How bad is this crack?
Thread Starter
Teching In
Joined: Sep 2009
Posts: 12
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How bad is this crack? I bought a low mileage LS2 and was working on swapping the heads and cam. Ran across a crack in the block. I can't get the picture to upload but the crack is between the water jacket and the piston sleeve, goes down about 3/4 of an inch from the top of the block. How bad is this? Can it be fixed? Does it need to be fixed? I plan on using this motor for drag racing making about 550 hp at the flywheel.
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TECH Apprentice
Joined: Oct 2007
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I don't think there are that many machine shops that are familiar with these blocks. I don't see why the sleeve can't be removed, the block welded and machined, then a new sleeve put in place. The sleeve does all the work containing compression, etc., not the block. This isn't like an old SBC400, they' were notorious for cracking between deck holes and bores. There's nothing that can be done for those, but I'd sure think this one could be repaired. Where are you located? I have a shop that I'd like to have take a look at it, they do a lot of LS engine work.
If not Ill buy it from you to send to them. PM me if interested.
I don't think there are that many machine shops that are familiar with these blocks. I don't see why the sleeve can't be removed, the block welded and machined, then a new sleeve put in place. The sleeve does all the work containing compression, etc., not the block. This isn't like an old SBC400, they' were notorious for cracking between deck holes and bores. There's nothing that can be done for those, but I'd sure think this one could be repaired. Where are you located? I have a shop that I'd like to have take a look at it, they do a lot of LS engine work.
crack I'm looking at your photo and I am not sure that is a crack I'm seeing. It may be a surface imperfection.
I repair a lot of cracked LS7 blocks and I get a few cracked LS2 blocks in from time to time to repair. If the aluminum is cracked, the iron liner will always be cracked. Is the liner cracked or not? If not, get the block decked. It will most likely clean up.
With the LS7 blocks I machine out the liner, weld the block, stress relive it, then machine the hole for a new Darton Seal Tight liner. Most folks want the entire block done but one hole can be done if there are budget constraints. The LS2 is different however. There is no real fool proof way to install just one replacement liner in these blocks. The entire block must be sleeved after the bad hole is welded. This can be justified if one is looking to use the block for a big inch build up, otherwise a replacement block would be a more cost effective for a daily driver.
Steve
I repair a lot of cracked LS7 blocks and I get a few cracked LS2 blocks in from time to time to repair. If the aluminum is cracked, the iron liner will always be cracked. Is the liner cracked or not? If not, get the block decked. It will most likely clean up.
With the LS7 blocks I machine out the liner, weld the block, stress relive it, then machine the hole for a new Darton Seal Tight liner. Most folks want the entire block done but one hole can be done if there are budget constraints. The LS2 is different however. There is no real fool proof way to install just one replacement liner in these blocks. The entire block must be sleeved after the bad hole is welded. This can be justified if one is looking to use the block for a big inch build up, otherwise a replacement block would be a more cost effective for a daily driver.
Steve
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Thread Starter
Teching In
Joined: Sep 2009
Posts: 12
Likes: 0
I am pretty sure it is a crack in the block. It doesn't show up well in the picture but with the right light you can see the line going down the outer wall.
I don't see any crack on the sleeve though?
There is a wear mark that looks a little different then the other cylindars. In the top half inch of the sleeve most cylindars have a band of wear that looks different from the main bore, like less wear. On this one the band is there but there is a section that shows the same wear as the main bore. Not lined up with the crack but within a half inch.
Are there any good tests for a crack? I shot some WD40 in the crack and it looks like it might be coming out as far down as 1/4 inch but is hard to tell.
I don't see any crack on the sleeve though?
There is a wear mark that looks a little different then the other cylindars. In the top half inch of the sleeve most cylindars have a band of wear that looks different from the main bore, like less wear. On this one the band is there but there is a section that shows the same wear as the main bore. Not lined up with the crack but within a half inch.
Are there any good tests for a crack? I shot some WD40 in the crack and it looks like it might be coming out as far down as 1/4 inch but is hard to tell.
crack check First, have someone run a dial bore gauge in that hole to see how round it is. See If the iron liner is out of round in comparison to the other cylinders. If it is way out of round then you can be pretty sure the aluminum is cracked.
Zyglo is used to check for cracks, especially in aluminum. Most welding supply places have a small spot check kit or you can purchase the cans individually. I think they run around $85 for the cleaner, penetrant and developer. You don't need the $$$ black light kit for that.
Steve
Zyglo is used to check for cracks, especially in aluminum. Most welding supply places have a small spot check kit or you can purchase the cans individually. I think they run around $85 for the cleaner, penetrant and developer. You don't need the $$$ black light kit for that.
Steve
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
