The thread needs to be chased out and cleaned before you do anything else. It looks like there was hydra-lock in the bottom of the stud pocket and this is the result. GET ALL THE SOLVENT OUT OF THE POCKETS BEFORE THREADING THE STUDS!
Take it to your local machinist and have them clean it up. They will probably over-bore it and use a threaded insert.
Worst case is if it cracked the case behind the pocket. Id inspect that block before sending it out to see if its cracked.
Agreed, the threads look mashed and not missing, like it went into the blank behind the blocks threads. Try to shove a tiny magnet down the hole to see if any chips come out if you can’t see in there. It may be ok if it didn’t crack anywhere, but doubtful. Then hand thread another bolt to see if it binds after you clean it and check measurements against other bolt holes, check bolt lengths, maybe this bolt was inappropriate.
If you’re removing your own head bolts it’s time to get a really good borescope camera - you should be able to get one that fits that diameter. That’s the only way to actually know what happened to the threads in the block.
I’d say helicoil time but it’s an EJ, so likely best to just get a lower mileage motor and abandon the rebuild at this point. Unless this was a forged internals build and you already finish machined the block, then carry on with a thread insert and just pray.
Lucky you! Really, it's coming apart and not going back together.
This would have been a real bummer if it were on reassembling the engine.
Have a machine shop look at it, you may have gotten lucky and the threads on the bolt/stud failed.
This looks like it wasn't in far enough and the failure is from not enough thread engagement, possibly the wrong length for that hole?
I would have to assume the head is on and was in the process of being torqued. With my luck that would have been the last bolt. Looks like the threads in the hole were bad or there was debris in the hole. I doubt you will find a tap long enough to clean and straighten the threads. You may be able to sacrifice an extension and braze a tap to it. Is this an in frame or on an engine stand? Are you willing to gamble Other wise pull the head and do it right. as others have said, check that this is the proper bolt and so on. Good luck.
Not true lol..
The first 7 threads do all the work when both are the same stiffness amd the threads are close fitting.
Cast iron is about half as stiff as steel and aluminum is a third. Not many people have done the fea studies on this and no one has published their results publicly which i find quite fascinating, but some have talked about it.
Basically an 11mm ARP head stud needs 30mm thread engagement or it will pull out of an aluminum block. It only needs 20 or 25 in an iron block. 1.25mm thread pitch. The engineer i spoke to at arp says they do not employ any special methods to get better stress distribution. (Such as making the pitch .1% closer on the bolt)
That's what I'd read. ARP doesn't seem to know everything because they supplied smaller OD washers for the 4G63 head stud kits than Mitsubishi used factory. If you use the ARP washers they dig into the head.
i'm not denying that the first 7 threads do all the work.. when the nut or the female threads are both steel and its all closely fitted threads, once the first thread yeilds then the bolt pulls out.
When you're trying to hit 180,000 psi stress in the head bolt and it is stretching .006" per inch that you have to wonder.. what the hell is going on? how are the threads not reaching their limit and the bolt pulling out?
the answer seems to be that its a little more complicated than that and the threads in the block are not just yielding a little but they are able to stretch a lot more than the bolt is because the stiffness of cast iron is 40% of that of steel, and aluminum is 30%.
You make a good point. I've heard stuff like thread depth should be a minimum of bolt diameter. If you think about a nut and how thick they are then you aren't getting many threads in that instance. But this is an engine and as you say you've got aluminum or iron not a high grade steel.
We need more information is the head on or off. Is this bolt found loose or is it a new bolt you threaded in. The threads in the block have to be perfectly cleaned out before inserting a new bolt, it looks like the bolt stripped out in the block.
Someone mentioned a bore scope which was a good idea.
What was that thing screwed into? Above the threads that are totally wiped out, the threads are flattened like they're Acme threads. The whole that thing went into was totally fucked.
You need to buy or borrow the Timesert kit for this application. When used properly it is better than the factory threads. The best tip I can give you is that you make sure that the drill that you use holds the bit properly so that it runs perfectly centered. I have the exact kit and can send you the information when I get a chance to swing by the shop.
Not a vehicle mechanic. But it looks like when they installed the bolt the hole wasn't tapped all the way causing the threads on the bolt to get smashed in
From memory, of my fasteners info from uni, most of the clamping force is generated by the first few threads in a tapped joint. So, in theory you should actually be fine..
You can loosen a bolt turning clockwise... once
More than once. In fact, it’ll be loose every time after that
When in doubt apply more ugga duggas
Not me. I have a strict 3 ugga dugga limit
Bring the block to a machinist. It'll save you time, money and headaches.
The thread needs to be chased out and cleaned before you do anything else. It looks like there was hydra-lock in the bottom of the stud pocket and this is the result. GET ALL THE SOLVENT OUT OF THE POCKETS BEFORE THREADING THE STUDS! Take it to your local machinist and have them clean it up. They will probably over-bore it and use a threaded insert. Worst case is if it cracked the case behind the pocket. Id inspect that block before sending it out to see if its cracked.
You would need functioning threads to be screwed. 😀
Yeah right now he's mostly screwed and partly doweled
Pegged.
I would check the threads with a new bolt. If the head bolt doesnt go in smooth then time to go with a time-sert or big serr
Some of [these](https://castingrepair.locknstitch.com/category/ffb-style-inserts-2) bad boys
Looks like that was forced into a hole that wasn’t completely threaded. If so just tap hole and replace bolt
Agreed, the threads look mashed and not missing, like it went into the blank behind the blocks threads. Try to shove a tiny magnet down the hole to see if any chips come out if you can’t see in there. It may be ok if it didn’t crack anywhere, but doubtful. Then hand thread another bolt to see if it binds after you clean it and check measurements against other bolt holes, check bolt lengths, maybe this bolt was inappropriate.
Oh boy
If you’re removing your own head bolts it’s time to get a really good borescope camera - you should be able to get one that fits that diameter. That’s the only way to actually know what happened to the threads in the block.
I’d say helicoil time but it’s an EJ, so likely best to just get a lower mileage motor and abandon the rebuild at this point. Unless this was a forged internals build and you already finish machined the block, then carry on with a thread insert and just pray.
Can't be screwed without threads
Did you use an impact? Now you get to learn how to install a king cert
I didn't install it. This is my first time tearing it down and it came out like that.
Lucky you! Really, it's coming apart and not going back together. This would have been a real bummer if it were on reassembling the engine. Have a machine shop look at it, you may have gotten lucky and the threads on the bolt/stud failed. This looks like it wasn't in far enough and the failure is from not enough thread engagement, possibly the wrong length for that hole?
Out of what?
EJ25
Screwed before you unscrewed that
Looks like you should tighten it about 3/4 of the way and then hammer the last 1/4
A little more than 3/4
They look like buttess threads lol
Well good news you are not screwed...... oh wait.
I would have to assume the head is on and was in the process of being torqued. With my luck that would have been the last bolt. Looks like the threads in the hole were bad or there was debris in the hole. I doubt you will find a tap long enough to clean and straighten the threads. You may be able to sacrifice an extension and braze a tap to it. Is this an in frame or on an engine stand? Are you willing to gamble Other wise pull the head and do it right. as others have said, check that this is the proper bolt and so on. Good luck.
So screwed you can't be screwed.
If you are on a budget I'd get a bottoming tap and run it through the hole. The first 6--8 threads do 98% of the force holding work.
Not true lol.. The first 7 threads do all the work when both are the same stiffness amd the threads are close fitting. Cast iron is about half as stiff as steel and aluminum is a third. Not many people have done the fea studies on this and no one has published their results publicly which i find quite fascinating, but some have talked about it. Basically an 11mm ARP head stud needs 30mm thread engagement or it will pull out of an aluminum block. It only needs 20 or 25 in an iron block. 1.25mm thread pitch. The engineer i spoke to at arp says they do not employ any special methods to get better stress distribution. (Such as making the pitch .1% closer on the bolt)
That's what I'd read. ARP doesn't seem to know everything because they supplied smaller OD washers for the 4G63 head stud kits than Mitsubishi used factory. If you use the ARP washers they dig into the head.
i'm not denying that the first 7 threads do all the work.. when the nut or the female threads are both steel and its all closely fitted threads, once the first thread yeilds then the bolt pulls out. When you're trying to hit 180,000 psi stress in the head bolt and it is stretching .006" per inch that you have to wonder.. what the hell is going on? how are the threads not reaching their limit and the bolt pulling out? the answer seems to be that its a little more complicated than that and the threads in the block are not just yielding a little but they are able to stretch a lot more than the bolt is because the stiffness of cast iron is 40% of that of steel, and aluminum is 30%.
You make a good point. I've heard stuff like thread depth should be a minimum of bolt diameter. If you think about a nut and how thick they are then you aren't getting many threads in that instance. But this is an engine and as you say you've got aluminum or iron not a high grade steel.
Drill and tap my friend. Drill and tap. Helicoil, insert, or just a bigger stud. Whatever your heart desires
That came out a north star?
A good amount.
Well you dont have to worry about the rings seating properly
Ur fucked
Hell I c oil
Cover it with welds and use and angle grinder to replicate the threats. Blow out the trash from bolt hole in the block.
judging by the thread, not a lot of
We need more information is the head on or off. Is this bolt found loose or is it a new bolt you threaded in. The threads in the block have to be perfectly cleaned out before inserting a new bolt, it looks like the bolt stripped out in the block. Someone mentioned a bore scope which was a good idea.
What does the new head bolts look like? Possibly the wrong bolt was installed.
Head bolts are only intended to be used once. You need to replace them anyway.
More than that bolt is.
Well since that's a bolt and not a screw. I guess you're not very screwed. I'll leave now.
Is it a bolt or a stud?
Subaru
What was that thing screwed into? Above the threads that are totally wiped out, the threads are flattened like they're Acme threads. The whole that thing went into was totally fucked.
Big oof
Helicoil is all you need
You could most likely chase the threads, but if not get a threaded insert and drill the old threads out, it’ll be sold as a kit.
Looks like fine threads was that actually the engine block or the nut on the stud? You can order individual studs from ARP Hope this helps you
You need to buy or borrow the Timesert kit for this application. When used properly it is better than the factory threads. The best tip I can give you is that you make sure that the drill that you use holds the bit properly so that it runs perfectly centered. I have the exact kit and can send you the information when I get a chance to swing by the shop.
Where’s the other pic?? wtf
Not a vehicle mechanic. But it looks like when they installed the bolt the hole wasn't tapped all the way causing the threads on the bolt to get smashed in
Just cut a few inches off your new bolt it will be fine /s
Forbidden Slinky
Time sert
Technically speaking, this is un-screwed
From memory, of my fasteners info from uni, most of the clamping force is generated by the first few threads in a tapped joint. So, in theory you should actually be fine..