOT have to do is swap harnesses.

O.

[GeneralDisorder]

The 25D heads are good for turbo builds. They are not "frankenmotor" compatible.

You need to use the block - which is probably trashed if it was free. You can rebuild them but typically it is not cost effective to do so unless it was a head gasket failure that resulted in it being replaced without being severely damaged in the process. Then doing ACL race bearings and new rings is not that bad of an expense if you do it yourself.

DO NOT hone the block. Just install new bearings and rings (cast iron, not chrome faced) and run it.

GD

[cal_look_zero]

The 25D heads are good for turbo builds. They are not "frankenmotor" compatible.

You need to use the block - which is probably trashed if it was free. You can rebuild them but typically it is not cost effective to do so unless it was a head gasket failure that resulted in it being replaced without being severely damaged in the process. Then doing ACL race bearings and new rings is not that bad of an expense if you do it yourself.

DO NOT hone the block. Just install new bearings and rings (cast iron, not chrome faced) and run it.

GD

Where the hell do you find cast rings for these engines? I have yet to find anything non chro-mo.

[GeneralDisorder]

Chrome faced or Chromoly?

All the rings I've seen have been cast without facing.... I assumed they were cast iron but it's probably some type of ductile high tensile casting....

I just make sure they don't have a shiny facing material.

GD

[cal_look_zero]

Gotcha. I've been on the hunt for a set of genuine cast iron rings, but haven't ever found any aside from a custom set that would be $$$. The general market ones are pretty much all the same from what I've seen.

Thanks.

[soobie_newbie67]

Ok, the REAL problem is he threw a rod bearing. it was pretty evident when i went out and turned the crank back and forth and you can feel and hear a clunking from within.

Now i know you guys will say everything against it, but for some reason i wouldnt mind just putting this whole engine in my car. It came out of a 1996 Legacy GT. What the guy was doing was spinning donuts in the snow doing 6k for 5 minutes straight and heard clunk, then the non stop knocking, and thought he bent a rod.

So, what i want to get at is this: all i ever hear bad about this engine is its tendancy to blow head gaskets (and throw the rod bearing xD). You guys told me about all the problems with the EA82 Turbo and addressed them to make it reliable. I'm pretty sure one of you guys nows a fix to solve the HG problem with the EJ25D. Links to a post or an answer is always much appreciated.

[Fairtax4me]

Updated MLS style head gaskets, deck the block and mill the heads for perfectly flat sealing surfaces. Run Subaru anti-corrosive coolant with the conditioner.
Properly cleaned and properly torqued with MLS gaskets it should have 200k or more miles with no trouble. This assumes proper cooling system maintenance is done to avoid overheat situations.

[GeneralDisorder]

The heads will be trashed. Cam journals wiped out from rod bearing material.

GD

[soobie_newbie67]

Quite possibley. But he shut it down right when the noise started and had it towed. Oh well. I'll just frienkenmotor it. The block is perfect.

[GeneralDisorder]

The block is perfect.

Rod knock is far from "perfect".

GD

[Gloyale]

Chances are the crank is trashed too, and will need more than just a polish.

It'll need ground, and fitted for an undersize bearing set.

It's also possible that loose rod swung around and damaged some of the webbing in the middle. won't know until you pull the pan and split it.

Hate to say it, but I wouldn't have too high hopes of a cheap fix.

Rebuildable sure, but it's gonna need at least the crank machined, and probably the deck surfaced.

From the sound of it, your buddy was floggin that engine pretty hard, surely not for the first time either. Are you sure you want that engine????

[soobie_newbie67]

I already nabbed it. It was free. I might just tear it apart to learn about it now.

[Fairtax4me]

Free's the perfect price for an engine to tear apart.