Hatch Forged Engine F**ked
 

My Engine died last night, leaving missus stranded in snow storm.
Had the car left running for 5-10 min to warm up, she thought the car sounded a bit different and drove down the road low oil pressure light was on.
Couldn't pull as she was on bad bendy section with no hard shoulder in the snow with cars behind her, had to go a few hundreds meters til road opened up to pull in only for engine to lock up.

I fell sick.... Only forged it 80k kms ago. Car had oil changed at the weekend, had a max 250km done, It was fairly thirsty on oil but not that bad. No signs of oil leaks.
I'll have to check out levels later.
Rang local Subaru garage €1957.84+ 23% vat for Subaru short block and are in stock in the UK.
1 year warranty on block or 2 year warranty if he fits it...

Only put new radiator and Turbo in two weeks ago.

what spec parts are in Subaru short block??
did Subaru address the oil usage issue?

Can't you take back to original forger?
80kms isn't much.

i didn't contact him yet, will call him later. he is 3.5hrs away, Subaru garage 30min.
2 year warranty is on dealer doing removal and fitting.

new turbo? was it mapped for it?

If it were mine I would not be fitting a new 2.5 bottom end

Agree with shreksta,

Further to that, assuming your block isnt scrap and can take a rebore, i'd be rebuilding with new crank if needed, better rods, better pistons, head gaskets and better head studs.

new turbo, was a replacement OE spec turbo
it had:
rcm 11m head stud kit
Omega pistons 99.75mm
K1 Rods
ACL Race bearings
Oild modine
new oil pump
uprated crank shaft
It was mapped after 1000km run in. Conservative map of 310hp / 350lbs

Never tracked or abused, Daily driver 400kms per week
it was a fond of oil.
I was starting to get sick of putting in oil so was thinking standard engine would save the hassle?

it shouldnt have been using loads of oil though, was not right at that point.

Hope you get it back on the road.

was the block closed decked?

How common is it to get more mileage than that from a non factory assembled engine?

depdends on alot of v ariables, but they dont tend to last as long as a non forged

I was told from the horses mouth that my forged effort would last about 60k before needing a refresh or when oil pressure starts to lower , ive done 50k and there is no signs of lower oil pressure and it appears to be in rude health .
Its a bit noisy for the couple of minutes on start up but once warm its sounds like a new engine , maybe the op has had the best of his motor after 80k .
I hope he gets it sorted .

Perhaps it could be oil pick up pipe failure,the 2.5 pick up pipes are known to fracture

I think they all are. Tony on here changes his every time its in the garage.
I've heard the killer b ones are the safety net.

"Could be this!"The spec of your engine build that you have quoted sounds to me that they have used quality parts when it was built,but...saying that it all depends who built it...not every engine builders are equal!.The 2.5 Subaru engine design is prone to failure thats why so much of them break and the owners have to go through the expense of a rebuild.Even when my mate was telling me that he was looking at getting a 2.5 Impreza and asked me for my advice I told him if its definitely a hatch Impreza that he is looking for,to make sure that he buys a JDM 2.0 litre or budgets in for a rebuild if its a 2.5 or "C' buys a forged 2.5 and hopes for the best,even in the Subaru manufacturing plant in Gunma Japan any special edition or racing Subaru engine they build is with a 2.0 litre block that should tell you everything that you need to know really about those engines..2.5 engines can be built to last but in my opinion not like the Subaru 2.0 litre,the 2.5 needs to be built by an engine builder that knows exactly what he is doing.SJ.

Can someone explain how/why does a forged built engine have a shorter life expectancy than a std engine?

Assuming normal/std running ( ignoring usual hg & ringland failure) and one has std pistons and one forged why does the forged one have such a reduced life expectancy?

Or is the reduced usage on forged due to it generally expected to be pushed to higher performance and therefore more stressing?

Because there is more wear when cold ie piston slap

Engines that are forged 9 times out of 10 are built for strength so as to produce more power i.e...go faster and will have a much harder life then a standard engine that the factory has built for reliability and longevity and will be driven at the factory tolerances...but saying all of that though forged engines can last as long as they were built professionally in the first place, and with strict regular maintenance and some mechanical sympathy and intelligence when in use.Their are quite a few members on here thats running a Subaru with 600+bhp myself included that has been at that power now for years.SJ.

This probably isn't the case as this engine has relatively high mileage before failure. But there's silicone sealant in a lot of of places in a Subaru engine. At work we have robots which apply the sealant and it's very difficult, almost impossible, to apply it with the same precision by hand. I would assume the Subaru plant uses robots too. If too much sealant is used you could partially or fully block oil passages which adds another risk of failure. But that would probably have shown up long before.

So the longevity will be very dependent of who's the engine builder, to be fair this sounds like a pretty decent one. I know it's feels like crap to have the engine fail again but I doubt the forged engine I have in my car will even last 20% the mileage of yours. Maybe I'll go for the factory EJ207 V7 STI block instead. I think it will be better for a road car with less piston slap and less blow-by .

I don't know if the pistons in the USDM Type RA EJ257 will last good enough, they are upgraded though
https://importcarparts.co.uk/parts-i...y=&searchPart=

No, was standard block

every 40K rebuild, no thanks i take my chances on stock engine and not tune it up at that rate.

Oil pick up failure, hadnt heard of that before. Will have to check.

My Insurance is up for renewal, i think its time to put on the no claim discount protection on. Give it 2 weeks and then see
will my insurance cover the cost of a new Subaru short block and get local Subaru garage to install it and get the two year warranty.
it wont effect next years renewals cost either. Its the cheapest way out.....

I second the call for oil pickup failure.

To whoever it was that said a forged engine will only last 40k miles max. :facepalm: What tosh.

As already stated the cold startup is where wear can occur due to the expansion of metals and the process forged or cast. Forged pistons have a greater thermal expansion so when cold they slap and wear. As cast don't expand as much then the cold tighter tolerances reduce this wear. A forged daily driver would suffer more than cast for this reason, race cars don't get started everyday. The other reasons because it IS forged and they will get abused more, quality control is a thing in an OEM engine, forged is down to the knowledge/skill of the engine builder.

So it's not the piston rings that seat on the bores in a forged engine then like a normal engine? Are you honestly suggesting the pistons are rattling around damaging the bores in a forged engine?

What a load of total b0llocks your theory above is. I've never heard such tosh.

You would expect a forged engine to last every bit as long as a standard engine if not longer.

Good grief.

Probably best not to have posted this entire thread in that case!


Some confusion though, you mean it’s done 80,000 kms since rebuild, yes? Just someone quoted you saying 80 kms. To be honest that’s about 4 times as far as the average 2.5 lol

Sadly driving it that far with the oil light on and until it seized up I’d imagine a right mess of metal debris everywhere.

Wooow hold on steady. I did not say this is why, I said wear CAN occur. If the thermal expansion is not calculated by the engine builder it could lower the life expectancy is what I am implying. I am sure there are many examples of forged engines that can do/have as many miles as OEM.

Go on. Then, please divulge if you will.

How can a forged engine have increased wear over a standard engine?

Ok why do wiseco coat their piston skirts? , as I have in my car.