Originally Posted by thenewgalaxy

David (or anyone else who builds these things for a living), one thing I struggle to understand is that the pistons in the 2.5 are made of the same material as those in the 2.0 cars post-2003.

I've got a friend who absolutely spanked the **** off one of these engines for several years, tracked it and all sorts - and it was pushing out over 450bhp.

I've also seen and heard of so many of these 2.0 cars "in the wrong hands" with decats and cone air filters, ones thrashed from cold and run on 95 RON - you name it. They keep going.

I don't worry too much about mine as it was built by Cosworth and would expect it to be okay for that, time will tell. But it all seems a bit unnecessary to throw so many expensive and supposedly high-tolerance bits at an engine to achieve 400/400 when a remap and turbo is sometimes enough on the older cars, albeit very "reliably" too.

I understand that with the 2.5s the head gaskets might not be up to the job or bolted down hard enough and that the map may cause issues with det or whatever, but surely there is something else responsible for the pistons breaking?

What I'm basically asking is, do you think that solving the problem could be as simple as changing the way the engine is assembled without altering any internals? Or is there some fundamental issue with the shape or structure of the engine that requires new bits?

Originally Posted by Carnut

, BMW and VW ranked in the bottom 10 of a study into engine reliability

German-made cars are not as reliable as many believe, according to new research. Warranty Direct has studied its claims data to compile a list of the manufacturers with the most reliable engines - and*Audi,*BMW*and*Volkswagen*all finished in the bottom 10 out of a total 36 makers.In fact, the only firm whose cars had a worse engine failure rate than Audi was MG Rover.*MINI*wasn’t much better, finishing third from bottom, while its parent company BMW came seventh from bottom. And, despite its reputation for rock-solid reliability,*Volkswagen*came ninth from bottom.Honda*scooped the gold medal – the study found that just one in every 344 Honda engines failed, compared to one in every 27 Audi engines. Despite its recent recall woes,*Toyota*came second and*Mercedes*managed to outperform its fellow German brands with a respectable third-place finish.Duncan McClure, Warranty Direct Managing Director, said that engine failures are the worst for motorists as they’re the repairs that can lead to the highest costs because of the parts and hours of labour required to fix them: “The nuber of failures may be low compared to areas such as axle and suspension damage but engine repairs almost always result in costs reaching the thousands for motorists who aren’t covered by a warranty.”An engine failure on a*Range Rover*Vogue recently led to Warranty Direct’s highest ever claim of £13,000.

In 2011, a class action lawsuit was filed in United States District Court in New Jersey against Daimler AG, Mercedes-Benz, Mercedes-AMG for alleged defects in the M156 engine contained in AMG vehicles built in 2007-2011 model years leading to premature wear. The plaintiff claimed the combination of cast nodular iron camshafts and 9310 grade steel valve lifters contributed to the premature wear, but the defendants had known about the defect since 2007.[2]

http://www.pswlaw.com/Notable-Cases/...ss-Action.aspx

Honda being the most reliable engine manufacturer has 1 in 344 engine failures.

Originally Posted by APIDavid

Essentially the piston material is not strong enough to resist the explosion of the fuel air mix and it sets up a rattle/vibration that shakes the piston to bits harmonically. More so if the timing or A'f ratio is a bit off. Rather like an opera singer hitting a high note and breaking a wine glass.

That is a very simplified explanation.

There is no different way to build the engine when substandard components are being used.

I have always said that you can build a Subaru engine with NASA moonrocket quality parts - but detonation, excessive in cylinder temps, or high oil temperature will ruin it no matter what.

Taken as a problem on a worldwide scale, the numbers of failures seem high to us, but are in fact, globally, the failures are not enough to justify Subaru putting better pistons in ALL engines sold worldwide, it changes their cost equation too much. In my opinion.

David

Originally Posted by Shaun

Someone best amend the thread title.... reports from the US of 2015 STI failures due to bearings on No.3 rod failure. Could very well be isolated, but at least three have been reported in the wild thus far.

Originally Posted by Shaun

Someone best amend the thread title.... reports from the US of 2015 STI failures due to bearings on No.3 rod failure. Could very well be isolated, but at least three have been reported in the wild thus far.

Originally Posted by honeybadger

haha

Originally Posted by Shaun

Someone best amend the thread title.... reports from the US of 2015 STI failures due to bearings on No.3 rod failure. Could very well be isolated, but at least three have been reported in the wild thus far.

Originally Posted by Seahound007

You cruel cruel Badger.

Originally Posted by honeybadger

at this point is there anything else to do, but laugh at Subaru engine failures?

it's better to laugh than to cry

which breaks more? an Alfa Romeo or a Subaru 2.5 turbo? maybe we should do an opinion poll?

Originally Posted by Seahound007

If Subaru lost that contest I would throw my claw in and hide in my tent.

Originally Posted by thenewgalaxy

Thanks for your reply David.

I find it quite amazing the hypereutectic pistons in the 2.5 aren't up to the job, but the same hypereutectic ones are in the 2.0 are (or at least more so, up to regular power outputs or higher).

So it would appear the material is not up to the job because the stresses (e.g. explosions caused by injection of fuel and air into the cylinder) in the 2.5 are different in some way to the 2.0?

After what I saw on the evening news I'm not entirely sure an engine built from spaceship parts would get very far at all

Originally Posted by Seahound007

Just remember no one comes on this site & says had a drive around today and car was fine.
Also no one says my engine blew up today. Maybe it was that dodgy remap I had done / petrol I bought from the local garage that hasn't had a petrol delivery since 1957/cheap non spec oil I used/or I had been thrashing it round a track for 27 hours just before it blew up.

Originally Posted by Seahound007

Just remember no one comes on this site & says had a drive around today and car was fine.
Also no one says my engine blew up today. Maybe it was that dodgy remap I had done / petrol I bought from the local garage that hasn't had a petrol delivery since 1957/cheap non spec oil I used/or I had been thrashing it round a track for 27 hours just before it blew up.

Originally Posted by urban

Like this?

Originally Posted by thenewgalaxy

To be honest this thread should include 2.5 Hawks too, my Spec D blew up.

Originally Posted by lordharding

Might as well add the deasels to the ongoing Subaru list of chocolate engines

Originally Posted by APIDavid

Yep, Chocolate cranks in 57,08 & 58 plate diesels. They snap in half - [ more or less ] and then in the tangle break the cylinder block, so it is wrecked.

A short motor from Subaru UK is about 4 grand + VAT Plus 600 + VAT for gaskets. We always fit chains too, as they are known to strech when the engine tries to stop or start when all inside is mush.

Unlikely with labour to get away with a bill much less that £5000 + VAT to fix a diesel. We've done a number of them and I bought a couple that sounded cheap with busted engines that turned to be wrecked and even I could not fix them cheaply.

Don't let anyone, if you need an engine , tell you they are importing the engines from Japan. To my knowledge the diesel 2.0 turbo is not sold in Japan.

David

PS if you own one DO NOT miss aservice or delay servicing the car as IM will drop you like a ton of bricks if they can.

Originally Posted by APIDavid

PS if you own one DO NOT miss aservice or delay servicing the car as IM will drop you like a ton of bricks if they can.

Originally Posted by APIDavid

Yep, Chocolate cranks in 57,08 & 58 plate diesels. They snap in half - [ more or less ] and then in the tangle break the cylinder block, so it is wrecked.

A short motor from Subaru UK is about £4 grand + VAT Plus £600.00 + VAT for gaskets. We always fit chains too, as they are known to stretch when the engine tries to stop or start when all inside is mush.

Unlikely with labour to get away with a bill much less that £5000 + VAT to fix a diesel. We've done a number of them and I bought a couple that sounded cheap with busted engines that turned to be wrecked and even I could not fix them cheaply.

Don't let anyone, if you need an engine , tell you they are importing the engines from Japan. To my knowledge the diesel 2.0 turbo is not sold in Japan.

David

PS if you own one DO NOT miss aservice or delay servicing the car as IM will drop you like a ton of bricks if they can.

Originally Posted by T5NYW

My 2.5 2011 with 19kmiles and 34months a full engine was more closer to £9+k and Subaru UK footed the bid thankfully

But as the remainder of 3 year warranty would only have been max 1 month I paid nearly £1K for forged Pistons to be fitted. Although Pistons weren't at fault

Tony

Originally Posted by thenewgalaxy

It remains the only UK 2011 car I know of Tony. Engine problems or not you appear to have been pretty unlucky.

Do you still have the car?

Originally Posted by thenewgalaxy

Thanks for your reply David.

I find it quite amazing the hypereutectic pistons in the 2.5 aren't up to the job, but the same hypereutectic ones are in the 2.0 are (or at least more so, up to regular power outputs or higher).

So it would appear the material is not up to the job because the stresses (e.g. explosions caused by injection of fuel and air into the cylinder) in the 2.5 are different in some way to the 2.0?

After what I saw on the evening news I'm not entirely sure an engine built from spaceship parts would get very far at all

Originally Posted by DTVHSR

They changed to this new material with the 2.5 engine, they never used these pistons in the 2.0's.

Hypereutectic Pistons made for quite an interesting read. Shame Subaru ended up with such an unreliable set up from them though.