The Stovebolt Site Forums The Shop Area Engine Shop Stripped intake threads.

Well, I contend the treads were crap to begin with, nonetheless I stripped one putting the carb back on. Is a helicoil type repair the best?

Or drill and tap to the next larger size bolt and if it doesn't fit, make a stud with both threads on each end.

Ed

What year, what vehicle, what threads? Is this a stud or female threads? Aluminum or cast steel?

Female threads. 63 c10. 230.

Did you already run a tap in there to see if you can restore threads? What size and pitch is the thread?

No. It happened late last night and i didn't have the tools. Plan to take the bolt to autozone and figure it out tonight.

Doesn't the manifold have two studs? What did you strip?????????? Did the studs unscrew and you used them as bolts and stripped the manifold or did you use bolts because studs were gone?

Anyway, you have to take the manifold off to work on it. A machine shop or drill press will be your best bet unless someone here has one. you can as said, tap to next size. They sell stepped studs; or drill out the carb hole. Inserts are too much work and money when you can just drill and tap. They are mostly for aluminum.

In general Heli-Coil is the best idea for thread repair/replacement in a threaded hole, gets you back to standard size and the hole is now stronger than it ever was.
Some odd situations will benefit from a different repair, but if a Heli-Coil will work consider that first.

It looks like its been jimmy rigged. One side has a stud with a nut to attach the carb. The other has a threaded hole and a bolt. You think I need to take it off? I can't repair with it on the truck?

I’ve repaired a whole bunch of messed up bolt and screw holes. I disagree with most of the above quote.

I would repair it on the truck, a carb bolt hole in the intake is very easy to get to.
Drilling, tapping and installing a Heli-Coil is easy enough if you can work carefully and a small kit with tap, drill, and installing tool won’t cost that much and you can use it again many times, when necessary replacement inserts are cheap.

I would take it off and I'm pretty good with tools and very mechanical. Have done a lot of work like that also. It's just I've learned when you only have one manifold, that's what you do. If you think you can hold a drill straight as a drill press, tap straight while leaning over, not drop anything down the hole.......do what Grigg says. Trying to advise with safety/risk vs reward in mind. (extra time to take off manifold vs better positioning of part, your body, tools. Thus avoiding a major malfunction). Considering an unknown experience level. Could be the wrong approach sometimes.

I've repaired quite a few stripped threads with helicoils, and I wouldn't hesitate to do it with it installed. Stuff a rag in the intake to keep stuff from falling into it and do the deed. I've even omitted the drilling and just used the helicoil tap when the threads were completely stripped away. It's not all that hard to run the tap in straight, as there's a pilot hole already there. And cast iron isn't that hard to tap, nearly as easy as aluminum.
I agree with bartamos though in that taking the manifold off would be the best (and safest) way to do it. It's not that much trouble to take it off, but it's not absolutely necessary.

Removing the intake and exhaust manifold if not already necessary is asking for more work and possible troubles.
Even with the manifolds off and at the drill press it’s not an easy job to block, clamp, shim, adjust, and check before drilling. The manifolds aren’t flat on the bottom.

There are drill and tap guides available, or make your own temporary ones with a block of wood and a drill press.
https://www.shop.biggatortools.com/main.sc
With those to help drill and tap a somewhat less skilled person might get perfect results. In any case experience leads to skill, neither comes without trying new things.

Without those guides go slow and check drill and also tap for square at two points 90* apart with a small square, even a business card is a handy square.

Commentary not aimed at anyone;
One other thing, Don't strip threads. There is no excuse. When restoring, refurbishing or just repairing, you must inspect, size, clean and chase all internal and external threads. This is a big part of the work that needs to be done. I do it all the time. I have taps already loaded with 1/4-20, 5/16-18, 3/8-16. I either sandblast original hardware or wire wheel it clean and new and then chase if it won't past a test. Wire wheel is preferred. I have no fingerprints left. Everything goes together nicely with no hang ups. This part of mechanic work is often over looked....and again, for the beginner, don't strip threads. STOP if threads don't feel easy to tighten. Always thread hardware on by hand until well engaged. Never start a bolt or nut with a tool.
New hardware must be tested. Sometimes the tolerance/quality on the plating of Chinese hardware will not thread easily into original SAE threads. I have had to chase new hardware many times. That's why I save, tag and reuse 95% of the old hardware.

Note 1: You must be extremely careful when chasing captive/captive floating/no access hardware. Use liquid wrench, oil, etc. and slowly turn tap or die 1/2 turn and back off, then 1/2 more and etc. Be SURE you know the size and pitch. Obviously, if you break it loose from the weld or cage, you are the one who is screwed. Starting and using a tap or die, to chase threads, also needs special care. Don't strip threads that way either.

Note 2: Some of you guys tend to forget, everything is simple if you are already good at it. A novice or trainee needs to have the best chance for success. Then when they get "good at it" they can develop quicker methods. If they ever even do it again. Not speaking about Matttttttttt's abilities, just a general comment. If a person asks this kind of question, they could be a novice. Grigg is a Machinist/Fabricator, Kevin and I are Mechanical Engineers. We all love to work on old trucks and drive them. We need to help others and learn from others. We need to keep in mind not all are as experienced as we may be. I realize there are several different ways to accomplish a task. I learn on here everyday. I just give my opinion. The best way to get answers is to get various opinions, so a person can decide what is the best approach to do something. We are very good at that on Stovebolt and have done that for this member. Well done. I learn more by helping than the poster does.

We all get that, but we have no control over what someone else has done previously (remember these trucks are senior citizens and have likely been worked on by some hack a number of times). I've run across a number of threaded holes that are on a razor edge of being stripped already, and strip on the first turn of the wrench. At that point you need to break out the helicoil kit.

Excellent comments concerning chasing threads. If you reinstall a rusty, cruddy bolt in a rusty, cruddy hole, it's going to take some of the threads out. If you can't run them all the way in with your fingers, you either haven't cleaned them or you've cross-threaded them. Cross threading is a problem if someone else has already done that. Bolts have to be started STRAIGHT.

Thread chsing is not thread cutting. A tap or die will chase if need be. It will also cut all the threads off if you let it. I use a cut off wheel to make any bolt a thread chase type tool. That and a bit of grease will prvent chips from getting into the intake. Just watched a nice youtube video. A guy put a bolt and 2 nuts togethe. Drilled the junction on a drill press. Removed the nuts and has a tap like thread chser bolt and 2 thread chaser nuts(die) That is about as cheap and easy as can be. If the hole is in fact stripped. Then an insert is the way to fix it. Step type studs can be difficult to find and cost some too. The problem is different if you are fixing a side mounted intake(inline six) or a top mounted intake Most V-8. But if the issue is with the top mounted carb, then that is the same. One will need to drill or chase into Iron(the head) the other will need to drill/chse into aluminum(after market intake) or iron(Stock). It is different working on those 2 materials. Iron is easy to tap/ chase. Aluminum is a lot softer. Keep it straight and go slow.

Thread "chasers" are snake oil. They are just screw threads with a big cleanout groove. Like when you make one from a bolt. I use taps and dies to cut thru rust and corrosion. It taps the same thread as the original tap that was used. If you can't do it, use a "chaser". They get stuck on crusty threads just the same as a bolt would. I'm not trying to clean off grease, I do that first with gas, blaster, WD40, carb cleaner, soap or wire wheel. A chaser is BS. A fake tool. Machinists I know use a tap and die to renew threads. I'm not talking about fixing stripped threads. I'm talking about restoration of an old truck. Mostly threads I cant sandblast or wire wheel.

Matt,

This type of product is way better than a helicoil:

http://www.repairengineering.com/keensert.html

I have used them to repair damaged threads in motorcycle engine castings, including spark plug threads. They do not unscrew like helicoils because they are locked in place by 4 keys. Other companies make very similar products. You are close to Industrial Pipe and Steel in South El Monte and they probably have a selection of inserts.

If you have access to a lathe it would be simple to make a stepped stud allowing you to simply use the next larger threads in the manifold and leave the carburetor flange unmolested..

Drilling the carburetor flange to a larger size seems like a really Mickey Mouse "repair". I sure wouldn't do it

Enlarging the carb clearance hole is down on the list. In case a person runs into trouble. We are only talking .031 or less, larger on the radius. It's in the "Goofy" range but not Mickey Mouse.

Mickey Mouse is JB Weld. I got that in my back pocket.

Everything prior to this post was all, blah, blah, blah, blah fricking blah to me. Now, finally, someone starts talking my lingo!
Thank you bartamos!

Edit: There was plenty of good info provided in this thread. Just sayin'.
Carl

When a tap or die gets dull enough to stop cutting clean threads in a previously unthreaded application, rather than discard it, I set it up in a lathe and use a tool post grinder to take a few thousandths off the top of the thread- - - -internal or external. Now I've got a chaser that isn't going to create an over or undersize when I use it to clean up a dirty or damaged thread. I also give those modified taps and dies a dunk in my gun-bluing tank. That way I can't mistake a chaser for a threading tool, tap or die. The black ones are the chasers!
Jerry

.. just separate the tares from the wheat. Use what we can that helps "ME".

....I enjoyed reading them all. In real life I have used just about every one of them except the kennsert!!!!

I wouldn't say way better, although I have never used one. I have read the install instructions though and they seem harder to install than a helicoil, and they were more expensive as well. I have never had a helicoil back out on me. Once they're in, they're in as the coil is oversized and the install tool pulls them in place.
If I had a really tough repair, like an SAE boss o-ring fitting, I might consider a solid insert like the keensert. A helicoil wouldn't be appropriate as the top of the threaded hole needs a taper to contain the o-ring and seal it. But there aren't any SAE boss o-ring connections on my Stovebolt, so I'll stick to helicoils.

Just like using an 8-lb. sledgehammer to swat flies! Overkill!
Jerry

Jerry.........A gun bluing tank? Is there anything you don't have?

I would love to see your wish list.
1. Cryogenic chamber
2. WASP BigDelta 3D printer
3. Home surgical room
4. 6 Axis mill
5. Harley (sell the rice burner)
6. Heliport
7. Paint booth with programmable robotic spray guns
8. Submarine
9. Drive-in theater
10. 40 Willys coupe
11. MAGA hat

Actually, I've been riding a Harley Soft Tail for about 6 months. It's my parade bike for Patriot Guard funeral escort missions. The Gold Wing is for road trips. I had three 6" X 6" X 36" stainless steel tanks built for a hot-water bluing system about 30 years ago.

Welp, I helicoil'd it and it worked like a champ. First time doing it on a car. Did plenty in my ski shop days. As I was putting it all back the fuel like flange looked worn sure enough it leaks... Next weeks project and next post. Thanks for the input.