SBC intake manifold studs

[sweetnomad]

Got a situation on an aluminum manifold where someone has replaced one of the four 5/16"studs where the carburetor bolts on with a 3/8" stud. I've been looking on line tonight for a step down stud from 3/8 to 5/16. I saw a few but they weren't long enough on the 5/16 side to go through the carb flange. I'm guessing somewhere down the line on this early Torker, this particular hole was stripped out and that's how they decided to fix it. I don't really want to drill my flange on the carb.

 

[Kurtm333]

Thread repair

Just pull the stud and put a thread saver in it. I can get them from my local AceHardware. Use the kind that fits in normal threads and uses a flat head to screw in and loctight to keep it there. Easy fix

Kurt

 

[sweetnomad]

Kurt,I'm not sure if I made it clear or if I don't understand. They already drilled it out for a 3/8 stud,got to figure out how to get it back down to 5/16. Are you speaking of heli-coil ? Let me know

 

[Old Iron]

Use a 5/16 helicoil the tap is larger than a 3/8 bolt so, when you use a 5/16 helicoil tap it will take care of your problem.

 

[sneakysnake]

Kurt,I'm not sure if I made it clear or if I don't understand. They already drilled it out for a 3/8 stud,got to figure out how to get it back down to 5/16. Are you speaking of heli-coil ? Let me know

This is what he is talking about but most are 1/4 to 3/8 not sure of a 5/16 to 3/8

 

[sweetnomad]

Old Iron as I'm sure you know it's a blind hole. I put in the heli-coil in after using the provided tap,afraid to drill it anymore for I might go through the runner. I couldn't get all of the insert down in there had to cut off two rounds. It should hold, it's in the depth of the hole at least the diameter of the 5/16 bolt possibly a little more. The other three are a little loose,going to use loctite thread maker. I've used it a long time ago and of all things on a cylinder head exhaust bolt and it worked. Thanks for all of you guys and your input !!

 

[Kurtm333]

Sory Late to the party... The pictured one was what I was thinking of, glad the helicoil worked though.

Kurt

 

[sweetnomad]

No problem,I vaguely remember those thread savers,been years since I 've seen one. Matter of fact it was back at a VW dealership in the late 70's. We've got a really good h/ware store here that has about every darn thing in it under the sun,got to go see if he's got some of these. Does it have to have a special tap to be able to thread it in ? Looking at it ,can that shoulder on the top be ground off after it's installed,because it has to be flush if I would have used it in this instance ?

 

[Old Iron]

Yeah I'm with ya on the blind hole.
You done what I do and get all the coil in you can and then cut the top off.
I've done several and it has worked every time.
Glad I could help

 

[sorj]

another trick would be to weld a 3/8 set screw to a 5/16 stud. Its not practical but is another way to acomplish you goal. Being your not holding a bunch of pressure, you probably can braze it. I've had to do this trick on some of the specialized equipment when inserts cant be found on the side of the road and all you have is a shop truck with welder and various hardware...