2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Drill/Tap - Jb Weld?

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Old Dec 22, 2005 | 10:24 AM
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Wankel7's Avatar
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Cool Drill/Tap - Jb Weld?

Well, I screwed the pooch when I tapped my Greddy elbow for a new sensor. Ended up up cracking since I was trying to put a 3/8 npt sensor in that hole.

Anywho, I filled the hole and the area around the hole with Jb Weld.

My question is do you think I can redrill and then retap the hole thru the jbweld?

Or would I be better off just drilling / tapping thru the thinner casting near the hole?

James
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Old Dec 22, 2005 | 10:27 AM
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Remove all the JB-Weld, make a circular patch and have it properly welded in.

Then drill and tap in another location.

What tap were you using? NPT seals via the taper and the sealant that you apply. It doesn't need to be bottomed out.
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Old Dec 22, 2005 | 10:49 AM
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Originally Posted by Aaron Cake
Remove all the JB-Weld, make a circular patch and have it properly welded in.

Then drill and tap in another location.

What tap were you using? NPT seals via the taper and the sealant that you apply. It doesn't need to be bottomed out.
Yeah, I know...I pushed the NPT tap to far...leason learned.

Can you weld cast alum?

James
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Old Dec 22, 2005 | 11:30 AM
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Of course welding is best, but JB Weld will work as a second choice.

Redrill & tap the origonal hole.
If it starts to crack, JB weld the new sensor to the casting & patch the crack at the same time.
It may look crude, but it will work.
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Old Dec 22, 2005 | 11:48 AM
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Yeah, I was starting to think that JB weld the sensor in the hole....what are the odds of an intake sensor failing on a haltech setup....

Prob really high when I perma - mount it

James
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Old Dec 22, 2005 | 12:44 PM
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Got any spray silicone lube?
Lightly spray the sensor threads, then epoxy it in.
Then, if you have to later, you can back it out.
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Old Dec 22, 2005 | 01:08 PM
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Another thought: You can probably get an appropriately sized NPT bung and weld it over the hole. Gives you a much larger threaded area.

Yes, welding cast aluminium is easy for anyone experienced. Can be done using MIG, the appropriate wire and purge argon. If you find an old timer, they can do it with a torch, aluminium rod and the correct flux. Or anyone with a TIG...

I assume you are referring to the air temp sensor? They're a standard GM part, so they're as reliable as any other GM (draw your own conclusions). But I still would not JB-Weld it in.
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Old Dec 22, 2005 | 01:09 PM
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yes you can weld cast aluminum, just need to make sure it is clean with hot water and soap and rinsed. i would weld it. but you can getto it with epoxy. either way you will need to clean it really good for it to work best
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Old Dec 22, 2005 | 01:13 PM
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Another option is to braze. Rods are available at most plumbing stores and can be done with a propane torch run on MAPP gas (brazing fuel).
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Old Jan 13, 2006 | 08:02 PM
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Well, I drilled thru the thin metal above the normal place for the temp sensor. I motivated my NPT tap into that hole. It only cut 2 threads.

But I put the sensor in there with teflon tape and pressurized the intake system to about 30psi. Not a single leak. And the JB weld sealed up the crack and bung nicely.

Problem fixed

James
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