School me on rebuilds

clrussell

clrussell

pro-procrastinator
Sep 23, 2013
5,928
396
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So I'm sure this is been posted before and people probably get tired of helping out the "newb", but I'd appreciate any and all help I can get.


Donor motor for my lly tahoe project.

Motor is an lb7 engine with unknown miles and I bought it as a "core" knowing it was smoking when pulled. However Injectors were changed at the same time and truck wasn't smoking when it left the shop. So 50/50 shot it was injectors or low compression.

Checked compression today using one injector in the hole
I was checking and no rocker bridges or glow plugs in/ on the engine. On my engine stand using a starter to crank it over. I had sprayed a little fogging Oil in the cyls prior to cranking and hand cranked it a few times then starter cranked it.

Driver side was all under 200 psi so I didn't even check the passenger side.

Here's #8 cyl. Not sure why it's so dull looking and that's my first question. What caused it to be so dull in the cyl walls? The entire driver side looks like this. Talking to the shop who I got the engine from just now they said it got drove with bad gaskets for a while then gaskets got put on it and it still smoked.
 

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tsd_billy

Member
Apr 5, 2016
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0
16
oklahoma city
Im dealing with the same issue. Only worse. My engine had a bad knock and smoked like it burned oil. I pull the up pipes off and driverside and entire turbo was full of oil so i pull the head and all my pistons dont have holes and the cylinders dont even look washed. And this all happened within 20 k miles after a new set of injectors


Sent from my iPhone using Tapatalk
 
WVRigrat05

WVRigrat05

Wound for sound
Jan 1, 2011
3,081
4
38
36
French Creek, West Virginia
It's pitted pretty bad. It's hard to say without knowing its history. Could have been driven forever with bad gaskets, then tore down outside or been allowed to get wet and not cleaned up then only driven a short time after the work causing all the rust and pitting.
Could have been in a flood and sat.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,623
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113
Phoenix Az
looks like either cyl's got washed down or coolant sitting in the cyl ate at it. are the dull spots your seeing inline with the piston skirts?

stock protrusion is in the .010-.014 range IIRC. measure over the wrist pin.
 
TheBac

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,577
1,833
113
Mid Michigan
My protrustions were all between .012 and .015, but yours might be different. As long as they are all close to the same (like compression figures), then you go from there.

x2 on what James said. How far do you want to get into this engine? Could simply try to hone the cylinders and see first....
 
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