WAS on the home stretch assembling my 8ba flathead for my '51 Tudor. One of the head studs is not perpendicular to the deck. Probably due to a thread insert that was not installed perfectly. This hole has a common "Ford Crack" from an adjacent coolant hole, which makes me hesitant to bang the stud into column. I'm really at a loss at what to do, could really use some ideas. Thanks.
Uh, fix the insert if that is the culprit. Removing heads from a studded flatty is tough enough without a crooked stud.
I would either get a shoulder screw that you can thread into the block, or machine a pin that has a running fit with the minor diameter of those threads. Then, I would put either of those things in the hole in question, and check it against a precision square that's placed flat on the deck. It may save a lot of time and effort to make sure that it is indeed the threaded hole being out of square with the block, and not the stud being bent. I notice that the studs are ARP, and probably new, so they aren't likely bent. It's worth checking anyway though in my opinion.
I agree in a perfect world fixing the insert would be the ticket. The misalignment is not quite as bad as the first pic seems to show, some additional pics attached. The stud can actually be started with the head on and threaded in a bit. A bunch of measurements taken seem to indicate that if the stud hole in the head is opened up by .0125 the stud should be installable with the head on. It is a bummer running into this at this stage of the engine build, just trying to find the least invasive fix.
Are you seriously considering opening up the head? The least invasive fix is fixing the threaded insert. Opening up the head to fit a misaligned stud is hack work. You could have had this fixed in the amount of time it took to, take pictures, post this thread, and make these replies justifying hack work. Do it right.
Oh, I missed that part @Hitchhiker I didn't see he was planning on opening the hole in the head. My wife says I have a hole in my head, I sure wouldn't want to make it bigger.
I was actually kinda shocked at your reply. Because i know you build REALLY nice stuff. That makes more sense now.
I'm willing to learn, given that this engine is assembled, that it is my home shop, not a machine shop, how would I do it right, what tools needed, and as quickly as you mention? Understand I am not in arguing with you, I'd like know how to do this right. Thanks.
Make some calls. Take it to somebody who can fix it. P.S. The boat has sailed and Elvis has left the building but you still need to know this going forward. Ford used a slightly undersized head bolt/ stud hole. This made the bolt or stud fit very tightly. The stud or bolts went through water and the tight clearances helped seal. A common mistake flathead V8 builders make is running a standard tap through that tight hole. The end result is water leaks out the stud/ bolt holes. It’s not that easy of a fix. Sealers help but with mixed results. It’s always a good practice to preserve the original factory threads. An old head stud or bolt can be grooved and made into cleanout, never a tap. I see you have inserts. I saw some Flathead thread insets advertised as a set on FB and I thought....UhOh...... I wonder if those are really compatible with a Flathead for the reasons stated above. I recommend expert help on this. I have seen repairable problems spiral into a trip across the scales. Expert help......I mean really expert help that know these engines. Not Gus the local Three Fitty guy. Make sure all of the inverts are strait. Then there’s the potential seal problem. This is why I think expert service would be wise here. Again, goofy stuff like this is like the LabreahaTarpits. It draws you in. The next thing you know, you have. Figure 8 shaped hole with broken ease out in it. Then you have a real problem. Sometimes you have to know when to fold them.
Sure looks like a HELICOIL in there. How the hell did they get it crooked? Depending on how they installed it can be removed by backing it out with the HELICOIL removal tool or I have used a screwdriver to get them started and then wind them out of the block with a pair of vice grips. If the guy that drilled it sideways used JB weld on the HELICOIL you will have to drill it out, which isn't all that bad as you can drill it straight this time. That requires a hand drill and a plunging, leveling base. Something like this for $40 on-line. I would be tempted to make a base adapter to bolt to the head to assure it doesn't move but that may be overkill. You will use this tool in the future, very handy. Remember to measure the depth of the hole and set the drill guide so you don't drill too deep. If you have to drill it out and enlarge the hole to correct the issue, they do offer oversized HELICOILs. Before drilling it larger I would check to make sure there is enough meat in that area to allow for a slightly larger hole before drilling. A digital caliber is your friend. Remember to tape off the entire engine other than the hole itself where you be working, and vacuum/blow off the masking before unwrapping (there are things in there that don't like metals chips). Also, a good idea to make sure the hole is blind and not open on the bottom to prevent metal chips from entering the water jacket or crankcase. A little grease on the drill bit will help the chips stick to the bit during drilling. Use a vacuum and air to clean the hole out after drilling prior to unwrapping he block. There may be other methods and ideas, this is just how I would tackle it.
^ The threaded hole isn't parallel with the clamping surface of the head, the side load created when things are torqued down will put high stress on that area of the deck....where the crack is. The insert needs to be parallel...period.
Dang Bandit! You put some thought into this post! Very informative and understandable ! A like just wasn't enough for the amount of thought you put into it.
We used some threaded inserts for rotate bearing repair where Heli-coils wouldn't hold. Can't remember the name right now; but they were larger in diameter than hole for the Heli-coil. Thinking it may be possible to dig out the that crooked Heli-coil, drill and tap the hole for the larger insert square to the deck, and install the larger insert?
One brand is "Keen-serts", another is "Time-serts". I'd look into borrowing / renting a mag base drill to insure squareness of drilling / reaming etc.
I looked thru some old work notes with no luck as to manufacturer of those inserts. Being it's not a high stress area; you could have someone turn an internally and externally threaded bushing and use that for an insert. That way you could use regular sized drill and tap in the deck. Mag drill or that tool that bandit posted would keep you square to the deck.
May sound barbaric, but what I would do, is put the stud in the block where you want it and mark the position it needs to go to be straight. Then take it out and put two nuts on the block side of the stud as close to the bottom and top of the threads as possible. Put another nut on the head side , somewhat down low and mount in a vice and whack the nut with a hammer in the direction it has to go. The stud will bend. You don't need much, as its not terribly out of line. Reinstall in the block and see how it is. May have to do it more than once. Once you have it where you want it, I would then install the stud with green Locktite high strength/high heat bearing retaining compound. I'd be more worried how well the threads were tapped in the block for the insert, since they couldn't drill/tap it straight, how well did they tap it. Good luck Bill
There are two issues here, getting the oversize hole straight and just as importantly it has to be in the proper location. You might consider a sacrificial head that can serve as a drill jig. With an iron head bolted down on the block you gain a positive location, and I would surface the top of the head enough to use a magnetic drill. The mag drill can be rented and once you chuck up a drill that fits the hole in the head you have your location and can drill to the oversize you need. The big question is this- is there an oversize Heli-Coil or a Time-Sert that will work?
Bandit, Thank a million for your info, pic and wise advice. Getting together with a friend who has DCA Racefab here in town to plan our attack. Thanks to all else who contributed to this thread.
I'd go to my Engine Builder and borrow his Torque Plate and use it as my drill guide. Oh wait a second. I'd just have him do it for me to make sure there wasn't a second OOP's. There may not be a 3rd fix left in that block.
This is the sort of insert I was referring to: It has a "standard" outer thread, but in this case that is 9/16 NC, not exactly a common size tap. I believe they are sometimes made with a fine thread outside, which I would prefer.
I purchased an 8BA in parts and found the same as you at assembly, a helicoil that hadn't been installed correctly. I noticed it when trying to put the head on, I pulled the stud and cut a bolt so there was approx 1/2" above the deck surface, tried the head which went on ok. I then inserted the stud back in and dropped a washer over the stud , slid a tube over it and tweaked the stud so it was perpendicular to the block and the head slid on. I ran that engine for probably 60k miles and a couple of decokes. It's not how I like to build an engine but I was concerned I could have other problems trying to straighten a helicoil thread.
also keep in mind that the way the threads are rolled onto the studs, the end of the stud will cause it to 'lean' to one side when it is bottomed out in the hole. The thread insert has a tab in one end of it for installation...if the farthest most part of the threads come in contact with the tab on the stud, this could result in the stud really being kicked off to one side when bottomed out. The insert may actually be acceptable as is...I would try not bottoming the stud in the insert and see if it is still at a wonky angle...maybe you already have....if it is at a 90 degree angle to the deck this way then tighten it up like @krazee suggested, after the head is installed over the stud
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