willysink

hi guys, the bearings have gone in my sti 7 for the 3rd time!!!!
number 1 and 4 conrod bearings are wrecked!!
it must be an oil problem, i have an oil pressure gauge and it was showing very good oil pressure until the point of failure, it was showing between 4 and 6 bar when hot!
i had the crank shaft reground the last time the bearings went, but was recently told you can't regrind impreza cranks as the oil ways get blocked, although i poured oil into the oil feeds on the crank and it flowed out the bearing feeds freely!!
any ideas on what could be causing the bearings to fail??
i also fitted a high flow oil pump at the last rebuild!

STI_Baly

iTrader: (23)

Did you use standard size bearings after the crank regrind? And do you know what the clearances were on the last build?

Plus do you know why your bearings failed the first time? and just why was the crank ground?

STI_Baly

iTrader: (23)

Oh and if you have any pics of the big end bearings it would help.

m@t STImulation

iTrader: (3)

as people have said b4 same modine etc

fastmike

iTrader: (4)

the oilways dont get blocked........ you cant clean the grinding dust out of them .. and then you get bearing failure again

fastmike

iTrader: (4)

Yep..... and that too if its the same modine

JohnD

iTrader: (5)

It's not the possibility of blocked oilways that's the problem when re-grinding Subaru cranks, it's that you grind away the surface hardening which, like many other makes, is extremely thin. This is not a cheapskate method, but an effective way of achieving a wear resistant surface.

JohnD

TheVoices

iTrader: (5)

I have had some experience of bearing failure.

I was told not to get the crank reground due to the metal particles left behind in the oilways, no one will guarantee that their cleaning method will remove all the bits.

I have heard the other explaination about surface hardening before but the Subaru workshop manual (as used at dealerships) quotes 0.25 as a maximum regrinding limit ?

So tends to suggest that Subaru themselves don't have an issue with regrinding ?

JohnD

iTrader: (5)

It must be achievable, after all, the mains and big ends are ground to finish in production!

JohnD

TheVoices

iTrader: (5)

Plenty of people willing to regrind the crank, no one willing to guarantee removal of all the swarf !

I bought a new crank rather than risk it !

TimH

iTrader: (11)

I believe the issue is that the Subaru crank has non-removable oilway plugs. With most cranks you can remove the plugs and clean the oilways out then refit the plugs, but you can't do that with the Subaru one. So you cannot guarantee that it's been cleaned out properly after a regrind (or, indeed, after bearing failure etc).

handsome rob

Hi, what sort of milage did you have on the clock first time it went ? i've got a version 8 sti , had it 2.5 years now showing 64k, since joining SN im starting to worry the engines are fragile ? im wondering if im going to be in the s--t big time with the wife over the next 10/15 k ?

Splitpin

The problem with places like this is that people who've got problems tend to post here, which can lead you to draw conclusions like that. What you don't see are the thousands of drivers who rag their cars every day and put huge mileages on them. If these engines were inherently "fragile" they wouldn't handle folk running big power through them reliably - but they do, as you'll also read about here.

She's a woman, and you're married to her, so chances are you'll be in the sh*t sooner or later no matter what. Whether your car has anything to do with it remains to be seen so why worry about it in the meantime?

But to answer your point, if your car's running fine at the moment, there's no obvious reason to think why it'll suddenly expire.