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S Chassis Technical discussion related to the S Chassis such as the S12, S13, S14, and S15.


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Old 05-11-2020, 10:29 PM   #1
astro.domine
 
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First post: What happened to my SR20DET cylinder walls??

I'm in need of the input of an experienced engine builder.

I just tore down my SR because the rings didn't seat well after rebuild (was running too rich), and I'm concerned about the cylinder wear. Had ~13,000mi on rebuild.

As you can see, the exhaust side has vertical streaks on all cylinders - is that normal? But what's worse is cylinder #1, which has circular grooves deep enough to feel with a fingernail. What would cause this??

Do you think a hone and new rings will suffice?

Cylinder #1
https://imgur.com/IawmjVl
#2
https://imgur.com/bbZ5SHK
#3
https://imgur.com/VATwdfs
#4
https://imgur.com/Yds4WJw

Specs:
-Wiseco 86.5mm pistons (bored to match)
-Eagle Rods
-ACL Bearings
-ARP Head and Main Studs (crank was line-bored)
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Old 05-12-2020, 08:00 AM   #2
tuzzio
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I'm no professional engine builder, but i don't think thats going to hone out.
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Old 05-12-2020, 08:32 AM   #3
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someone did a poor job of measuring piston to wall clearances...take both pistons and block to machine shop to have them measure it and see if they can hone it to match or if you need to go a size up in pistons...
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Old 05-12-2020, 10:27 AM   #4
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Quote:
Originally Posted by jedi03 View Post
someone did a poor job of measuring piston to wall clearances...take both pistons and block to machine shop to have them measure it and see if they can hone it to match or if you need to go a size up in pistons...
This is what I'm dreading. I don't see how they could hone to match if the clearance was already too big? (evidenced by the vertical marks)

Man, I really don't want to buy new pistons again!
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Old 05-14-2020, 08:51 AM   #5
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if they did it to loose then they dont know the expansion rate of the material...or were trying to play it "safe"...i would get another short or bare block and start over...
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