Removing studs

[BBH]

The rear manifold stud (nearest the exhaust outlet) broke off about 1/4 inch inside the block, and I will need a righthand extension for my power drill to remove it. (My engine is on my boat, and access space on the port side is about 7 inches.)

1. Where or from whom can I get the best righthand power drill extension that won't cost me an arm and a leg?
2. How can you maintain a straight-in position with the drill bit to avoid stripping the stud threads in the block?
3. For a 3/8 stud, what size drill bit is best, a 1/4 bit?
4. Can an Easy Out bit be used? (I have heard good things and bad things about Easy Out bits.)

After removing the nuts from the head studs, is it feasible to remove the head before removing the studs, to better apply penetrating oil to the stud threads before removing the studs? (Don Moyer's Overhaul manual removes the studs first.)

[Davis Modlin]

In the rebuild that I'm finishing right now, I removed the head and then the studs

Davis

[Don Moyer]

BBH,

It's extremely unlikely (practically impossible) for the last few threads of a hardened stud to hold so tightly as to cause the stud to fail that far below the surface of the block. Therefore, before doing anything else, please inspect the end of the stud that came out of the fourth hole. My guess (hope) is that you will not find a clear fracture zone across the end of the stud, but rather a round and corroded end to the stud.

If, on re-examination, you do find the above condition to exist with respect to the condition of the end of the stud, all you have to do to clean out the forth hole is take a small screwdriver and use it as you would a "star" drill, tapping and rotating it into the hole to clean out the calcified corrosion, which is all that's blocking the hole.

If, on the other hand, there is a small piece of the stud broken off inside the hole, it's best to drill out the remaining piece of stud using a factory fresh 1/8" drill bit, working up to 5/16", and then carefully dressing up the threads with a coarse-threaded 3/8" tap.

I strongly discourage the use of an "easy out". Contrary to what the name would have you believe, an easy out is anything but an easy way out of your dilemma. At least in this application, an easy out is clearly the work of the devil. They have a 100% failure rate in actually being able to turn a broken stud out, and (more importantly) in at least 50% of the cases reported back to us, the easy out broke, posing a far more difficult situation than before.

There's nothing really wrong with trying to remove a head without removing the studs, but we continue to recommend removing the studs before applying any great amount of force to remove a head. It's too easy to crack a head or to damage the block by going to a bigger and bigger hammer.

Best regards,

Don Moyer

[BBH]

Removing studs

It seems that I broke off a head stud -- there are six threads remaining on the stud, which has what I would call a clean fracture -- while removing the head nuts, in preparation to removing the head, which I haven't done yet.

How long is a head stud? (I have an early-model engine, and would like to have some idea on how far down I will have to drill to remove the remains of the broken stud.)

[Don Moyer]

BBH,

The overall length of a standard head stud is approximately 2 - 9/16". The threaded part of the stud is approximately 1/2", and will contain 7 to 8 threads. If I understand your situation correctly, the stud that you believe to be broken still has 6 threads showing, which means that only two threads (maximum) would be missing.

It's extremely unlikely (practically impossible) for the last few threads of a hardened stud to hold so tightly as to cause the stud to fail that far below the surface of the block. It's far more likely that the end of the stud corroded away, leaving behind a hardened calcified substance within the lower part of the hole.

If this is the case, all you have to do to clean out the hole is take a small screwdriver and use it as you would a "star" drill, tapping and rotating it into the hole to clean out the calcified corrosion, which is all that's blocking the hole, and then dress up the threads with a coarse 3/8" tap.

Best regards,

Don Moyer

[BBH]

Removing calcified deposits

I have been using a small screwdriver as a substitute star drill to clean out two of the manifold stud holes in the block, as recommended, but progress seems extremely slow. It feels that I am tapping against hardened metal rather than calcified material, but I'll keep at it. (What else can I do?)

I intend to buy new manifold studs once I get the holes in the block cleaned out and my manifold back from the machine shop, where they are drilling out a frozen stud and a broken-off 3/8 exhaust flange bolt at the exhaust end.

How far in the block do I have to clean out the two calcified holes to accept the new studs?

As stated in Moyer's Overhaul Manual, the manifold holes in the block extend into the cooling (water) jacket , but is it necessary to clean these holes all the way into the water jacket? (My center manifold stud hole in the block is open and I can insert a piece of wire into this hole, all the way across to the water jacket side plate.)

[Don Moyer]

BBH,

Based on your earlier measurements (the stud hole being open to approximately 1/4" below the surface of the block), you must have started out with a section of stud/residue remaining in the hole of approximately 1/8" in length.

My best guess is that your biggest problem is the limited space you have to do this difficult work (7"). Here are a few things that come to mind:

1) Have your local machine shop make you a small tool consisting of a short length of hardened round stock (approximately 1 1/2" long, and between 3/16" and 1/4" in diameter), sharpened on one end and with a flat washer welded on the other end. A piece of the chuck end of a drill bit works well. Such a tool will enable you to use most of your 7" access to swing a medium sized hammer as you continue to work the hole. The purpose of the flat washer is to prevent the tool from slipping all the way into the hole when you finally break through - which is the optimistic point of view.

2) Seven inches of limited access must be a major problem for you in servicing other important items on this side of the engine, like the carburetor, fuel pump (and heaven forbid that you had to adjust your oil pressure or remove your valve cover). My second suggestion therefore is to cut a generous access panel to expose the area in which you are working. Many of our customers are providing attractive teak framed access panels for themselves around their engines, which ends up saving countless hours of time and makes essential service work much less frustrating.

3) Depending on what's outside of the engine compartment where you are working, a scaled back approach to (2) above would be to hole saw a couple of 2" holes directly opposite the defective holes. This would enable you to use a small drill in the hole, which should make quick work of creating a pathway through the blockage, after which the "star drill" approach should be much more effective.

With regard to how important it is to clean out the holes all the way to the water jacket, it's critically important. There simply isn't enough cross section of metal in the area of those holes to accommodate a tap (even a "bottoming" tap) to dress up the threads, and even if you could, there wouldn't be enough threads to support the stress of 25 foot-pounds of torque.

I strongly urge you to take a deep breath and continue your work with the most positive attitude that you can muster. My wife always pounds me into the ground when I dare to tread on this sacred ground, but I sincerely believe that work like you're involved in must resemble what women experience in the process of giving birth. Years from now, and long after you forget the pain, you'll benefit from seeing this job through.

Best regards,

Don Moyer

[BBH]

Removing studs, calcified deposits

Don Moyer,

Thanks for the pep talk on sticking with removing calcified deposits. I am still at it.

The two manifold stud holes in questiion in the block are the front and rear holes. I can now run a 3/8 coarse tap 3/4 inches into both holes. but both holes are still blocked after that depth.

Using a mirror and flashlight, I can see into the front hole and see the end of the blockage, at what seems to be a shiny surface, which looks like clean metal. Can calcified deposits look like metal after their ends have been worked over with a flat-blade screwdriver (the star drill approach), or do the deposits always have a dull sheen, not bright?

Another problem has arisen. When I insert an ice pick in the front manifold stud hole, I can insert it 1-3/4 inches (from the side of the block) into a break at the bottom of the hole. I can also do the same, except for 1-1/4 inches, in the rear manifold stud hole. It seems that, in both cases, I have broken through the stud wall into another chamber. Is this the valve chamber possibly, or the water jacket, or nothing to worry about?

Thanks for the suggestion to cut out a panel for easier access to the manifold side of the engine, but the ice box is there, and I am leary of removing any of that. (When I replaced the starter recently, with a Delco, I had to cut out a portion of the side panel of the sink for access to the lower bolt on the starter. The starter side of the engine has even less access space than the manifold side.)

[Don Moyer]

BBH,

It sounds like you've clearly broken into the water jacket with the ice pick on both holes, and at 3/4", the tap itself must be past the depth of where the studs originally extended.

Please be careful not to use too much force when the tap bottoms out, because you could easily damage the outer threads. In fact, I would start running a new stud into the holes to check on depth and fit. If you're using a bottoming tap, you may indeed be deep enough (referring back to one of your earlier questions about having to get all the way through to the water jacket).

At this point, if you decide to go deeper, I would start using drill bits in the jaws of a small vise grip to work on the holes (starting with a 1/4" bit, and working up to a 5/16" drill bit). By the time you're able to get a 5/16" through the hole, you should be able to advance your tapered 3/8" tap,
but again, don't use too much force on the tap.

Don

[BBH]

Removing studs

Don Moyer,

So you are not under the wrong impression, I didn't break through the walls of the front and rear manifold holes in the block with an ice pick. While trying to work out the part of the stud still in each hole with a small flat-bladed screwdriver, I could feel that there was a small hole in the bottom of each stud hole wall. I then used an ice pick to try to measure the depth of the holes, hoping that I would not enlarge the hole unnecessarily, which I probably did to some extent. Perhaps I was the one that broke through the walls, but if I didn't, I have a theory.

My theory on the stud hole walls is that the walls were broken through some time in the past and let salt water corrode the middle of the front and rear manifold studs. Then when I tried to remove them, they broke off at their corroded points, and the part of the studs still in the block is hard metal, not calcified material.

As it is, the above is neither here nor there, but I am curious: Is it possible that the studs could have been corroded in their centers but not at their water jacket ends, or is this too far fetched?

I have ordered new manifold studs from Ken, which leads me to my main question: With the new studs, is it okay to use Permatex Aviation Form-A-Gasket on their block-end threads, or should I go with Locktite Stud-Locker? (I am leary of Locktite on the new threads because of the possible need for heat if I have to remove them in the future.)

[Don Moyer]

BBH,

There's no need to be leery of using Locktite. If you ever do have to remove them, it won't take very much heat. In fact, if the studs feel rather loose in the holes, I recommend going directly to JB Weld. In my opinion, it's more important to insure that you'll never have to remove these studs again than it is to worry about facilitating their removal.

Regarding your question about someone breaking through the end of the two stud holes in the past, I must not have been clear in our earlier discussion. All three of the manifold stud holes normally enter into the water jacket, so it's very common for the ends of the studs to be missing a few threads due to being corroded away. We sometimes find them with only 2 threads left.

Best regards,

Don Moyer

[keithems]

i have a late model a4, and i broke a thermostat housing stud about .25" down into the head. [don't ask....]

i assume i have to drill it out and replace it.

if so, which of the mmi repair stud kits should i get -- ktas 04 446 or oblk 06 446 -- and what is the difference?

is there any other way to fix this problem, at least for the summer? for example, could i fill the hole with jb weld and then drill and tap a shallow hole and insert a short stud to hold the thermostat housing only? or could i just widen the existing hole and jb weld a short stud in there to hold the thermostat housing?

i rarely need the engine for more than 1/2 hour to get in and out of the marina, though i was hoping to go on a longer trip this summer.

thank you in advance for your help --

keithems

[keithems]

further clarification:

the stud is broken off about 1/4" below the top of the head, not the block.....it's the stud that holds down the thermostat housing, the one closest to the flywheel end of the head / block -- just above the port for the temp sensor...

how this happened....

girlfriend offered to loan me her deceased dad's beautiful snap-on torque wrench. my a4 runs well, but because i see a fair amount of white smoke / steam in the exhaust, i decided to re-torque the head bolts to 30-35 foot lbs.

but -- dummie me, i had never used a torque wrench before, so i expected it would skip -- not just click -- when i reached the torque i had set.

so -- dummie me -- i overdid the above nut and broke that stud. i then tried to remove it with a stud extractor, but that only cut it off about flush with the head. i then drilled a few holes in it and pounded in some e-z outs; a few of them fractured when i tried to turn them [i know, i know, but i hadn't gotten home yet to read where don says to avoid them -- dummie me]

anyhoo - the result now is that the stud between block and head seems to be quite secure and unmoving; there's only a shallow hole in the top of the head, and no way at present to secure the thermostat housing. frankly, i think if i could do that, the block and head will stay together for the rest of the summer and in the fall i'll remove the head and hopefully enough of the thermostat stud remnant will be sticking out of the block to be stud extracted also; i just don't want to do it now, if you understand.

therefore, i'm more than willing to get one of the stud repair kits -- but which one? -- and should i get into the block at all if i don't really have a problem there with slipping studs, etc.?

-- if anything -- given the gallons of pb blaster i've already shot into the hole with no stud movement, i think that stud may have been jb welded in there previously by the p.o.

i also just read tonite on the mmi site about the perils of attempting to drill and tap a straight hole with the motor in the boat and the head still on it...

therefore, i await your response and advice.....


thank you, as always...

keithems

[ILikeRust]

I know you don't want to hear this, but I would remove the head.

You're going to have a hell of a time trying to get that stud out of there when it's down in a hole in the head - and you run the risk of inadvertently doing damage to the head while you're banging, drilling, etc., on that stud.

I would buy the Snap-On stud remover - available from Moyer - and remove all the head nuts, then carefully extract the studs using that Snap-On tool. It's expensive, but it is without a doubt the best way to get those studs out.

Also - forget the PB Blaster - use Kroil. I'm not a paid spokesperson, although I should be, for all the cans of that stuff I've probably sold. I just know for a fact that it works better than PB Blaster or any other commercial penetrating lubricant I know of. In fact, a machinist magazine did a "scientific" (or at least a reasonable attempt at a standardized "scientific") test and found Kroil to outperform everything else. The only thing better was a mix of 50/50 acetone/ATF - which you of course could mix up yourself, but it doesn't keep unless you seal it tightly in a metal can, because the acetone will evaporate quickly.

Anyhow, I would get all the studs out, except that last broken one, and then carefully remove the head. You will then be left with about an inch of stud sticking above the block that you can work on. If you're careful, you can grab it with a big pair of vise-grips and apply some torque. Hit it with heat from a torch, squirt it with Kroil, wait, let it cool down, hit it with Kroil, apply some heat, apply some torque, wait. Be very patient. It might take you a couple days, working 20 minutes at a time, applying heat, applying Kroil, applying a little torque, until it finally breaks free.

It is possible for that you can snap that stud off, and then you'll really have a problem. So take your time and be patient.

How do I know this is the approach I would take?

Because I did the same thing you did - or at least a very similar thing.

See this thread beginning here. At that point, I already had removed all of the head studs, using the "expensive, but worth it" SnapOn tool.

I really can't think of a good way to get that broken head stud out without taking the head off, especially if it's down below the level of the head.

You don't have to take the engine out to take the head off.

[jpian0923]

Bills advice is the ideal way to handle it.

But, You could drill it. Start will the smallest bit possible. (buy the best bits you can find)

Try to get it centered. Graduate to larger bits taking care not to drill the coarse threads in the block.

Once you have hollowed out the stud you should be able to bend it in on itself and twist it out, or, twist it in.

That stud goes all the way into the water jacket. Leaving it in the water jacket for a season shouldn't be a problem.

You can retrieve it later by removing the water jacket side plate.

Clean up the block threads with the appropriate tap and put in a new standard size thermostat housing stud.