Cheers Conrad, i willbe in touch.

 

What waterways on the short motor ? It's an open deck block

 

The EJ25 will need a rebore(or confirmation that the bores are round, parallel and square), pistons and rods before you can safely put 400 hp through it. New rods may have to special order, as the the early EJ25 engines have different big end journal sizes, and the rod length is different to EJ20 and EJ257. You need to confirm the position of the crank thrust bearing, the smaller journal crank has the thrust bearing in the centre. Checking the block is not sufficient as Subaru have used a phase 2 block casting with phase 1 cranks.

Many EJ25 engines that are about, are out of cars that have had a warranty job due to headgasket failure and have very oval bores, so are often trash despite the fact they may 'lool' good.

The open deck ej25 block is rated to 450hp and 400ft-lb torque by JUN when used in one of their engine conversions, but bear in mind this will be on good quality fuel.

EJ25 heads work okay, or at least plenty of people have converted 2.5 RS Imprezas with turbocharger kits, although still running the stock compresssion which is low for N/A but high for turbo. Typically the boost run was about 7psi, those running signifcant boost have either uprated the internals or blown the engine, or both but the other way around!

Paul

 

Conrad,

Why would Crawford disagree with me? Are you claiming that he recommends an EJ25 n/a motor over the EJ257!? I know he has a great reputation - but we are not talking about Quirt’s engines on this thread are we?

The ej25 has less deck area and cylinder support then the 257 - why do you think the ej25 will retain its gaskets, while the 257 will not? The liners are the weak link yes, but at least the 257 case supports them better, no?

Craig,

EJ257 can be had for around £1500 depending on source. It has a new semi closed deck case, new rods, new bearings, new pistons, new rings, new seals. It runs a decent c/r and is fully assembled.

EJ25 is second hand I presume? is it phase 1 or 2? - For starters you will need a set of pistons, rings and rods as mentioned (£1000 - 1500). New bearings would be a good idea (£150). At the bare minimum you want to mic the oem crank up and index the motor (new crank £400). Seals/gaskets/machining/balance and assembly (£500 - £1500) . Both the ej257 & ej25 have less than ideal wall strength but the ej25 has less cylinder support then the ej257, so do you fit top hat liners now (£400) or later (£xxxx). With all this done and assembled correctly big power shouldn’t be a problem, the question is, is it worth the expense, time and effort?

For 400hp I would buy the plug in and play version, use your heads and put the rest on a 6 speed. But hell this is scoobynet, why spend £x when you can spend £xx and give yourself a big headache at the same time

 

EJ257 with a new set of forged pistons is where my my money would go. You don't need to split the block to fit the pistons, and the stock rods are much better now (than a few years ago).

Paul

 

Yep, that is good solution for 400+ (or det happy mapping!) If it's a new 257 then no need for any machine work and you can re-use/re-gap the oe rings too.

Craig - did you find out whether it's a Phase 1 or 2?

 

No i didn't and wouldn't know how to, to be honest. I have no eachanical knowledge, only know bit and pieces from reading on these forums.

 

I totally agree with hypoluxa and paul. No harm in doing the pistons if you can afford it, but if you can't, I wouldn't think its a big deal.

If 400 of each reliably is your target, this would be the way I would go.

Going down the ej25 route is prohibitively expensive and as has been said, you are still at the mercy of the head gasket issue.

 

Good luck

Would be tempted to do an EJ22T block to start with for 400bhp.... For ultimate reliability.

Jon.

 

All things are reliable until they go pop, the question is where they go pop.

If the ej257 pops well beyond the limits required, any money spent on a mega strength ej22T is wasted.

 

so what is the limits on a ej257 then

david

 

I think the sensible limit is 400/400, given that I broke 2 of them running est. 10-20% more.

 

So what would be the limitsof the EJ25 then, i know theres the increased cost issue.

 

I cracked a liner on an ej25 that had been closed decked, at 568bhp and 561lbft. I think the american tuning companies are in a better position to comment on at what points they will let go.

the crucial thing is that you don't know the history of a second hand block, which won't be a problem if you have it skimmed and ensure it is square and true. This is a cost you won't need to consider with an ej257.

 

As i mentioned a few posts ago, Jun rate the open deck block to about 450hp/400ft-lb of torque. But that is just the block, they still fitted it with forged pistons and replacement rods, it would have also been running 100 RON fuel.

There are some cheap ways to reinforce the block on the EJ25 that you may want to explore, using inserts press fitted into machined recess' in the deck of the block.

If you're considering putting rods and pistons in an EJ257 anyway, the cost difference between the 2 is quite minimal.

Paul

 

Paul, just because jun rate a block to that much doesn't make it gospel. Especially when talking about a second hand block.

 

True, but they are are happy to sell engine conversions running at that power level, so it should be a good guide.

The EJ257 on the other hand seems to have rather weak pistons (when exposed to extremes of temperature). Only seen one example of an ovalled liner/block with an EJ257, but the potential is certainly there for failure.

I got my EJ25 modified to have a closed deck and it seems to be okay. Adam's original engine he mentions was rather different to mine with less added support.

Either way you should be looking at some pistons, if it's a phase 2 engine, then perhaps get some EJ257 rods to go with some oversized pistons. Those rods would be a good cheap alternative, and available from the likes of Crawford as leftovers from more serious EJ257 builds. If it's a phase 1 engine you will need some custom rods, and possibly pistons to match, as the rod length on the EJ25 is different to EJ257.

Add a set of bearings, some gaskets, and use some EJ20 or the EJ25 heads and you should have something that works.

Paul

 

I am looking to replace the pistons and rods anyway, then get it up and running, power and torque aren't a huge concern, just whether it will hold together. Strength and reliability is the main priority.

 

well you better start making some enquiries then!

Paul

 

if you are going to do that to the ej25 anyway, I would ask paul nicely if he would consider closing the bloc for you using the same method as he did for his own as that seems to be holding together nicely.

Even if your power goals don't push things too far, I would still rather know if is there, especially given the thinner support walls and liners on the ej25, compared with the ej20.

 

Craig, if required the block can be close decked using an insert as Paul has done above, alternatively you can have heavey duty liners installed but if your sticking with the 400/400 target then for the cost involved its not really viable. Speak nicely to Paul and get him to close deck it for you

Conrad

 

can you close deck the ej257 or just the ej25 ? does this help the head gasket problems?

david

 

the 257 is already semi closed.

any closing of the block will provide more material to support the liners and grip the head gasket which should be a good thing.

I think the key to it is making sure that no stresses are put into the block when inserting the liners, as if these free up during load conditions and your block suddenly distorts back to its standard unstressed state, then you will seize a piston.

Pauls has been ok so far, but I wouldn't recommend this as a good idea for those seeking stronger blocks. i would stick with an ej257.

 

that'll be based on your experiences with EJ25 and EJ257 then Adam????

IMHO Pauls is outperforming most of the EJ257's that I know of Just goes to show anything can work if its done correctly

 

Although, correct me if I'm wrong, Paul has also had failed head gaskets on his EJ25

ps Conrad, just because you don't know of them doesn't mean they don't exist....apparently

 

Andy,

LOL,

Conrad,

I think it's fair to say that Adam's had some experience with the EJ25 block, and what happens when a liner cracks from top, to bottom !

Mark.

 

Andy, lol @ dig (again), cant comment on Pauls.....

Mark, I doubt it, he may have bought one but I cant see him being involved in any way other than opening his wallet

 

At least my 'dig' wouldn't break a rib

Andy

 

 

I thought you were being a bit cruel to Adam, read dig in ribs !
I considered my dig at Mark a little more subtle indeed only 22b regulars would even recognise it as such

Andy