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Just bought a 521


mainer311

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Man it just snowballs with these trucks lol. Welcome to the club. 1/4” BPST? I say that cause I just plugged my intake manifold with one. maybe easier to just retap?

 

How hard was it get those EGR bolts out? Mine are frozen along my down pipe flange so I can’t even take my exhaust manifold out of the truck.

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The upper EGR bolts came right out. The studs on the other hand... I got one out so far. It took a lot of heat. I’m saving the other two for tomorrow.

 

Get it orange around the base of the stud(don't heat the stud), then hit the side of the manifold near the stud with a hammer, then turn the stud out with vice grips.

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Yeah, that’s what I did. A propane torch only gets you so far though. One of them successfully came out, just took some time.

 

Hoping I can find the thread size on the manifold plugs today.

There is a good chance they are bspt threads... since you have the manifold off easiest thing to do is retap the bspt with an npt tap... npt plugs are alot easier to find locally....

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They aren’t tapered. If you look at my picture, the compression happens at the flare on the end, like a brake fitting. There’s a second tube protruding through the manifold that has the female flare on it.

Best I can tell, it’s an M14 fine thread. It VERY closely matches a 1/4 NPT, but the threads don’t line up. I’m going to see if I can get a measurement on the threads and then order some short bolts with copper washers.

 

EDIT: Just did the conversion. 1/4 NPT is 18 TPI, which works out to a metric pitch of roughly 1.4. .1mm is practically nothing, so I'm assuming the thread is an M14 x 1.5. This would account for the threads being slightly different.

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I just checked with the Datsun Roadster guys. It's an M14x1.5. I can assure you, there's no taper. You don't want the threads to lock up before the flare gets compressed.

 

With that said, since the tubes are removed, jamming a 1/4 NPT plug in there would probably work, but I heard the fit isn't very tight.

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here is what i did to my manifolds, sorry for the pictures i just took them. i can't remember the thread size

 

https://s1.postimg.org/2vqunbf60v/exhaust_manifold_plug_1.jpg

 

https://s1.postimg.org/8b24jwzbnz/intake_manifold_plugs_1.jpg

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Nope. It’s M14x1.5. You could chase the threads if you wanted to, but mine were very clean to begin with.

 

I know the paint won’t last, but it’ll look okay for a little while.

When using heat paint, it helps to heat the metal you're painting before the paint goes on. Not red-hot, but hot to the touch. It burns the paint on giving it a head start and will last longer this way.

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