Jump to content

Just bought a 521


Recommended Posts

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.

Link to comment
  • Replies 2.1k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

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.

  • Like 1
Link to comment

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....

  • Like 1
Link to comment

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.

  • Like 1
Link to comment

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.

  • Like 1
Link to comment

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





  • Like 1
Link to comment

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.

  • Like 1
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.