Stripped threads in valuable intake- Time Sert vs. TIG and redrill or other

[Tim Ayers]

Hi All:

The threads on the carb and fuel pump bosses on my Weiand high rise intake are almost stripped. Some thread is left, but they are weak.

I'm going back and forth on how best to fix them.

Here are some of the ways I'm thinking of doing it:

1) TIG the holes and retap
2) Use Time-Sert inserts (fuel pump stand holes are close to the edge. Should I be concerned about Time-Sert cracking the surrounding material? I've never used them.
3) Locktite makes a thread repair product. This seems to be the easiest and cheapest. Not sure if it's any good and I am concerned it will contaminate the holes if I do decide to TIG them.

Thoughts?

[FRANK PKNY]

be careful and use the inserts they work very well just don't overtighten them. if all fails you can still weld and re-tap but that's
a very risky and one must be very skilled to do.

[1948F-1Pickup]

I probably wouldn't use the Loctite product.
You didn't post a photo but I think your heliarc concept might be best.
I'm assuming you're not doing the welding. This is not something you want
to do yourself unless you're experienced in this type of repair..... the "learning
curve" is quite steep and probably fairly unforgiving.

And after your repair, I don't know if it's appropriate for what you're doing but studs,
rather than mounting bolts, are far more durable.

[Tim Ayers]

Originally Posted by 1948F-1Pickup

I probably wouldn't use the Loctite product.
You didn't post a photo but I think your heliarc concept might be best.
I'm assuming you're not doing the welding. This is not something you want
to do yourself unless you're experienced in this type of repair..... the "learning
curve" is quite steep and probably fairly unforgiving.

No. I would take it to an experienced shop who specialize in TIG. I am concerned that the aluminum is of pretty poor quality like most old intake are.

[Ronnieroadster]

Tim on intakes I have restored with similar issues I would first Tig weld the holes next step would be a slight resurfacing to make sure everything was flat and then tap the holes to the correct 5/16 coarse thread. Another way I have accomplished a repair without welding was with a step stud it is a bit more involved. The stud has a 3/8 coarse thread on one end and has a 5/16 thread on the other end. I make the step stud from a 3/8 bolt with a long shank that I then turn the shank to the 5/16 diameter so I can now thread it to the fine thread for the nut. Step studs I believe are available ready to use I just make them when needed so never took the time to source them. Using the step stud usually is the least amount of damage to a delicate and rare intake.
Ronnieroadster

[Tim Ayers]

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Originally Posted by Ronnieroadster

Tim on intakes I have restored with similar issues I would first Tig weld the holes next step would be a slight resurfacing to make sure everything was flat and then tap the holes to the correct 5/16 coarse thread. Another way I have accomplished a repair without welding was with a step stud it is a bit more involved. The stud has a 3/8 coarse thread on one end and has a 5/16 thread on the other end. I make the step stud from a 3/8 bolt with a long shank that I then turn the shank to the 5/16 diameter so I can now thread it to the fine thread for the nut. Step studs I believe are available ready to use I just make them when needed so never took the time to source them. Using the step stud usually is the least amount of damage to a delicate and rare intake.
Ronnieroadster

Interesting. Never heard of a step-stud and we learn someone new each day. Makes sense. Thanks, Ron.

[Krylon32]

I found step studs on a site called Allen's Fasteners

[Tim Ayers]

Originally Posted by Krylon32

I found step studs on a site called Allen's Fasteners

Thanks. Forgot about Allen's.

Allen's is also the best place to purchase ARP products as well.

[Mart]

If the holes have plenty of solid metal beyond the end of the thread you could drill deeper and tap the holes deeper. Then put the studs in, making sure the UNC end is long enough to get well into the new threads. And then make sure you are respectful of the threads and don't overtighten the nuts.
Why not even mention helicoil? They need less material to be removed than timeserts or other inserts. The helicoiled thread is stronger than a non helicoiled thread.

All these holes take studs. Once fitted they should never have to come out. It makes you wonder how they came to be stripped.

Mart.

[Tim Ayers]

Originally Posted by Mart

If the holes have plenty of solid metal beyond the end of the thread you could drill deeper and tap the holes deeper. Then put the studs in, making sure the UNC end is long enough to get well into the new threads. And then make sure you are respectful of the threads and don't overtighten the nuts.
Why not even mention helicoil? They need less material to be removed than timeserts or other inserts. The helicoiled thread is stronger than a non helicoiled thread.

All these holes take studs. Once fitted they should never have to come out. It makes you wonder how they came to be stripped.

Mart.

Hi Mart,

Not sure how they became stripped. It was that way when I got it. I didn't mention heli-coil for other praise time-serts so highly.

Heli-coil is certainly another option.

Allen's fasteners has ARP step studs fairly reasonably priced.

[tubman]

I'll take the contrarian view again. In 1987, when I bought my '67 corvette L79, it had stripped threads in the intake where the thermostat housing mounts. Being short on equipment and experience back then, I used the "Loc-Tite" thread repair product mentioned above. It obviously worked, and I forgot about it. and used the car almost daily in the summer for 30 years. A couple of years ago, I had the opportunity to replace the valve seals, which required disassembling the top of the engine. While removing the thermostat housing, I suddenly remembered those long ago repairs. On assembly, I took a good look at the threads in the manifold and re-assembled it as is. (I did replace the thermostat and gasket, though). It didn't leak this time either.

It obviously worked satisfactorily, and after my experience, would suggest it for repair of the type of problem you have. It has the advantage of not affecting the original part, unlike the other methods. You can always step up to one of them if it doesn't work. My experience discourages me from any kind of welding on old aluminum castings, and there is the problem of thin margins with any type of threaded inserts.

There is really no ideal solution for all situations, but I think it would be a mistake to reject the "Loc-Tite" solution out of hand, especially if there are some threads left.

[KiWinUS]

Tim always consider what you are repairing. In you case a rare intake. You do not want repair to be visible. That rules out welding unless it’s a last resort. I personally am not a an epoxy guy. Band aid to me. Just my personal thought process as engines are not something I don’t gamble with. First for me is helicoil. If that won’t work then I would “keensert” “timesert”. Or as RR suggested step stud. Last for me is weld. I look at it as a process. If the first “ best choice “ fails use second option. I have used all methods suggested & above is how I would proceed with any antique speed equipment. Cheers
Tony

[tubman]

Did you know that some current vehicles have more steel panels attached with epoxy than welded? The advances in chemistry in this area are staggering. It's OK to not be an "epoxy guy", but if you are, you are missing out on a lot. If it was that good in 1987, can you imaging what it's like now?

It has always been my policy to try the "non-destructive" method first (unless it is obviously not practical, which seems not to be the case here).

[KiWinUS]

Tub. Yes we/I use many epoxy/ composite products & yes they are amazing. Different strengths, cure times chemical resistance the features go on & on. For this application just not “MY” choice.
Cheers
Tony

[fordor41]

If you use a "key lock" type insert insert, they usually have thin wall and thick wall if you're worried about too large. I've used dozens of them and never had one pull out. Check McMaster-Carr supply

[Karl Wolf]

To my way of thinking, Helicoil is the way to go.
I would make a guide of wood, drilled in a drill press, to make sure the tap is vertical to the surface,
Karl

[95476]

I recently had a cast aluminum piece that I needed to repair. The oil in it made TIG welding difficult. The guys at the welding shop suggested trying some of that low temp aluminum brazing rod, similar to Muggy Weld. It tried it and it worked perfect. After I was done drilling and tapping you could not tell there was a repair.I was surprised but will use it again.
You can use a propane torch to heat the parent metal if you don't have oxy/acetetelyne.

[flatmotor40]

I use a small block of aluminum tap the the correct thread size to keep my tap straight and square.Have all threads sizes in block to use.I also use a lot of helicoil and thread inserts.Wouking on 35Chevy and use all threaded inserts on all screws and door hinges.Bought the tool on Amazon but other people have them now

[flatmotor40]

But the nutserts I was taking about will only be used for like sheet metal stuff not solid surfaces.Buy most of my stuff from Bolt Depot

[JWL]

I use 3/8 X 24 to make inserts of extended length for gripping to install. Must be well centered in the lathe before drilling and tapping for the 5/16 internal threads of the fuelpump stand. Screw insert with a dab of locktite and let set for a day before cutting off the extra length and establishing flat surface with the intake manifold.