Odds Of Successfully Welding A Cracked Intake?

So I apparently overtightened the 90 degree fitting for the heater hose on my Offy 4bbl intake resulting in a hairline crack. I discovered this after filling the coolant system and running it. I tried to patch it with JBWeld, which didn't work likely because it was wet from coolant when I smeared it on there. My plan is to pull the manifold again and grind off the JBWeld, but my question is whether to try the JBWeld again after thoroughly cleaning the area around the crack or take it to a shop and have it welded up. The crack runs vertically up the port about 1/2" to the top. I haven't used JBWeld much and am wondering if that would be sufficient or should I just get it welded. Also, if I get it welded how likely is that going to fix it? I'm hoping my manifold isn't just garbage at this point...

 

take it to shop, fix it properly if thats an option. jb weld is intended for emergency use as a bandaid until the problem can be fixed properly. say, if it cracked on a trail, use it to fix the crack to get you home and then have it fixed.

-just my 2 cents.

 

Copy. I just wanted to make sure welding it up is a viable solution first. I've got a guy locally who should be able to do it.

 

Yep should be able to tig that up.
JB weld will seal up a diff cover with a thumb size hole. Well enough to keep wheeling...

 

Thanks for the vote of confidence! I just dropped it off for welding.

 

Take the intake to a good welding shop that specializes in welding aluminum. They wil have to make a cut enlarging the crack, and weld from there.
I avoid using teflon thread tape on pipe threads, especially in aluminum. I typically use pipe dope or Permatex Aviation.
-Donny

 

My options locally are limited, but the shop I dropped it off at came recommended so hopefully it works out. I've been using the Permatex liquid teflon stuff.

 

Though I've never used this Permatex product, I would shy away from anything "teflon". This material is great for steel pipe fitting where the sharp threads mash into each other as the taper is pulled tighter, with the aid of teflon.
Those same threads act as a wedge, and especially in a casting like your intake, the teflon makes it so easy to thighten too much. Save the teflon products for heavy items that have little to no chance of splitting.
I learned about this years ago when I was plumbing the air system in my garage. I used 3/4" and 1/2" galvanized pipe. I split a steel coupling when tightening with teflon thread tape.
-Donny

 

Permatx Never seize is also a good option considering the 2 dissimilar metals. Always be cautions with soft metals like aluminum no need to over tighten your always want some threads showing.

 

I agree on the permatex and welded solution. No teflon. Go easy on the wrench.

 

I feel really bad about cracking the manifold like I did. I was literally just lining up the 90 degree tubing so that it pointed at the heater when it split. I'm hopeful that it gets welded up and is good as new again.

What are you guys using to seal up the manifold? I've read that a blob of RTV at each corner of the rubber seal is sufficient. Do you also put RTV around the coolant ports? What about the thermostat housing - gasket plus RTV? Just gasket? Just RTV?

 

Don't use the rubber end seals with an aluminum manifold. Lay a thick bead of RTV across the top of the block.

 

Not to mention that Teflon turns out to be pretty nasty for humans and the environment:

 

It's Permatex thread sealer that I have, I just call it liquid teflon. I have no idea what's in it. The good news is I got my intake welded up and the heater hose fitting reinstalled, and no leaks!

 

Hey, great news!