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364" intake thread repair


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20210329_110553.thumb.jpg.5c8102bb59af667f303a39efe95c9c24.jpgThis is the repair bushing I fabbed to repair a previous owners attempt at drilling out a broken stud. Instead of drilling on center there was an attempt to drill small holes each side of stud making it impossible to simply use a thread repair kit. I drilled the 5/16" hole in the shank of a 1/2" fine thread bolt then after drilling and tapping damaged hole to 1/2" NF, I cut the " bushing" off the end of the bolt to use as a repair for the damage that went out that far fro crazy, hack attempt! I want to lock this into place permanently, but Red Loktite is disabled by heat. So any chemical engineers or savy experienced mechanics, etc. Please weigh in! Id like to hear some ideas, past experiences with this, whatever. PITA FOR SURE! Thanx in advance!

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Good job.   Always rewarding fixing others screw-ups. 

Use a small punch and stake it in place. 

I often need to replace/repair #8-32 screws in aluminum Reatta headlight motors.  The screws used are thread forming and

a little salt water from winter roads will lock the screws in place.   Owners that try to fix their headlight motors twist off the screws 

hex head then try and drill them out.  They do not realize the thread forming screws are heat treated and a normal drill will not

drill them out.  They end up drilling a hole beside the screw.   I found threaded brass inserts that can be pressed into the hole and

that saves the headlight casting.  

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@2carb40,  If that location is not in an exhaust crossover point then any high temp loktite will most likely work just fine. The high temp products are rated for applications up to 450 F.   A normal intake should not get that hot. In any case, even if it did release it would still be very sticky and be unlikely to actually loosen.  Other options would be to stake the side with a punch point, use a HIGH temp epoxy or last case, drill and pin the thread edge with a pin or thread the pin hole and use a set screw.  I would just use red loktite and install the carb 😀.

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Thanx much for the good info! I thought red locktite would suffice, but I think using gaskets that cutoff the carb heat passage would also be reassuring and carb heat uneeded in most collector car use. I thought about tapping a small set screw in the mating area of the "bushing"  and the cast iron surrounding it cuz they screwed the hole up to the point where even drilling out to 1/2" there is a slight partial curved slot left that is questionable, which would be a natural spot for the lock of a small set screw suggested and red locktite.

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Silver solder will hold it in place .

Unless your threads are very lose high temp loctite should work just fine as it is staying in place and not a moving part.

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Thanx for the reminder! I didnt remember about silver solder. Still some left from Dads stuff. Saved us when fixing a leak when sweat soldering didnt "take".

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There are also much stronger loctite products made to fix bearings in housings, etc. It would never come out. But I am not sure it would be appropriate unless you can be sure you can easily get the bushing in place before the product starts gripping or you would end up with the bushing half in and half out.

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Posted (edited)
1 hour ago, 56 Buick said:

There are also much stronger loctite products made to fix bearings in housings, etc. It would never come out. But I am not sure it would be appropriate unless you can be sure you can easily get the bushing in place before the product starts gripping or you would end up with the bushing half in and half out.

The strategy I used when I converted a 1952 four barrel intake for a 320" straight 8. I had to fabb similar bushings in order to use the two barrel exhaust to overcome the unobtainium of the 4 barrel only exhaust center section. Threading a stud into the bushing then a nut onto the stud I used the nut to "lock" against the bushing by putting two nuts at the top end of the stud locked together. It allowed me to install the bushing flush with the intake  and still loosen the jamm nut after the red locktite cured and the stud then turned out with the 2 locked nuts at the top. The process of "jamming" two hex nuts together solves issues in a number of different tasks when other options arent available. Takes some malice of forethought.

Edited by 2carb40 (see edit history)
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