Early Christmas Present from Subau (new short motor)

[metalcar]

Well,

I went for a drive with some mates on Sunday. Trying to clear out the cobwebs and well, it seems my big end bearing really didn't feel like it or something. After about two hours of driving up and down hills, it gave way and starting making some really awefull noises. After hours on the side of the road and the friendly warning of my engine was f*cked. It went on a tow truck with an overnight stay before getting to subaru toowong.

On the monday I managed to get a loan car and the promise they would look at it and let me know what was up.

Tuesday I get a call, telling me the big end bearing was gone and I needed a new short motor and remachined heads. This is normally something like $7500 and with my car having done 88000kms and out of manufacture waranty I was starting to fear the worst.

Subaru Australia however has come to the party and will be proving all the parts due to my service history. So not very happy that I"ll be out of the GT for a few weeks, but its not going to cost me much in the end (only labour) and I will have a new engine almost.

Only problem is I will need to worry about running the thing in once I get it back. Any tips for that? Its a MY05 GT so everything else is well and truely run in.

[Q]

I had exactly the same problem when my car had about 30000klms on it. Big end bearing let go leaving me stranded on the side of the road. Took 3 months to get it back from Subaru but thats another story.

re: running it in, rev it from the beginning and don't be gentle. The one thing you shouldn't do is load the engine, like doing 60kmh in 4th or 5th then putting your foot to the floor, this puts massive pressure on everything and can break things real quick. Also don't sit at constant revs or use cruise control for a while, just accelerate then back off and repeat. This lets the pistons/rings expand then contract and creates a good seal in the bores.

Flog it from the beginning, that will seat the rings properly and you will have a sweet running boxer that should last a little longer than your other one! Mine's up to 110000klms now with no worries, uses no oil at all and produces good power

If you are gentle with running it in you will only glaze the bores and end up with a slug of an engine that uses oil. Speaking of oil make sure Subaru fill it with mineral oil and not the usual synthetic, this is really important. Also I changed my oil twice within 200klms of getting the car back just to make sure there were no nasties floating around my sump from the build and the running in process. Up to you if you think that is necessary.

This is of course just my opinion and how you choose to do it is entirely up to you

[smythie]

sounds like pretty sound advice going from all of the reading I have found and been directed to over the years

[metalcar]

Cheers for the replies guys.

That fits with what I've read before, just couldn't find the threads to confirm it. The other bit is how many ks should I worry about it for before being able to go back to 'driving as normal'

Just having to wait it out... The outback they've given me is nice, but except for the leather seats its pretty much the direct opposite of my car I'll probably get used to it just in time to had it back.

[Ric]

It's the first 100km that is most important.
You need to cinstantly keep it on power, letting the revs rise, but not over-revving (hitting the rev limiter is a definite no-no!)
Also, do NOT use engine braking to slow down in the first 100km, particularly if it is manual.

[Q]

Wondering WHY it is bad to use engine braking?

[Ric]

The explanation the Subaru mechanic gave me was that you want to maintain positive pressure inside the cylinder to get the correct wear on the rings.
Engine braking causes generates negative pressure (i.e. a vacuum).

[Spec B Wgn]

have a read of this technique on how to run a motor in..

http://www.mototuneusa.com/break_in_secrets.htm

its well worth the read... trust me

[Q]

The explanation the Subaru mechanic gave me was that you want to maintain positive pressure inside the cylinder to get the correct wear on the rings.
Engine braking causes generates negative pressure (i.e. a vacuum).

I disagree with that info. The negative pressure on deceleration is necessary to remove any debris and exit it thru the exhaust so the piston can have a clean run the next time. The link by spec b wgn is pretty much spot on imo.

[jdm rsk]

have a read of this technique on how to run a motor in..

http://www.mototuneusa.com/break_in_secrets.htm

its well worth the read... trust me

yeap my mate does track days in japan both bikes and cars and uses that guys method and he swears by it.....

[metalcar]

thanks for all the tips guys.

Looks like I'll be running the method linked.

Still waiting on the car though... Short motor still hasn't arrived so I figure even if it shows tomorrow I'm up another week

[metalcar]

Well it looks like its going to be more valentines day then Christmas.

But it turns out I need new VVT gears and a Turbo too. Still all covered, but a second stint of waiting for a backorder from Japan so still got ages to go...

C'mon Subie, C'mon C'mon.