Drilled out stud holes

[Richard/Ca]

I would like to thank every one for the help on the stud hole that was drilled through into the water jacket. But I still would like some ideas on how to get the old stud threads out of the hole.

[dumb person]

Place cylinderhead over holes and use undersize drill to drill out most of old studs. Strip of metal with cuts made in it filed to match the threads, used like a brush around and around to clean out the threads a little. Seen it done once if that helps

[Bob C]

If I read your original post correctly you said you could stick a
28/64" drill in the hole. 28/64 = 7/16 which is the size of the
stud so there should not be any threads in the hole. You would
need to install a helicoil.

Bob

[Jim Brierley]

Like dump person, I use a head as a guide and a sleeve to keep a smaller drill centered. Sometimes you can then use an easy-out, sometimes a heli-coil is needed.

[CA Victoria]

If you can find someone in your area using the Lock-n-Stitch (Turlock Ca) method, they make a thread repair with a blind insert, where as the heli-coil is just a thread repair. This type is used to repair the thread and seal the hole.

[Richard/Ca]

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Thanks Guys for the great ideas on getting the old threads out. I will try most of them until I can get them out. But I should do like Purdy Swoft says an ( leave it to the professionals). A statement I hope does not come back to haunt me later. For I am one of those people that has to try to do it himself. Oh! Bob C I thought 29/64 was the size of the drill used like that is no big deal 1/64 of an inch.

[Zeke...PA]

I have had good luck (at times) using left hand drill bits working up in size till it backs out the remaining threads. Of course you have your drill motor set for reverse. Zeke

[Bob C]

The point I was trying to make is if you can put a 29/64" drill bit
in the hole then the hole is bigger than the 7/16" outside diameter
of the stud.

Bob

[Richard/Ca]

OK Bob! Sorry Bob I was not trying to upset you I was just asking if the 29/64 drill was the size of the hole before it was threaded originally. I read your thread again and have a better understanding of it. Thank you for your help and all help is highly appreciated and welcomed. Richard

[Bob C]

Richard, I'm not upset. The size hole you need for a stock 7/16-14 stud
before you tap it is a letter U (.368") drill bit, a little smaller than a 3/8" (.375). If your hole is 29/64" (.4531") then you are .0851" oversize already.


Bob

[Richard/Ca]

Originally Posted by Bob C

Richard, I'm not upset. The size hole you need for a stock 7/16-14 stud
before you tap it is a letter U (.368") drill bit, a little smaller than a 3/8" (.375). If your hole is 29/64" (.4531") then you are .0851" oversize already.


Bob

OK Bob
After further review I have apologize to every body involved with the issue. I went out to my garage and very closely look at the drill bit It was in fact 23/64th not 28/64th. I want to thank you and all the other that help get me straight on this matter. Wish they would mark the drill bits some where so they would not get messed up in the chuck. Richard

[kp]

Left handed drill bits are great ,as Zeke Stated above .I bought CHeap ones at Harbor freight and sometimes they drill in a bit and bring the broken stud right out,as stated above you have to have your drill in reverse ,other times I use an "ease out" after drilling a hole in the middle of the broke off stud,but tapping it with a hammer and soaking with PENETROL(or some other good penetrating oil ) before hand helps . all mentioned in the above post.

[Bob C]

Richard, Glad you got everything worked out. 23/64" is slightly smaller
than the U drill bit so you are good to go.

Bob

[Richard/Ca]

That's OK Bob I really appreciate all the help I can get on the FordBarn.

[d.j. moordigian]

Richard,
Let us know how the repair goes & the outcome.

[Paul from Maine]

Originally Posted by Richard/Ca

That's OK Bob I really appreciate all the help I can get on the FordBarn.

Mac's sells oversize studs, so if you mess up and drill into the the block threads its no big deal. Just drill and tap the hole for the oversize stud. I ordered a spare when it happened to me so that if it happens again in the future I don't have to wait a fortnight for Macs to deliver.

[Bubby Sharp in KY]

Richard/ CA , To remove old stud place a 7/16" flat washer and nut on top of old broken stud and weld to stud , let cool then remove by rocking the nut back and forth intill loose enough tho remove . Some penetrating oil will help also . I just removed a stubborn 1/8 pipe plug ( the one on the side of the block that goes to the oil pump ) using this method . NO damage to block . Bubby Sharp in KY

[Tom Wesenberg]

I try the washer/nut welding trick as Bubby mentioned, and if that doesn't work then I start with a 1/8" bit and drill down the center of the stud. I keep increasing the size of the bit until I can just start to see the edge of the thread in the block. I then use a dental pick or similar tool to pick away at the threads. I can usually get down a couple of rows so I can try a tap. I turn the tap just a little and it grabs some of the thread. I then remove the tap and pull out any more thread that I can, then use the tap again. Keep going until all the thread is out. So far I haven't had to use an oversize stud nor helicoil.

[roddyb34]

I have just removed the head studs from our engine and succesfully broke 3 of them,i tryed the weld method ,no success ,so drilled with small to large drill,then tapped out the stud remains ,but gees you have to be dead on ,the end result is a little of the stud remained on one side ,not much but enough to egg the hole slightly ,i was able to get the remaining shiny bits out ,rerun the tap down and refitted studs even though slighltly loose for a bit they tighten in deep and firm , i was thinking of doing a test tension run minus gasket to try ,i can get them helicoiled but wondered if should go without ,maybe add some suitable loctite ,surely theres a lot of daggy threads that survive,,

[CarlG]

I was thinking of dipping the stud threads in JB Weld or something before screwing them back in the block to make for a tighter fit on loosy-goosy block threads.