MadUsa1

I've just had a search for rod failures on the 2.5L and I couldn't find ANY.

We all know about the ringland and headgasket issues on the 2.5 but I've never read about rods going.

If that's the case, why does everyone go out and fit 800bhp H section rods to these engines when they get them rebuilt?

In fact, the same could be said for the entire bottom end - has ANYONE ever spun a bearing on a 2.5L??

Surely the solution to reliability with these engines is a set of drop-in standard sized forged pistons, a decent set of head gaskets and some uprated 11mm head studs.

Why all the £10k engine builds?

tubbytommy

iTrader: (20)

no head gasket issues,its all lies ask chopperman
sounds like an unusual failure though.

merlin24

iTrader: (1)

Lots of spun and coppered big end bearings on the EJ257 and have seen a few failed rods(bolt failure) normally due to over boosting or mechanically over-revving thrown through the crancases.
The bolt type rods are a vast improvement over the earlier 'nut' type rods but Yes,they still fail and thats why most people go for decent steel rods while the engine is apart.

Mick

MadUsa1

Good to know, were these all 2008 era EJ257's by any chance?

Out of interest, are the rods, rod bolts and bearings used on the 2.5L the same as those used on the newage 2.0L engines?

chopperman

Where did i say it never happens?
Troll all you like mate, im too long in the tooth to be bothered by it ! I just point out its not as common as some of you make out. In fact i think its market manipulation. If you post and re-post enough you will turn the masses against the 2.5 in an attempt to push up the value of your knocking bottom end 2 litre's I don't think many are fooled by your finger pointing at me. I've been pretty consistent in my opinions

tubbytommy

iTrader: (20)

calm down dear its only a bit of banter.

chopperman

There there tubby, no need to cry. Im sure im not the first to catch you out !

MadUsa1

When you say "over boosting" what exactly do you mean - simply asking the engine to cope with too much boost?

chopperman

The way to kill your rods is by missing gears and revving to the limiter while the engine is not under load. The piston accelerates up the bore to fast stretchering the rod . This can cause bearing failure or the rod to snap.

Alan Jeffery

Sorry, but the fact that you've never heard of it doesn't mean it isn't happening.
Any engine can spin a bearing if it has any kind of oil pressure issue. 2.5's included of course. Subarus are particularly prone to it, having little margin for error. We have seen the effect of an actual rod fracture on a 2.5.
If you're only going to run the standard power output, the standard components are fine, although I'd rather go for forged pistons and have done with.

If you're thinking of modifying your car, I'll put it this way;
There you are, standing on the dizzyingly high bridge during your New Zealand holiday.
You've decided to try bungee jumping.
You can have the ordinary rope, or pay just a bit extra for the really strong one.
What's your choice?

MadUsa1

Thanks for the reply Alan.

What was the cause of the rod failure you've seen on the 2.5L?

I don't doubt that (some) uprated rods and bearings are less likely to fail than the standard items, it's just that these don't seem to get mentioned as common failure items on the 2.5L. Of course, if you have oil pressure issues there's a risk of bearing failure - this goes for the standard bearings and any uprated items.

Many people say the EJ257 block is simply not capable of safely handling more than 420 / 450. Fitting uprated rods and bearings will make the bottom end stronger, but if the block is still the weakest link, what's the point?

To follow your analogy:

If the week point is the rope, then you should definitely change the rope. That'd be like the pistons, HG and head studs on the 2.5L. However, since the wooden platform used to launch the bungee is more than capable of supporting the jump, why bother to upgrade it to an expensive, cosworth-branded steel platform?

Tidgy

Comapnies dont tend to go round advertising that something has broken, if you dont hear many then it sugests its not very common, however, that doesn't mean it doesn;t ever happen.

A certain company claim they have never had an engine fail, yet i know personaly 1 person who's has and the car wasn't even modified.

MadUsa1

I disagree - companies selling uprated conrods and bearings would have a very strong incentive to advertise failures of the OE rods and bearings, and yet you never really hear about it.

You talking about RCM?

MadUsa1

I understand that all newage STIs use the same rods and bearings.

All STIs meaning JDM, UKDM, 2.0, 2.5L, Spec C, etc.

I understand the Classics all used the same rods as well. The classics had the nut & bolt design and the newage upgraded to a (stronger) captive nut.

Can someone confirm this?

stevie1982

iTrader: (16)

dude let it go, nearly every time i see a post regarding new-age or the 2.5 block you straight up bring this fella out and see you posting the same comment lol, there is banter and then this you two need to kiss and get it out of the way

Alan Jeffery

In the particular instance we saw, I'd put it down as an over rev, or even possibly a flawed rod casting. It was clearly stress fractured, with no bearing failure.
Going back some years, H beam rods were a costly option, but not so much now, and considering the cost of tearing an engine down, it isn't a deal breaker these days.
We've run the stock EJ257 block at over 600 bhp. We've never seen an actual block failure from any engine we've built.

Er, if the weak point is the rope, I'd change the rope!
And if I was going bungee jumping, I'd want a steel platform, decent rope, air bags, a crash helmet, parachute and a padded codpiece filled with lucky heather...

MadUsa1

Oh bollock. I meant "should change the rope" not "shouldn't" ! :-)

Can you confirm that all new age rods and bearings are the same?

Alan Jeffery

I've learnt not to use sweeping statements like "all" for anything!

MadUsa1

Fair enough, but in general the rods and bearings are more or less the same for all new age motors? Seems that way from the RCM website.

My point is that there are plenty of standard newage 2.0L engines running well into the 400's with no problems, so with forged pistons, decent head gaskets and uprated headstuds, there's no reason the rods or bearings should give any issues on the 2.5.

Of course, if you over-rev the engine and don't keep an eye on lubrication you might run into trouble, but that goes for the 2.0 as well as the 2.5

chopperman

Are STi rods stronger than wrx rods ?

Alan Jeffery

Yes, but the fact of performance tuning makes an over rev more likely.
The bearings we choose to use are the same for all Impreza engines.
We have established formulae that appear to work well. If any customer would like to deviate from that on cost grounds we don't mind at all.
As long as we all know where we are that is.

MadUsa1

I was talking about the OE bearings fitted by subaru - are they all the same or do they have different bearings for the JDMs or Spec C cars?

Alan Jeffery

We only use ACL Race.
We have no way of knowing which precise combination of materials Subaru choose.

MadUsa1

Anyone else know?

Are all Newage conrods & bearings the same?

Or did the JDMs / Spec Cs get better equipment as usual?