Snkebait95

iTrader: (16)

I have what may be a dumb question, but I cant find an answer in any searches.

If all ls motors are externally identical, and all bore spacing is 4.4", then how does cylinder wall thickness vary in the different engines? An example would be you cant bore an iron 5.3l past 3.905" safely, but a 6.0l is a 4" bore already. If the two engines are externally identical and bore spacing is the same, why can one have a larger bore than the other? Im missing something. Thanks for any enlightenment!

cam

iTrader: (9)

They are not all built from the same block they are cast unique per displacement and the cylinders are sized accordingly. Some of the aluminum blocks have thicker sleeves than others though, and iirc the LS7 has the thinnest sleeves of them all. Numbers or which is what/who/where I cant say, im only going on memory here and its getting mushier with each passing year. Blah

Che70velle

iTrader: (6)

Yeah, I get what your saying snakebait. It's definately interesting, and tough, to keep up with all the different blocks and materials. For instance, the LS1 can be honed out an additional .005" to .007", while the LS2 can be safely bored and honed out an additional .035, which I was just taught with much embarrassment. There is much research to be done, that's for sure.

Snkebait95

iTrader: (16)

Well im pretty sure the aluminum blocks' thickness of the liner determines how much they can be bored. I dont understand why theres a difference in the iron blocks. I guess I should have left ls1s out of this question.

Why cant a 5.3l be bored to 4.030" like a 6.0l?
Where does the 6.0l Block get it's extra thickness from?
Where is cylinder wall thickness measured from on the block?

redtan

iTrader: (5)

You have to imagine a cylinder as two part...a cylinder within a cylinder. When the block is machined, first they create a hole for the liner to go in. The bigger the hole, the bigger the liner that can be put in. Different LS blocks have different sized "holes" while retaining the same bore spacing. This allows for bigger or smaller cylinder liners to be put in.

For example, a 6.0 has less material in between the two cylinders which allows for thicker cylinder liners that can be opened up to around 4.010.

A 5.3 (while retaining the same bore spacing) has more material between the two cylinders, which means there is less space for the cylinder liner. Since it's thinner, it cannot be opened up to more than 3.905.

A 6.2 block has the same bore spacing, but again there is less material between each cylinder meaning there is more room for a bigger cylinder and bigger cylinder liner that can go to 4.070

And this is exactly what companies like ERL work on when they sleeve a block. They take out the existing liner leaving a raw cylinder. Then they bore that guy out to allow for a bigger cylinder liner to be installed which can then be worked to 4.185 bores.

Tainted

iTrader: (9)

2 threads about this very subject already, have a look at 5.3 boring in gen III internal and theres another one in gen IV internal a lil further down.

Core shift is more common in gen 3 blocks which makes them a lesser candidate for boring while gen 4 blocks were a bit better.

Snkebait95

iTrader: (16)

Core shift sheds a little more light but,

In iron blocks only, where does a 6.0l get its sufficient cylinder wall thickness from, opposed to a 5.3l?

cam

iTrader: (9)

Only way to know for certain is cut one of each in half and take a look and measure. Either that or get searching, im sure the info is out there somewhere