First post: What happened to my SR20DET cylinder walls?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

astro.domine · 05-11-2020, 10:29 PM

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)

tuzzio · 05-12-2020, 08:00 AM

I'm no professional engine builder, but i don't think thats going to hone out.

jedi03 · 05-12-2020, 08:32 AM

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...

astro.domine · 05-12-2020, 10:27 AM

Quote:

Originally Posted by jedi03

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!

jedi03 · 05-14-2020, 08:51 AM

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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05-11-2020, 10:29 PM	#1
astro.domine Join Date: Jan 2019 Location: Seattle Age: 28 Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	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)

05-12-2020, 08:00 AM	#2
tuzzio Nissanaholic! Join Date: Oct 2013 Location: Western Mass. Posts: 2,254 Trader Rating: (3) Feedback Score: 3 reviews	I'm no professional engine builder, but i don't think thats going to hone out.

05-12-2020, 08:32 AM	#3
jedi03 Nissanaholic! Join Date: Jul 2008 Location: albuquerque Posts: 1,784 Trader Rating: (8) Feedback Score: 8 reviews	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...

05-14-2020, 08:51 AM	#5
jedi03 Nissanaholic! Join Date: Jul 2008 Location: albuquerque Posts: 1,784 Trader Rating: (8) Feedback Score: 8 reviews	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...