Another bore question
Thread Starter
Teching In
Joined: Jun 2012
Posts: 15
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From: Georgia
Another bore question I have scoured these and other forums for a answer to the boring capabilities on aluminum 5.3's.
I've got an LM4 2004 from an Envoy with 1 rough cylinder and was wondering if anyone can confirm that these have the thicker cylinder walls?
Casting of block is 12566910
Seems to be all kinds of conflicting information on every thread I found.. Just would like a heads up if I'm wasting my time as I have a Iron block I can use if need be and I'm nowhere near a quality machine shop to seek advice.
I've got an LM4 2004 from an Envoy with 1 rough cylinder and was wondering if anyone can confirm that these have the thicker cylinder walls?
Casting of block is 12566910
Seems to be all kinds of conflicting information on every thread I found.. Just would like a heads up if I'm wasting my time as I have a Iron block I can use if need be and I'm nowhere near a quality machine shop to seek advice.
TECH Senior Member
Joined: Jun 2016
Posts: 22,288
Likes: 3,615
From: Central Cal.
This might cost a little, but bore the affected cylinder as far as is usually safe. If the damage is gone, bore the rest of the cylinders, If still there, trash the block, OR put in a new liner.
A lot of the 5.3 aluminum blocks are seimese bore blocks. Not all of them, but a lot are. I think you have an LM4 block. You can use a flashlight, and look into your water jackets on the block deck. If your cylinders are molded into one big unit, meaning there is no gap between the liners inside the water jackets, then that block can be safely overbored quite a bit. There are guys over on YellowBullet that have (I do not advise) bored those blocks .125. Its pretty common to see them go .030, if its one of the thick liner blocks. I guess you need to figure out which block you have, and how far you need to go.
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Thread Starter
Teching In
Joined: Jun 2012
Posts: 15
Likes: 0
From: Georgia
Thread Starter
Teching In
Joined: Jun 2012
Posts: 15
Likes: 0
From: Georgia
A lot of the 5.3 aluminum blocks are seimese bore blocks. Not all of them, but a lot are. I think you have an LM4 block. You can use a flashlight, and look into your water jackets on the block deck. If your cylinders are molded into one big unit, meaning there is no gap between the liners inside the water jackets, then that block can be safely overbored quite a bit. There are guys over on YellowBullet that have (I do not advise) bored those blocks .125. Its pretty common to see them go .030, if its one of the thick liner blocks. I guess you need to figure out which block you have, and how far you need to go.