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-   -   WRX 2.0 rebuild (http://www.wrxtuners.com/forums/f103/wrx-2-0-rebuild-31975/)

flewthecoupe 01-30-2012 11:41 AM

WRX 2.0 rebuild
 
Ok, I'm not a newbie to rebuilding engines... if they are the V or inline versions. Never rebuilt a flat 4 and can't imagine it's much different.

My step son spun 2 rod bearings, 1 and 4. Not much for metal shavings throughout that I could see upon initial inspection but that only included the bottom of the pan, and the oil pick up screen.

The engine has not been pulled yet and I still have to look at and/or measure the cylinder walls, pistons, rings, ring clearances, cranks shaft journals, connecting rods, etc.

I know we can reuse headbolts and block through bolts, etc.

So here is my question, assuming I measure and tolerences come back as still within specs, is there anything aside from rod bearings, main bearings, and a complete gasket set that I should consider replacing on this motor?

It has +/-76,000 miles on it. He has limited funds to work with. Again, assuming much without pulling the engine, I can pull it, boil it, turn the crank, get oversized bearings, replace all gaskets, and update the oil pickup for about $800.

Minumum on a shortblock that I've found is about $1650 and that doesn't include a master gasket set for $250ish plus an upgraded pickup for about the same.


Any thoughts would be much appreciated.

Thank you in advance,
Michael

brfatal 01-30-2012 01:47 PM

I don't really recommend making cost estimates without having even torn it apart to inspect the damage. For example, near every spun bearing I've ever seen has caused head damage.

psinuse 01-30-2012 01:51 PM

I'm a big stickler for doing things right the first time rather than doing them more than once. That's me though. There are a few more issues to consider when building one of these motors. Best bet is to get a factory manual to go off of for the rebuild. I'd personally put in a new crank in it to be safe, your going to have to pull the block halves apart anyway so you might as well just do it all new...

flewthecoupe 01-30-2012 01:52 PM

Thanks brfatal, good to know. I've rebuilt a couple engines with spun bearings, most recent was a Ford 3.8, and had no issues beyond the crank needing ground.

psinuse, what's the reasoning behind a new crank as opposed to turning the old one? Are they weak and can't handle abuse once turned? I ask because my experience is with American iron and I've never seen or heard of an issue with turning a crank and putting it back in after a spun bearing. Thanks for any added info.

psinuse 01-30-2012 01:54 PM

These motors are not like the normal inline and V style motors....Lots of odd little things that make them different, but also make them more prone to other issues that you wouldn't likely see on one of the normal style motors.

brfatal 01-30-2012 03:08 PM

[quote=psinuse;275065]I'm a big stickler for doing things right the first time rather than doing them more than once. That's me though. There are a few more issues to consider when building one of these motors. Best bet is to get a factory manual to go off of for the rebuild. I'd personally put in a new crank in it to be safe, your going to have to pull the block halves apart anyway so you might as well just do it all new...[/quote]

Yep. New oil pump too. Factory head-bolts should probably be replaced as well.

flewthecoupe 01-30-2012 03:09 PM

Thanks everyone... talked to a machine shop... and to some others... no one recommends keeping the crank once a bearing is spun.. nor the rods for a whole that spun a bearing... so now looking at a short block regardless.

so.. the machine shop also recommended redoing the heads, adjustments, pucks (never heard of pucks). thoughts on that?

turmic 01-30-2012 04:13 PM

Yeah, I'd replace the oil pump and all of the oil system parts. Unless you feel like going over it with a fine tooth comb to make sure a shaving doesn't get back into the new block.

psinuse 01-31-2012 08:24 AM

[quote=flewthecoupe;275072]Thanks everyone... talked to a machine shop... and to some others... no one recommends keeping the crank once a bearing is spun.. nor the rods for a whole that spun a bearing... so now looking at a short block regardless.

so.. the machine shop also recommended redoing the heads, adjustments, pucks (never heard of pucks). thoughts on that?[/quote]

Pucks is actually not the right name. They are called shims and they go over the buckets that cover the valve springs. The first illustration shows what I am talking about:
[IMG]http://www.howmotorcycleswork.com/images/scans_resized/img053.jpg[/IMG]

I know it says motorcycle, but it's pretty much the same. I'd give the heads a once over and have them cleaned and checked for straightness, regrind valves if needed. replace any broken pieces. Might as well since you have it apart. I might also recommend checking out the cost of rebuilding it yourself verses having it done. A new Subaru shortblock is close to $2000 now with the cost increase, but you get a warranty as well.


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