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I am building my first ls3 engine ever. I just got the block back from the machine shop. I told them to make it that a 5 year old could put it together. Practically do all the heavy labor or checking clearances etc. I got home and placed the engine on my work bench and saw this crack! I am not sure if the machinist caught this! How bad is it? Is it repairable or am I SOL? I'm a little upset since I paid them a little north of $1400. The crack is on the front side I believe. The side where the cam retainer plate is on.
Thanks for the reply! I'll have to find someone in the near DFW with a TIG welder. I'm glad it's not structural, but still sucks that there is a crack....
May want to drill a shallow hole at the known end of the crack before welding. This will help prevent the crack from continuing...Never mind, looks like it tracks all the way to the other bolt hole. Zoomed in this far, it's hard to see what that bolt hole at the side is/does.
Lots of good info here, one thing that’s extremely important that hasnt been mentioned yet is heating the rest of the block before welding it. I agree with drilling above the crack if its possible but if you try and weld that crack on a cold block you will likely make it worse.
id hit the block with a propane or map gas torch and spread the heat evenly. Good luck!
cut a chamfer following the crack so the weld can penetrate further.
This is also good advice. When we'd manufacture weldments we'd always put a slight 45° angle on the piece to be welded on when you didnt have a 90° angle between the two pieces. It produces a "V" so the bead can penetrate both pieces well.
Unfortunately that is the weakest part of an aluminum LS block. I’ve got one in the shop cracked in the same spot. My block was dropped by the UPS guy, and I ended up getting a replacement block from the seller. Use a magnifying glass and look carefully to see where this thing goes. I’d look the entire thing over, both sides to see if you’ve got other damage. That block was dropped somewhere along the way….that’s the only way they will crack, and it doesn’t take much.
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How bad is this crack? 
