3 blocks all cracked in the same spot...

Rcks4me

New Member
Nov 3, 2011
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fresno ca, usa
So I'm attempting to build a 7mgte and so far all 3 blocks I've had at the machine shop have cracks going from the water jacket to the head bolt hole. 2 blocks were the older "light" blocks and the last was a newer "heavy" block, the heavy only having 1 tiny crack and the other two having 3 big cracks.
From my research it is almost impossible to find an older block without the cracks. What happens if I build a monster 500/700hp with one with a crack in the deck? It sounds like a bad idea to me but if it's nearly impossible to find one without cracks I may not have another option. Is it repairable? Is it not that big of a deal? Should I scour the earth looking for a crack free block?

Thanks for any advice...
 

suprarx7nut

YotaMD.com author
Nov 10, 2006
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I've seen that, but i've done 3 builds myself and never noticed it on my own blocks. And one had 320k miles...

I'd say keep looking. You can definitely find a good block and you will surely be punished for using a poor block with cracks if you settle.
 

Rcks4me

New Member
Nov 3, 2011
24
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fresno ca, usa
topekamk3;1779042 said:
It's only a good idea if you like to do rebuilds or pick parts up off the ground

Lol, I'd love to hear an elaboration on your experience with blocks cracked in this way..
How did they fail? How much hp was it producing when it failed? Were you running studs or bolts? Do you actually have any experience with blocks cracked like this?
 

GrimJack

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Dec 31, 1969
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idriders.com
suprarx7nut;1778889 said:
I've seen that, but i've done 3 builds myself and never noticed it on my own blocks. And one had 320k miles...

I'd say keep looking. You can definitely find a good block and you will surely be punished for using a poor block with cracks if you settle.
Agreed. I've seen it, however, I've seen lots more good blocks than cracked ones. If I had to guess, I'd say you've have poor luck so far, but finding a clean block shouldn't be difficult.