Need thread pitch / spec / dimensions...

[Schrade]

The speed shop called today; they need "thread pitch" for the Air Inlet fitting (to the exhaust manifold???).

I'm not 100% sure of the hardware configuration, since they've had the car for most of the year that I owned it - I know only what he described. I told him I'd go through the FSM to see what I could find.

Anyone already familiar with what they're describing, that they need?

[Blue Flame Restorations]

Contact Jerry's Gaskets. Jerry will know.

[Schrade]

Will do Brett; thanks there...

[Jagdpanzer]

Please point it out:

http://jerrysgaskets.com/store2/root..._image&pID=378

[Schrade]

I'm presuming here, jagdpanzer, that he needs the thread pitch of the encircled fittings:



Why, I don't know, but I'm off to get up there in the AM here.

Where's Jerry here? Know the thread dimensions???

[mike100]

I think it is 3/4" and the thread pitch is 14NC. I just repaired an air tube fitting and i got a bushing with the same external thread.

Interesting to note that many of the small block applications one-way air injection check valves are one size smaller.
The 63-504 fit on my repair: http://www.downwindmarine.com/Pipe-R...-90891187.html (note dimensions are for inside diameter and threads- the outside is 3/4's)

[Schrade]

Originally Posted by mike100

I think it is 3/4" and the thread pitch is 14NC. I just repaired an air tube fitting and i got a bushing with the same external thread.

Interesting to note that many of the small block applications one-way air injection check valves are one size smaller.
The 63-504 fit on my repair: http://www.downwindmarine.com/Pipe-R...-90891187.html

Thanks there Sir..................................

[WVZR-1]

Originally Posted by Schrade

I'm presuming here, jagdpanzer, that he needs the thread pitch of the encircled fittings:



Why, I don't know, but I'm off to get up there in the AM here.

Where's Jerry here? Know the thread dimensions???

In that image the threads are 1/2" - NPT which when measured externally is a dimension something near .830 or so. !/2" NPT is 14 TPI as is 3/4 NPT but 3/4NPT is a dimension greater than 1" when measured externally. NPT is based on the internal diameter of the pipe. The bushings that "mike100" references to are NPT also and the reference to a 14NC is not correct, it's 14 but it's NPT. The image is that of a later manifold but I believe the AIR check valves are the same all years.

1/2" NPT 14 TPI

[Jagdpanzer]

I have to agree with Dave, 1/2" npt tapered pipe thread
When I get home this evening I will dig out one of my old exhaust manifolds and confirm.

[mike100]

yeah, I guess the 1/2" refers to the ID of the bushing...I just recall finding some parts in the plumbing section of a good hardware store here. I was going to hack off some fitting from the junkyard, but the LT5 air injection is double tubed and uses much larger check valves (thread-wise) than most of the small block cars.

At any rate, the link above for the part I mentioned is the correct thread.