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2000 Impreza 2.5RS
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73 Posts
Discussion Starter #1 (Edited)
I cleaned the block surface with a razor blade, Scotchbrite pads, and WD-40.

I also used some degreaser with a hose to clean out the coolant passageways which were covered in white crud, probably from the Blue Devil sealer.

Here's a before



and after:



before album: Before - Album on Imgur

after album: after - Album on Imgur

There was some green dust from the Scotchbrite pads, but I hosed it down again with some degreaser, then used a bunch of WD40 in the cylinders, bolt threads and oil passages.

final - Album on Imgur

I used a machinist's straight edge and some feeler gauges, and it looks like the block is MOSTLY flat within .002".

The heads have been sent out to be rebuilt by a shop. I think they're doing a valve regrind, resurfacing, and something else. They quoted me $330.

I bought the Six Star MLS headgaskets. I'm hoping I've prepped everything OK. What do y'all think?
 

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2001 Impreza 2.5RS+T 2001 Legacy GT
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1,236 Posts

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I ❤ BOOBIES
99 Coupe
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17,029 Posts
It needs to be much cleaner than that, if you put that motor together you'll have issues.

Use a non-marring flat tool like a planed piece of wood or a durablock (i use a 16" durablock like this) and 800 grit wet sanding paper, then just work the block and head surfaces evenly until theres no gasket material left, dont push hard just let the paper do the work but keep it wet with water or a little soap/water, and rise the surface and paper often. Once its clean you should *almost* see your reflection in the surface, but that finish with 800 grit is fine.

Once your cleaned up, you can check the head/block for flatness (you'll need a machined square for this, this is what i use to check surface flatness)
 

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Registered
2000 Impreza 2.5RS
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73 Posts
Discussion Starter #7
It needs to be much cleaner than that, if you put that motor together you'll have issues.

Use a non-marring flat tool like a planed piece of wood or a durablock (i use a 16" durablock like this) and 800 grit wet sanding paper, then just work the block and head surfaces evenly until theres no gasket material left, dont push hard just let the paper do the work but keep it wet with water or a little soap/water, and rise the surface and paper often. Once its clean you should *almost* see your reflection in the surface, but that finish with 800 grit is fine.

Once your cleaned up, you can check the head/block for flatness (you'll need a machined square for this, this is what i use to check surface flatness)
I put my motor back together and continued to have issues. I guess you called it Bansheeboy11

I created this thread about a year ago. I might try to pull the motor again this summer and do it right.
 

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I ❤ BOOBIES
99 Coupe
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17,029 Posts
800 and wet sand it, keep the surface and the paper clean as much as possible. The old gasket material and aluminum will easily clog the paper and give you scratches in the finish if its not clean.
 

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2001 Impreza 2.5RS+T 2001 Legacy GT
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1,236 Posts
a whizzy wheel!
 
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