Need intake coolant fitting

[kawahonda]

I'm having a hard time finding a straight heater hose coolant fitting for my LD340. It does not use 1/2" NPT, but rather what seems 5/8" NPT.

Please don't tag anyone. I've already "tried" one venue.

[Bullitt-]

    doesn't give thread size...

https://www.manciniracing.com/hehonib.html

[Burdar]

Have you tried the HELP line of parts at your local parts store?

[kawahonda]

I haven't gone into part stores yet but I've been searching the web quite a bit!

[DeathProofCuda]

   doesn't give thread size...

https://www.manciniracing.com/hehonib.html

The big block fitting sets shown in the Mancini link look like they include a 5/8" threaded fitting.  I think I have a spare one in the garage somewhere that I can check.

[gzig5]

The OEM fitting heater hose fitting I bought was one size too small for the LD4B intake so I just picked up a brass reducing bushing at the hardware store and got on with life.

[kawahonda]

Yea. It will all get sprayed orange anyways. Sounds like I may need a reducer.

I'm pretty sure there has to be a 5/8" NPT 1/2" Hose barb slotted fitting out there. I think just jollying around to part stores is going to create a lot of time burn.

[Brads70]

No such thing (that I know of?)  as a 5/8 NPT thread.  likely 3/8 OR 1/2 NPT
5/8" is referring to the heater hose size

[kawahonda]

The LD340 does not have a 1/2 NPT header hose connection. A 1/2 NPT falls through the hole.....

Whatever the "long" one in this kit is (I believe 1/2" NPT) falls in the hole:

https://www.manciniracing.com/19ahehonikit.html

But I do agree that there appears to be "no such thing" based on how much I've looked!

[DeathProofCuda]

What is the diameter at the face of the threads for the fitting that will fall through the hole?

What is the internal diameter of the hole?

A 1/2" NPT fitting is right about 3/4" at the face of the threads.  Overall diameter is listed as 0.840"

[Brads70]

The LD340 does not have a 1/2 NPT header hose connection. A 1/2 NPT falls through the hole.....

Whatever the "long" one in this kit is (I believe 1/2" NPT) falls in the hole:

https://www.manciniracing.com/19ahehonikit.html

But I do agree that there appears to be "no such thing" based on how much I've looked!

Tap drill size
for 3/8 NPT is 9/16 or .562 
for 1/2" NPT is 45/64 or .703"
for 3/4 NPT is  29/32 or .906

Are you sure 1/2 NPT falls in? 

[kawahonda]

I can't find the fitting (It will pop up I'm sure), but the intake fitting bore measures .588"

I have a freeze plug fitting that threads perfectly in it, and it measures. .666"

[Brads70]

I can't find the fitting (It will pop up I'm sure), but the intake fitting bore measures .588"

I have a freeze plug fitting that threads perfectly in it, and it measures. .666"

So if I'm understanding this right , its 3/8 NPT . It's a tapered pipe tap so it gets bigger at the opening of the hole , as you tap the tap drill sized hole the tap cuts on a tapper making the opening bigger than the tap drill size.

[DeathProofCuda]

 

Here is a photo of a big block set. 

The smaller one shown at the top is 1/4" NPT.  It is shown next to a 1/4" NPT air fitting.  Outside thread diameter is 0.54"

The larger one is 3/8" NPT.  It is shown next to a 3/8" NPT tap.  Outside thread diameter measures 0.66" with my caliper.

The large tap at the bottom is 1/2" NPT.  Outside thread diameter is 0.84"

[kawahonda]

This is awesome.

So basically, 3/8" does not mean .375. 1/2" does not mean .50. I still don't understand that, but whatever. It must have something to do with the tapering, but I'll have to wrap my mind around it tomorrow.

Somehow, it seems that I need a 3/8" NPT according to this!

I bet if I found my fitting, it would be 1/4" NPT, which is .54". That's what it "falls into" the ".588" bore.

A 3/8" NPT slot fitting for a 1/2" hose should be easier to find, I would assume?

Probably this is what I need: https://www.summitracing.com/parts/fss-84712/overview/

Deathproof, does that hose end accept a 1/2" hose?