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broken head bolts in block help!!!!!!!!


Guest Anonymous

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Guest Anonymous
:evil: Have a problem snaped to head bolts in block and everthing that i have done just does not seem to work even tryed those expencive drill bits really avoiding taking the block to the machine shop if any sugjestions i would be very greatfull i need help!!!!!!!!!!!! Thanks
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If you can, drill all the way thru the piece of bolt left in block.

 

Try an find some penitating oil called KROIL , use it and let it sit and soak in, use a solid punch and SQUARELY hit top of broken bolt to try and loosen piece of bolt. (WEAR SAFETY GLASSES)

Reapply KROIL and repete process.

 

With good drill bits you should be able to drill thru stud. Take your time and try to drill dead center of bolt. Drill as big of a hole that u can, then try an easy out. (NOT A CHEAP ONE)

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Guest Anonymous

Thanks ill go to the speed shop and grab some of that oil hope it works this has been aproblem for awhile now it6 drives me nuts seeing my Z just sitting once again thanks :twisted:

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Guest Anonymous

that is one of the problems that im having on one of those head bolts i have a broken EZout in it it snaped flush with the block the other head bolt has a snapped titanium bit in the center Sorry should of explained that in the beging man do i have problems if you guys can come up with something for that. Wow i would worship the Z gods forever&ever&ever etc... Thanks for the help i want my car back

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Doh, that sucks. The titanium bits are only coated. You can try a cobalt carbide bit and drill that and the ez out, I know Ace sells them. It has to be carbide though. I used a carbide dremel bit to get an ez out before(manifold stud) but ended up having to heli-coil the hole after I got it out.

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Good suggestions all... Once you get it sorted out with an EZ out in the bolt, I suggest putting the bolt through a few heat cycles witha propane torch, and cooling it rapidly with something like WD-40. I found that the expansion and contraction of the bolt with heat allowed the WD-40 to work its way down the thread. 2 or 3 heat cycles soaked down with WD and I removed a couple broken ones no problem. (with vice grips since I had something to grab onto)

 

Worked for me anyway.

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Guest Anonymous

how much i need a new one i got those bolts out and discoverd that the block is shot theres a hairline crack going from the bolt to the cylinder and to top it off i moved the piston's up and down and there is a crack in the front cylinder wall i need a new one dam hope its not to much im not rich thanks

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Guest CalgaryZed

When on of mine snaped, rather then risk breaking an EZ out , I drilled the stud out and used a helicoil. I am not sure how strong does coils are but it was an easy solution.

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Some people dont like them in important places, but heli coils rock IMO. I had them put on my heads (aluminum though). There is stuff stronger than heli coil but dont recall off the top of my head, have to ask around on what kind of TQ they could stand.

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Guest Tempe_Z

I'm sure the helicoil threads are at least as strong as threads cut into a cast iron block are, considering they're made of 18-8 stainless according to the helicoil tech info on their webpage. (i.e. 302 stainless) Threads in cast iron are typically 2x the diameter in thread depth vs 1.5x or 1x the diameter in harder steels. I think that alone should satisfy any concerns you might have about the strength. They're used in Aviation quite often, and are Mil specced too.

 

Definitely the way to go in aluminum parts though, in fact I can't think of any place on a Z or any other car in the aluminum theads (including the cylinder head) where I'd hesitate to use one vs bolts straight into threads cut into aluminum.

 

Sure, you'll pay a bit up front for a set for the appropriate install took but given the amount of 8x1.25 fasteners on a Zcar, that's a good size to keep plenty of em on hand in. Without the installation tool, the inserts are pretty reasonable and I say use em whenever you can, especially on stuff that might see a good bit of abuse and frequent assembly/disassembly. If it's a relatively low stress area (such as the valve cover bolts for instance) you could red threadlock them in and be pretty safe in the assumption that you'll never need to pull one back out. If you don't mind ordering them you can get helicoils in materials like Inconel too or with a dry film lubricant (molybdenum disulfide), probably expensive, probably overkill, but maybe not a bad idea on for say exhaust manifold fasteners.

 

Another good reason is that stainless interacting with a bolt is less likely to experience galvanic corrosion most of the time and with the heat cycles from applications such as the intake/exhaust studs on the head this is another good spot. If you use stainless bolts with helicoils in this spot you generally won't have the disassembly problems that regular bolts in the aluminum have plus it looks nice. That said, a little bit of anti-sieze is always a good thing too whether you're using a heli-coil or not.

 

No I don't work for Helicoil. I just think they're about the best damn thing since sliced bread in most applications especially where you're bolting into aluminum provided there's enough material surrounding the hole to install one. Anyways hope this is all the info on these little buggers anyone could ever possibly need and then some. If not go to their website.

 

http://www.emhart.com

 

There's also Recoil inserts, I've used them as well and they work great too. They're made by fairchild fasteners and are more aviation related in background as a company (compared to black and decker owning helicoils). Of course if you have the right application for it the ringlock/rosan style inserts are really nice too, but they're friggin expensive.

 

http://www.fairchildfasteners.com

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Definitely the way to go in aluminum parts though, in fact I can't think of any place on a Z or any other car in the aluminum theads (including the cylinder head) where I'd hesitate to use one vs bolts straight into threads cut into aluminum.

 

It is especially a blessing in tight spaces, like large diameter header primaries threading into aluminum heads :shock: That is mostly why I love them so much, makes threading by FEEL easier and much safer, especially when installing headers in a car with crappy clearance and holding the header in place while trying to locate the proper thread and hold a gasket all at the same time!

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Guest Tempe_Z

Well I got curious after you mentioned some people don't think they're as strong, and did some more research. Some of the PDF's from the fairchild fasteners page show tests they've run in materials such as aluminum and steel assuming a 37000psi shear strength. Cast iron goes anywhere between 15 and 45000psi depending on the carbon content. I'm guessing the gray cast iron in an engine block is somewhere toward the bottom of that. 304 Stainless has a sheer strength in the 58000 psi neighborhood.

 

In the tests they were running on aluminum it took a 14000 plus pound load to pull the fastener out (3/8" by 16 thread pitch) This is pretty close to the size of the 10x1.5 of the head bolts on an L series engine. In pretty much every failure the newly threaded area outside the insert itself pulled out rather than the insert failing and pulling out or the bolt breaking (they were using grade 5 bolts). I'd say even using them in the block for the head bolts they're definitely going to hold up better than the stock cut threads. The design of the inserts also tends to distribute the load more evenly along the threads compared to a normal threaded hole, whereas a cut thread tends to concentrate more of the load toward the head of the bolt and then less the further in the threads go.

 

So back to the original post in the thread, I'd say if you need to drill out an old head bolt and replace it with a helicoil type insert, you're only going to make it stronger than it was before. Hell I'd probably do all of em, probably will next time I'm in there on my engine in fact.

 

They're just magical little suckers.

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I dont know that its a strength issue, but since its a thread on a thread I imagine there is a slippage concern, as for the reality of the issue I dont know how big "problems" are or if it is just prejudice against getting a possibly abused block. I have seen people complain about finding helicoils in thier new crate engines, like in the starter area, etc

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