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Discussion Starter #1
I purchased a used shortblock over a year ago from a distinguished memeber here on SF which has HC pistons, rods, but most importantly billet mains. Finally I've come to the point in my build where I'm ready to assemble the engine and dump it in and upon removing the old head gasket material I found some unwelcome surprises. Between a few of the head stud holes and coolant passages are tiny cracks. Has anyone else seen something like this? Is it cause for concern? Can it be fixed or is the block trash? My thinking tells me that coolant could push through to the head stud area and up into the cylinder head but probably stopping at the washer under the head stud nut. Then of course there is the question will it enlarge when I torque the head down, will it enlarge when 1200hp is pushing up on it. This area of the block seems very weak and thin but also not heavily structural so I feel like this may be a common thing among high hp engines.









 

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Id personally send it to a machine shop to have it checked. they have the equipment to give you a proper assessment of the cracks.
 

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Drive Hard
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never seen cracks like these on all 2jzgte blocks i have rebuilt in the past
 

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yeah that doesn't look good at all !! I think you've got a paperweight there , also those cylinder walls don't look very good
 

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I had this happen to my original 2JZGTE block so I bought a GE block rather then try and fix it. However a mate bought it off me and had the one and only crack ground out and welded up before he used it. He didn't have any issues with it cracking any further.
 

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Boost Junkie
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I've never seen that before. Have it checked out.

Steve
 

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8 second 6 speed member
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I've had an old block crack between the head stud thread and the water ports. Slowly lost water and couldn't figure out where until I tore the engine down. But ran perfectly making 1000rwhp all day at the race track.
 

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Toyota Master Tech
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Many different types of heads and blocks can develop cracks in these areas for many reasons and some can be repaired using special techniques, however i would not set out to use one with that many cracks in key areas looking for big power. Get your money back
 

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Discussion Starter #13
Many different types of heads and blocks can develop cracks in these areas for many reasons and some can be repaired using special techniques, however i would not set out to use one with that many cracks in key areas looking for big power. Get your money back
I think asking for any kind of compensation this long after the transaction is completely out of the question. My fault for not cleaning it up and doing a thorough inspection right after I got it. I will make some calls to a few places that specialize in supras tomorrow to see if they have seen this and what their recommendation would be. There is no chance I'm running it the way it is, its either getting fixed or I will have another shortblock prepped for billet mains and swap over the rods and pistons. Anyone know if used billet mains can be line bored to another motor or are they one and done?
 

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Mains should be fine to reuse any competent machine shop can do that. Reguardless if shops have seen this before and make you feel comfortable or not i would not use that block. Those cracks are just what you see more can be lurking in other spots below the surface. Nice work spotting them though most would have overlooked them. I am a toyota master and have seen them before but that does not matter nor do what "specialized" supra shops have to say. Your answer is right in front of you good luck

To answer your question it can be fixed. Notice though that your cracks are on the exhaust side
 

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2j blocks are a dime a dozen and almost free(ge blocks) just pull one and swap the good stuff over.
 

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Mains should be fine to reuse any competent machine shop can do that.
You cant use mains in a different block that they are honed to. 99% of the times they are off, and even if they are off by only tenths of a mm, you will need to lower the mains by several millimeters to get them centered again, I wouldnt bother.
 

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I've had this happen between the water jacket and head stud on the intake side of #6. Just decided to buy another GE block and start over. Had billet mains and all. So it's now repaired, and I need to find a cool beater to toss it in.
 

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You cant use mains in a different block that they are honed to. 99% of the times they are off, and even if they are off by only tenths of a mm, you will need to lower the mains by several millimeters to get them centered again, I wouldnt bother.
A lot of big machine shops wont bother with already honed billet mains to fit a block they wernt honed/fitted to.

OP It appears your power is getting up there I personally would not bother with that block, Might be worth getting inspected but to be honest with you I personally would not bother as you cant tell how far down the cracks go, you wont see them with the naked eye. and if they are already that visible chances are they are spreading and your just asking for trouble. might last with lower cyl pressures but unlikeley at your level..

-Saif
 

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What would even happen with those cracks ? I can't imagine the block would fail catastrophically from water jacket cracks. Maybe take it to the machine shop and get the block decked and see if it cuts below the cracks. Then run it till it blows assuming you can't reuse the mains in a new block.
 
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