Cracked block by head bolt, advice please!
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Teching In
Joined: Jul 2005
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From: Ohio
Cracked block by head bolt, advice please! I know a picture would be much better, but I am wondering if this has happened to anyone else. I was having my motor rebuilt by a local machine shop with Je pistons and crower rods, and after they bored and honed the block, they told me they found a crack. I guess the previous owner of the car screwed the head stud too deep into the first hole, causing the block to crack a little in the deep inside of the bolt opening, and on the outside right next to were the water pump gasket would be. The crack is prety thin, about a little less than an inch long. They said it was at a spot that they normaly wouldn't look at for cracks. They told me it should be ok, but can't guarantee it. They should of saw it before they bored and honed that block, or ordered me the pistons/rods as I would just went with an iron block, but too late for that now. A
nyways, has this happened to anyone else and they got away with using the block? I bought the car already modded. It was a heads/cam motor, and I guess that crack was there the entire time. I took the car to a local shop in Ohio last year for trans work, and they said it had a small coolant leak, but couldn't find it. It wasn't anything major though. And the car always ran a bit hot, at around 192 degrees. Thats with the fan switch on high and a 160 t-stat. Not sure if it was leaking coolant from somewhere else, or from that one certain spot. Any advice? Anyone got a good deal on a bareblock that they guarantee doesn't have any cracks? Thanks for any advice..
nyways, has this happened to anyone else and they got away with using the block? I bought the car already modded. It was a heads/cam motor, and I guess that crack was there the entire time. I took the car to a local shop in Ohio last year for trans work, and they said it had a small coolant leak, but couldn't find it. It wasn't anything major though. And the car always ran a bit hot, at around 192 degrees. Thats with the fan switch on high and a 160 t-stat. Not sure if it was leaking coolant from somewhere else, or from that one certain spot. Any advice? Anyone got a good deal on a bareblock that they guarantee doesn't have any cracks? Thanks for any advice..
Last edited by TransAmMarathon; Jan 14, 2012 at 04:52 AM.
I wouldn't risk useing that block. For the price of a new block you'll save in the long run if the crack gets bigger and hydrolocks the engine. Too much time and money involved not to get a new one. Check with some sponcers many require core's with new short blocks they should be able to get you a bare block, and you can use the rotating assembly you already bought. good luck.
That sucks. I would have a hard time trusting it too. It's a shame they didn't find it before the work was done. There are 2 brand new LS1 blocks for sale in the For Sale section:
https://ls1tech.com/forums/lsx-parts-sale/345009-f-s-brand-new-ls1-blocks.html
https://ls1tech.com/forums/lsx-parts-sale/345009-f-s-brand-new-ls1-blocks.html
Teching In
Joined: Jul 2005
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From: Central Massachusetts
No way I'd use that block. The previous owner might have put the studs in without using compressed air to blow out the holes first. Just a couple drops of fluid in the bottom that the stud tries to compress would be enough to cause a crack.
Actually, depending on how badly cracked and where, its not a big deal for most power levels. We've run a cracked, unrepaired block for over 30k miles with a heads/cam/nitrous setup. I'm going to reuse the block again, but I'm finally going to tig weld up the cracks so they don't grow, and then chase the head bolt threads.
Teching In
Joined: Jul 2005
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From: Central Massachusetts
Originally Posted by Brains
Actually, depending on how badly cracked and where, its not a big deal for most power levels. We've run a cracked, unrepaired block for over 30k miles with a heads/cam/nitrous setup. I'm going to reuse the block again, but I'm finally going to tig weld up the cracks so they don't grow, and then chase the head bolt threads.
I pass on cracks at the head stud level... 
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I have a block that was cracked on the boss for the lower left head bolt on the rear. You could see the protrusion of some of the block material at the base of the boss. I had my machine shop look at it and they found that someone had previously attempted to helicoil that bolt hole and had botched it up pretty badly. The shop drilled out the hole, ground out the damaged block material at the base of the boss, welded up the damaged area, redrilled the bolt hole, and installed a TimeSert. The block is now better than new and the cost was less than $300. It sounds like you already have quite a bit invested in that block; before you scrap the block, find a good shop in your area that knows how to handle aluminum block repairs and see what they can do for you.
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TECH Addict
Joined: Nov 2001
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From: LaConner WA
Since they discovered the crack AFTER boring and honing it, AND they probably bolted a deck plate on it for the honing process, THEY could very well have cracked it themselves. I would have the block pressure checked. If it leaks coolant then THEY did it since you would've noticed a coolant leak on your engine before pulling it if it were already cracked. Just a good way to find out the truth IMO.
9 Second Club
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Originally Posted by CharlieLed
I have a block that was cracked on the boss for the lower left head bolt on the rear. You could see the protrusion of some of the block material at the base of the boss.
I have seen this probably 20 times. People put the head bolts or studs in without cleaning the holes out. In that 20 times it hasn't hurt one thing. One of the blocks that I used in a motor build up had a chunk missing at bottom rear right next to the rear cover behind where the flexplate would be. That motor ended up being forged heads,cam,bottle,with an auto.......that went damn fast.
What I am telling you is that it will be fine.
Its easy to say get a new one. But if it were my money and time invested in the block I would probably try to salvage it. It does suck thats for sure. If the block is bare I would take it and have it TIG welded at the very least. Have you ever seen top fuel blocks that have been repaired several times? I mean big *** windows welded in!! Weld it, grind it, forget about it.
Originally Posted by GueSS Who
I have seen this probably 20 times. People put the head bolts or studs in without cleaning the holes out. In that 20 times it hasn't hurt one thing. One of the blocks that I used in a motor build up had a chunk missing at bottom rear right next to the rear cover behind where the flexplate would be. That motor ended up being forged heads,cam,bottle,with an auto.......that went damn fast.
What I am telling you is that it will be fine.
What I am telling you is that it will be fine.
I heard about getting water in the bolt holes so many times, it scared the CRAP out of me when we were doing my heads/cam swap so I was very careful to make sure all of that fluid was removed!
Id be careful trusting it too, but like a few guys said it could be perfectly fine and you might not even notice an issue with it.
Id be careful trusting it too, but like a few guys said it could be perfectly fine and you might not even notice an issue with it.
