Tuesday, 10 November 2009


Hello all,
Now here is a dilemma subaru big end knock or faliure how much to re build a wrx engine

This is very common on subaru's
I am writing this to pass on my experience

I have a 2001 subaru wrx with full service history been done every 5000 miles some at 3000 miles by subaru main dealer and wondered how the hell i had big end faliure! at 68000miles

Now from my research i have found a few interesting facts from different people and subaru whilst on my search for new parts this is shocking!

Ok how much does it cost for an engine re-build ?

You wont get any change out of £3500.00 and thats just bottom end you are looking at £500 for a crank and there is two different types, rear thrust and centre thrust, centre thrust is generally post 2001 dont hold me to this.
£340 for genuine gasket set not including rocker cover gasket at £80 plus vat now thats not cheap
also big end bearings £59 set and main bearings at £89 and some one good enough to take it apart and re build it

You cannot re grind a subaru crank whatsoever

Do not let anyone tell you you can as the crank itself has ball bearings in and the grinding swarf will stay in the oil wells untill you fire it up and bang, this has happened !!!
i have heard stories of people that have spent £4500 on a build and its gone wrong!
be warned !!!!!!!!!!!!!!!

Now you think thats bad once the heads are off you will see between valve seats and spark plug hole will be hair line cracks this is very common on subarus where to go from here is your own choice.

you will need to change the oil pump and water pump as its all around the cambelt area and oil pump is blamed for subaru engine faliure

I will tell you what i have been told by a subaru engine builder take it as you wish
he told me that if you get the engine management light on it can sometimes lead to a misfire at high revs and his words its a common thing on subarus a duff or knackered sensor can take the engine with it.

This may seem daft but when mine went i had the engine management light on and split second after started knocking at bottom end apparently a misfire can send a wrong signal to spark plug and detonate at the wrong time causing lightning bolt force on con rod and tempoarily starving crankshaft of oil and bang

The cheapest way is to get a second hand engine from a breaker with warranty as some do.
with low mileage and do a swap unless you have a kings ransom in your purse and go for a no expence spared genuine subaru or cosworth build

however i would not suggest revving up to the red line or bouncing off the limiter 5600rpm is enough to preserve your engine and still go some as turbo starts to fade unless you have been mucking around with waste gate and bigger turbos

Thanks for reading sorry to go on but thought i would pass this on this is information based on my experience do not believe everything you read on the internet feel free to add any comments

1 comment:

  1. Would like to weigh in here with some info.
    Any uk classic impreza made before 97/98 will be a centre thrust bearing. After that it became end thrust.
    Hairline cracks on the head??? Not all have that issue.
    Yes oil pump gets the blame most the time. But from experience I fail to see how that is, unless the simplicity of the pump means the internals would have chewed up.
    My personal experience is that there are too many people that jump in and drive car hard and fast from cold. That's never good for any engine as it's too much stress.
    I also find on all I have rebuilt it's piston number 2 that takes the most crap and fails first.