Keep cracking heads!
12-19-2017, 12:32 PM
#21
TECH Resident
Where are you pricing factory bolts that cost 350.00? Have you had your torque wrench calibrated lately? Could be you are over torquing the bolts. You might want to go with studs to prevent the block threads from deforming after so many tightening sequences. Just some thoughts....
12-19-2017, 01:17 PM
#22
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I priced the bolds out from 3 different Chevy dealerships. I used a Mac torque wrench that has been calibrated recently. I am debating on weather I could use the ARP bolts again or if I should just get cheap stretch bolts. I don’t know what’s happening. I talked things over with the head rebuilder and I really don’t think it’s his fault. He said he pressure tests the heads at 100 psi and heats them up too. But this time I ordered a new head from gm and I’m going to have valves and springs put in it. And I have been following the arp instructions and torquing them at 75 ft pounds. In 3 steps
Last edited by Silverado87k; 12-19-2017 at 01:24 PM.
12-20-2017, 05:17 PM
#24
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Yes 3. 1st original head (I think) 2nd was a remanufactured gm Head from a local rebuilder. 3rd was also remanufactured gm Head that he exchanged under warranty. This shop only rebuilds heads. Thats what they specialize in. Both heads that I put on cracked within 500 miles of driving. I don’t know why they are cracking. That’s why I posed this thread. I have checked everything. Surfaces are flat. The truck is not getting hot. No blockages. They just crack. I’m very meticulous with everything I do so I know it’s not me and my work. I know that these heads are netorious for cracking in the exact spots that mine have been. But 3 in a row??? Maybe I should buy a lottery ticket.
12-20-2017, 07:33 PM
#26
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Yes 3. 1st original head (I think) 2nd was a remanufactured gm Head from a local rebuilder. 3rd was also remanufactured gm Head that he exchanged under warranty. This shop only rebuilds heads. Thats what they specialize in. Both heads that I put on cracked within 500 miles of driving. I don’t know why they are cracking. That’s why I posed this thread. I have checked everything. Surfaces are flat. The truck is not getting hot. No blockages. They just crack. I’m very meticulous with everything I do so I know it’s not me and my work. I know that these heads are netorious for cracking in the exact spots that mine have been. But 3 in a row??? Maybe I should buy a lottery ticket.
If your busting Non-Castech heads.....YOU are doing something wrong!! Your torque wrench would be my first suspect, I know you stated that it was calibrated......That doesn't mean anything if the calibration was performed incorrectly!
Buy some GM Performance Parts head bolts.....Use a different torque wrench to obtain the initial torque then stretch them in place using a degree wheel adapter. Or borrow a known good Snap-On TechWrench.
On the other hand.....I wouldn't waste ANY money fixing a 5.3L, You probably could have bought a good used LQ4 6.0L for the money you've blown chasing your tail.
12-20-2017, 09:32 PM
#27
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Only the "862" & "706" Castech casting are known to crack.....Even then, It is blown way out of proportion on the internet as less than 1% of the problem heads ever crack.
If your busting Non-Castech heads.....YOU are doing something wrong!! Your torque wrench would be my first suspect, I know you stated that it was calibrated......That doesn't mean anything if the calibration was performed incorrectly!
Buy some GM Performance Parts head bolts.....Use a different torque wrench to obtain the initial torque then stretch them in place using a degree wheel adapter. Or borrow a known good Snap-On TechWrench.
On the other hand.....I wouldn't waste ANY money fixing a 5.3L, You probably could have bought a good used LQ4 6.0L for the money you've blown chasing your tail.
If your busting Non-Castech heads.....YOU are doing something wrong!! Your torque wrench would be my first suspect, I know you stated that it was calibrated......That doesn't mean anything if the calibration was performed incorrectly!
Buy some GM Performance Parts head bolts.....Use a different torque wrench to obtain the initial torque then stretch them in place using a degree wheel adapter. Or borrow a known good Snap-On TechWrench.
On the other hand.....I wouldn't waste ANY money fixing a 5.3L, You probably could have bought a good used LQ4 6.0L for the money you've blown chasing your tail.
It is a really nice Mac torque wrench and I know it’s dead nuts. Also. The head rebuilder told me he has seen just as many non castech heads come in as cores cracked as castech heads. Also he said he has seen the same amount of 706/862 come in cracked. He cant tell a difference in the amount of either or that fail. I don’t know what I could be doing wrong. I have built quite a few engines and know what I’m doing. But the whole stretch bolt thing vs arp is making me wonder. If this head cracks a new engine will go in or I’ll just get rid of the truck and be done with it
12-20-2017, 10:48 PM
#32
TECH Senior Member
Is it always the same place on the head? Sorry if this has been answered...
12-20-2017, 11:23 PM
#35
TECH Senior Member
ALWAYS the same side... to me that says STILL something about that block. Is it at all possible that a hot spot has developed in that area, maybe an obstructed block-head coolant passage? Just shooting in the dark here... I look at constants in a problem; here it's always the same side of the block. Whatever the problem is it will be related to that somehow.
12-21-2017, 09:31 AM
#38
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I have checked the block and it is flat. I used a 24” starret straight edge that I borrowed from a machine shop. That is as straight as a straight edge gets! I’m using factory gm Head gaskets. As for a hot spot in the block? I don’t know. I guess it’s possible but I have flushed the system a few times now.
