How do I fix this major problem I have now, block cracked at cylinder head bolt hole

Hello All,

Well as you have all known I have been jumping through hoops trying to get this block back together. Now I have another issue, after breaking a chasing tap in the last cylinder head hole, and after breaking head bolts, I finally got my ARP studs in and WOW another one. After torquing down the studs per ARP instructions to 125 ft lbs. I observed a crack on the outside of the block on the trouble hole. The hole that has given me problems up until now, except for the broken cylinder head bolt, that was in another hole. I hope brazing by a qualified welding shop can fix this mess. I already have the heads and intake bolted down. Much advise is appreciated. Guys and Professionals please give me your input.

The head will have to be removed for that to be properly welded, plus the block will warp.

Are you sure the blocks cracked from the picture it almost looks cosmetic but in perons could be worse. Brazing might work but chances are it wont.

its a crack im sure, after I got the broken tap out of the same hole, I had to drill the hole larger for a helical insert, Im thinking the wall on the hole is too thin to hold the foot pounds. Also when I run my finger over the crack it has a slight bulge outwards.

That sucks can you tell if its running into any coolant or oil pasages? If not you might get away with drilling stop holes at each end but really the best bet would be a new block, it would suck to put it all together and have it leak or worse.

Id pitch the block and start over. The cost to properly fix that would exceed a used block and I would never trust it again. Complete engines can be found dirt cheap, at least around these parts.

To see that must have been heart-breaking...

Its risky but I say run it... Whats the worst that can happen... A water leak. Run plain water in the cooling system and see if it leaks. If it does there are several great block sealers available like KW Block seal for one. Your torque on the ARP studs is wrong no matter what you have been told. 110 is all you needed. This has been discussed with this build before when you posted those numbers. You have a lot of work in this block and its sad to see this happening. First a broken tap. Then drilling and an incert installed. Now this crack. No matter what, you are getting a lesson on what can and will happen when you attempt a build. Sorry for your problems but they are important lessons no matter what happens. Hopefully this is not going to leak because there isn't any water on that side of the bolt threads.

icanfixall said:

Its risky but I say run it... Whats the worst that can happen... A water leak. Run plain water in the cooling system and see if it leaks. If it does there are several great block sealers available like KW Block seal for one. Your torque on the ARP studs is wrong no matter what you have been told. 110 is all you needed. This has been discussed with this build before when you posted those numbers. You have a lot of work in this block and its sad to see this happening. First a broken tap. Then drilling and an incert installed. Now this crack. No matter what, you are getting a lesson on what can and will happen when you attempt a build. Sorry for your problems but they are important lessons no matter what happens. Hopefully this is not going to leak because there isn't any water on that side of the bolt threads.

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I would at least drill the ends so the crack doesnt grow.

icanfixall said:

Its risky but I say run it... Whats the worst that can happen... A water leak. Run plain water in the cooling system and see if it leaks. If it does there are several great block sealers available like KW Block seal for one. Your torque on the ARP studs is wrong no matter what you have been told. 110 is all you needed. This has been discussed with this build before when you posted those numbers. You have a lot of work in this block and its sad to see this happening. First a broken tap. Then drilling and an incert installed. Now this crack. No matter what, you are getting a lesson on what can and will happen when you attempt a build. Sorry for your problems but they are important lessons no matter what happens. Hopefully this is not going to leak because there isn't any water on that side of the bolt threads.

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If you are not going to build another block, I would attempt some sort of fix.

running this and hoping for the best is poor advice.

Run it like ya stole it and start seeking a replacement block ASAP...or better yet...get a replacement block and start anew!

Eff that block it's got bad Ju Ju going on!

I completely understand what you are saying, the manuals state one thing, forum friends state another and lastly ARP states another, so i did what ARP said, 125 ft lbs. Either way I look at it, Im screwed if I cant get this fixed. I will check with a welding shop tomorrow hopefully they can braze it, and save me money and another headache on trying to find another block. Believe it or not 7.3 idi blocks are not easy to find, even here in Phx.

Thanks,

icanfixall said:

Its risky but I say run it... Whats the worst that can happen... A water leak. Run plain water in the cooling system and see if it leaks. If it does there are several great block sealers available like KW Block seal for one. Your torque on the ARP studs is wrong no matter what you have been told. 110 is all you needed. This has been discussed with this build before when you posted those numbers. You have a lot of work in this block and its sad to see this happening. First a broken tap. Then drilling and an incert installed. Now this crack. No matter what, you are getting a lesson on what can and will happen when you attempt a build. Sorry for your problems but they are important lessons no matter what happens. Hopefully this is not going to leak because there isn't any water on that side of the bolt threads.

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Black Dawg.... Really. I prefaced my statement with... "Its risky but run it". You may have missed that part. What are the chances of this not being a problem... Or it being a problem... This is the last drilled and tapped hole in the block and... There are no threads in that area. Threads start 1 inch below the deck level and go down another 1 1/2 inch. You say its poor advice to run it. Whats the cost of running it compared to junking it. A lot of work with no knowledge if it worked or not. I continue to say run it and at least try it. Then if it wont work junk it but at least try it. Like I posted earlier... there is no coolant circulating around the carcked side of the block in this case. Is the block subject to a weakness in this area.. Probably yes is the only safe answer but to say junk it wothout attempting to use it... Nope. I do respect your rights to disagree. I just don't feel this block is junked without testing it first. If money wre no object then yes... Don't take a chance. Parts availibility is another. One good thing about all this is any 7.3 block will accept all the internal and external parts without issues. You just need to find a block with the same bore.

I would run it... I agree there is no coolant in that area. Even if it leaks you can run it while you save up for another block. You have alot of time invested now. Get the truck back on the road and see what happens. Junking the block without knowing if it leaks would be poor advice. There are several types of metal repair epoxy products out there that could be used to slow down or stop the possible leak before install of the engine. This would buy you some time to make another block ready for rebuild if you needed one.

run it...if/when it blows take the block fishing and put a dt360 in it

oregon96psd said:

run it...if/when it blows take the block fishing and put a dt360 in it

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Take the block fishing... Now thats funny I don't care what you say... Almost had to clean the puter screem....