Just planted the seed now watch it grow lol...

Having recently bought a hatch wrx and then started reading all the disaster stories of the 2.5 pistons, i obviously avoided telling the wife about the problem as its her daily driver while i work away and (She did not want another scooby!)   

But now she has fell for the car, i sent a couple of P.Ms to Andy Kindon, (who seems very helpful by the way!) i have decided to get the problem sorted before the big bang.  

Any way I am away for at least another month but am looking at getting it done next time i am home so today i dropped the bomb on the wife!   

Basically it went like this, "Natalie i am getting worried about that car we bought, been reading loads of horror stories on the net about engine failures it could happen any minute whilst you are driving! blah blah blah" So now she is shitting herself that its going to pop but unknown to her next week i will have chatted with a  very helpful mechanic (Andy Kindon) who will fix it and make it all safe for her lol.....

Any way thats the plan then i will have to stop spending cash on it for a couple of months after the build to let her settle down. Then hit her with a turbo front mount and remap  

Nicely done young man   

Like ur style mate

Hope I see her about cotta il say he's full of shit there's nowt wrong with them..

Can't beat a spanner in the works

Few pints for me should sort the problem when your back hahaha

That could back fire, you could come home and find she has swapped it for a focus    

Or she could do some googling and find this thread    

Well done. Well I got good new from my wife yesterday said can do wat I want once cars forged.

Hey hey big thumbs up

I have already got my mate to start dropping hints that the engines are shite he was round mine yesterday looking at my new exhaust 

byers wrote:

Hope I see her about cotta il say he's full of shit there's nowt wrong with them..

Can't beat a spanner in the works

Few pints for me should sort the problem when your back hahaha

Byers you cant handle a few pints, i will get you a fruit shoot at the next meet  

Nunu wrote:

Well done.  Well I got good new from my wife yesterday said can do wat I want once cars forged.  

Hey hey big thumbs up

I will defo have to wait a while before splashing more cash.

What you looking at doing to yours once its forged?

Jonny Gav wrote:

That could back fire, you could come home and find she has swapped it for a focus    

Funny enough i bought her a Focus about a month before i bought myself the impreza but once she drove the impreza she wanted rid of the Focus   

wrx doesn't have piston issues ! its just sti if I remember rightly

Yeah thats what i thought to sparkey

lol very cool like it

The WRX 2.5 uses the same high silicon pistons as the sti so as soon as you start putting a bit power through it, it will have issues.

From reading up on other forums all the 2.5s have issues its like a lottery who's goes at what mileage and lots of different views on why, but the hatch 330s seem to be the worst!

carl08 wrote:

From reading up on other forums all the 2.5s have issues its like a lottery who's goes at what mileage and lots of different views on why, but the hatch 330s seem to be the worst!

I think this is due to the map they are running?

Jonny Gav wrote:

The WRX 2.5 uses the same high silicon pistons as the sti so as soon as you start putting a bit power through it, it will have issues.

Yep apparently from what i have read these high silicon pistons are good but they cant handle any det whatsoever so buy the time the ecu reacts to the det the damage is done!

yep john ive not heard of wrx having any problems

mainly sti & afew 330s

That's cos there aren't many higher powered WRX's, at a standard 227hp and a TD04 turbo the pistons are well within there design limits.

When you get up into the 300's the extra heat generated seems to overload the pistons, god knows why subaru chose to use such a right tolerance, most likely to do with emissions, think they decided to use a high silicon alloy as it has less swell than a more ductile alloy, the downside is the high silicon alloy is brittle, any swell caused by heat will result in piston to bore contact, the smallest area on the piston is the portion between the rings (ring land) if this contacts the bore it will snap.

Using a more ductile material and a larger clearance will prevent this from happening, problem is from an emissions point of view, when the engine is cold it will pass more oil and gasses past the rings, they are quite noisy when cold too (piston slap) so the avarage car buyer would think the engine sound rough and complain as owners did in 1998 when the V4 Impreza was launched.

Catch 22 really.

Jonny Gav wrote:

That's cos there aren't many higher powered WRX's, at a standard 227hp and a TD04 turbo the pistons are well within there design limits.

When you get up into the 300's the extra heat generated seems to overload the pistons, god knows why subaru chose to use such a right tolerance, most likely to do with emissions, think they decided to use a high silicon alloy as it has less swell than a more ductile alloy, the downside is the high silicon alloy is brittle, any swell caused by heat will result in piston to bore contact, the smallest area on the piston is the portion between the rings (ring land) if this contacts the bore it will snap.

Using a more ductile material and a larger clearance will prevent this from happening, problem is from an emissions point of view, when the engine is cold it will pass more oil and gasses past the rings, they are quite noisy when cold too (piston slap) so the avarage car buyer would think the engine sound rough and complain as owners did in 1998 when the V4 Impreza was launched.

Catch 22 really.

This sums up a lot of reading in a simple post   (BUT)-
I am no impreza expert but i have been reading a lot about other 2.5 failures, and also a lot of experts opinions (which do differ bye the way).
To be honest it still seems like a lotto as some people blame, fuel, oil, high revs etc. But each case of failure is different.
Standard looked after car 10000 miles pop! Mistreated car 80000 no probs  
Lots of complaints to Subaru but no liability accepted  

fookin horrible noise piston slap mines loud till warm hate it

carl08 wrote:

Jonny Gav wrote:

That's cos there aren't many higher powered WRX's, at a standard 227hp and a TD04 turbo the pistons are well within there design limits.

When you get up into the 300's the extra heat generated seems to overload the pistons, god knows why subaru chose to use such a right tolerance, most likely to do with emissions, think they decided to use a high silicon alloy as it has less swell than a more ductile alloy, the downside is the high silicon alloy is brittle, any swell caused by heat will result in piston to bore contact, the smallest area on the piston is the portion between the rings (ring land) if this contacts the bore it will snap.

Using a more ductile material and a larger clearance will prevent this from happening, problem is from an emissions point of view, when the engine is cold it will pass more oil and gasses past the rings, they are quite noisy when cold too (piston slap) so the avarage car buyer would think the engine sound rough and complain as owners did in 1998 when the V4 Impreza was launched.

Catch 22 really.

This sums up a lot of reading in a simple post   (BUT)-
I am no impreza expert but i have been reading a lot about other 2.5 failures, and also a lot of experts opinions (which do differ bye the way).
To be honest it still seems like a lotto as some people blame, fuel, oil, high revs etc. But each case of failure is different.
Standard looked after car 10000 miles pop! Mistreated car 80000 no probs  
Lots of complaints to Subaru but no liability accepted  

It isn't a complicated subject, it's simple mechanical engineering, remember all machined and cast parts have engineering limits around them, the bore will have a minimum and maximum tolerance and so will the piston, if you get the piston diameter on the top end of the spec and the bore on the bottom end it will be more likely to fail over an engine with the piston at bottom end and the bore at top end of the tolerances.
That is before you bring roundness and concentricity into the equation, I deal with this type of problem with bore castings all the time at work.

Me too, Friday engineering at its best,

I can lend u a smoke grenade lol