Quickin

It comes already bored 4.125, but does that mean its sleeved already at the factory?

I mean, an LS2 can be 4.125 bore, but a shop needs to resleeve it to do it. What's in the cylinders when an LS7 block comes from the factory...a factory sleeve?
Also, how can a sleeve be pulled out and a new one put in and than be machined to have a bigger bore on an LS2. Where's the extra thickness in the new sleeve? Or is the actual aluminum part of the block machined bigger first

I know, newbie question for that many posts


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69firebird

iTrader: (14)

the LS7 block is essentially a resleeved LS2 block.

it comes in a 4.125 like you mentioned, theres really no reason to have it resleeved once you get it.
ed

stang90gt50

iTrader: (6)

It is cheaper and stronger to send Race Eng. a LS1 or LS2 block and have them resleeve it. There is almost no reason to use a factory ls7 block for a buildup.

Steve - Race Eng

iTrader: (1)

The cast in sleeve of an LS2 block is first machined out. These sleeves are cast in so one can not drive them out. Then the aluminum is machined out to allow installation of a larger outside diameter replacement sleeve. The larger outside diameter is necessary to accomdate a larger inside bore diameter, usually 4.125" but we can go larger.

The LS7 blocks have pressed in dry liners so it is possible to drive them out. I have driven sleeves out of a couple of LS7 blocks but now bore them out. The sleeves break at the bottom when driving them out making a mess out of my aluminum driving tool.

The stock LS7 sleeve is sufficient for most uses. I resleeve these blocks for folks looking to build a supercharged or nitrous engine or for those looking for a larger bore. The LS7 Darton sleeve will go .060" over 4.125" bore or 4.190" max.

Steve

Quickin

Thats what I thought, thanks.

So when my LS6 block was made into a 4.125 bore, the factory sleeve was machined out, then the outer diameter of each aluminum cylinder was also made larger to except the larger new "thicker-walled" sleeve?

So is it fair to say that a re-sleeved LS1, LS6 or LS2 is just as good or better than a factory LS7....if a 4.125 bore is the goal?


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stang90gt50

iTrader: (6)

That is correct.. a darton sleeved 4.125" is stronger than the factory ls7 block and can be bored out .060 for rebuilding etc..

$600 for a bare block + $1600 in Race Eng work gets you a stronger block for $2200 than a new $3k ls7 block.


Ls7 block isnt such a good deal when you look at it that way. when it comes down to $1500 ill consider it.

Quickin

Steve,

Also, why not have a sleeve sit on a shelf (if you will) at the bottom of the cylinder so it can't drop. Maybe I totally don't understand the inside of a cylinder, but why not machine it out and leave some in the bottom for the sleeve to sit on? It wouldn't interfere with the piston or rod would it?

Steve - Race Eng

iTrader: (1)

The MID wet liner sits at the bottom of the coolant jacket on a robust seating flange. If properly installed these sleeves can't sink.

On a dry liner, I like to see .100" of seating width. This can only be accomplished by seating on the sleeve flange - Darton flange diameter is increased to get sufficient seating width. I seat the sleeves with a deck plate after installation to make certain they are fully seated. You would have to get the block extremely hot for these to sink. So hot that the engine would be toast anyway.

You would break through into the adjacent cylinder if you tried to bore the block large enough to get .100" seating width at the bottom of the cylinder and still have a large inner bore.

Ford uses the bottom of the aluminum bore to seat their press in factory sleeves in the 4.6 blocks. These sleeves are roughly .060" wall as I recall. They get away with it for production use but I don't like it.

Steve