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Old 07-06-2019, 06:31 PM   #1
Scooby Newbie
Member#: 479363
Join Date: Dec 2017
Location: Las Vegas, NV
2004 WRX Wagon

Default Teardown/evaluation of ej205 stroker

I recently completed a 2.1 stroker build on a ej205 that had a blown head gasket I used all new parts, including OEM crank, Sti rods and Manley stroker pistons. New OEM water pump, oil cooler, oil pan, etc were also used. The block was bored for the new pistons.

Shortly after completion, I had issues with overheating. On two occasions, the coolant got up to 238deg F, caused by combustion gases getting in the coolant. I pulled the engine, and sent the head off to be machined. With the head off, I noticed some scoring on the cylinder walls, and wear on the piston skirts. Two of the rods also had some damage at the wrist pin attachment.

The engine never ran low on oil (didn't burn any either), and I didn't notice any mixing between coolant and oil. This engine (embarrassingly) has less than a 1000 miles When the car wasn't overheating, it ran great.

Is the piston/cylinder wear excessive? Is that something that can be honed out? Any idea what would cause the damage to the rod?

The engine is currently in pieces, but I may take this opportunity to buy a pre-built 2.5 shortblock for a hybrid...

Two of the pistons

Damage to the rod. Two are like this, the other two look brand new.

Cylinder walls. All four looked similar to this.

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Old 07-20-2019, 02:56 AM   #2
Scooby Specialist
Member#: 29292
Join Date: Nov 2002
Chapter/Region: SCIC
Location: Orange County CA
2004 WRX wagon


wow that doesnt even look broken in... for my 2.1 I had to run about 2500 miles to break it in.. I know that there are lots of people that have their ideas on how to break in, but here is mine. I was told to warm the engine up, and when driving get into 3rd gear and rev it up to 3000 and let the rpms fall to 2000 for about 25 miles a day. it was pretty annoying and I am glad to be out of that portion but I dont burn oil at all and it seems to be holding up really well as I have over 5000 on it now
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Old 07-23-2019, 10:20 PM   #3
Scooby Specialist
Member#: 25768
Join Date: Oct 2002
Chapter/Region: RMIC
Location: CO springs
2003 2.34 Long-Rod
SL performance, Slowbaru


Did you get the heads properly decked? this should never happen if you did.
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