Is there such a thing as fine thread NPT?

[Gbkeith]

I’m replacing a lift pump on a 4bt Cummins in a forklift. Old pump has 1/4 npt threads on both the intake and outlet sides. Intake had a hose barb fitting screwed in with the fuel line hose clamped to it.

New pump has different threads on the intake side. Looking at it seems to be fine thread. Outlet side is the same as the old one. NAPA does not have a fitting that’ll work. This seems like something where I have my head up my ass overlooking something obvious but I don’t know what it is. Is there a metric version of npt?

 

[D_JEEPER]

Maybe AN adapter required?

 

[AgitatedPancake]

Just to confirm - definitely still tapered? Not straight threads with a machined boss for oring or similar?

 

[Gbkeith]

I meant to post those in the original post.

Old pump.

New pump.

 

[JunkCJ6]

Banjo bolt setup on that side?

 

[Gbkeith]

Just to confirm - definitely still tapered? Not straight threads with a machined boss for oring or similar?

It looks slightly tapered but it’s hard for me to tell. I can’t see anything that looks machined for an o ring.

 

[Foxmxrcer]

British standard pipe? I think it's called? It's dumb and I can never find any fittings locally.... Or if it's straight, it's probably..... M12x1.25 banjo.

 

[willis_racing]

British standard pipe? I think it's called? It's dumb and I can never find any fittings locally.... Or if it's straight, it's probably..... M12x1.25 banjo.

Was going to suggest checking against BSP as well

 

[AgitatedPancake]

Agreed that it doesn't look machined for an oring or banjo sealing surface. BSP like these guys are saying sounds like a good thing to test next

 

[JR4X]

All the Cummins shit I work on is 100% metric.

 

[speed bump]

Can you take a picture inside the fitting. I would guess its a 7/16-20 or 24 from your description.

 

[jeeptj19992001]

Looks like casting treads are fed

 

[665.0coupe]

All the Cummins shit I work on is 100% metric.

Hopefully that means just BSPP or BSPT and not JIS.

 

[Sceep]

Ram the old fitting in there for some good ol Natures Loctite. Take care not to split the housing with the tapered thread.

Goop some JB Weld on the threads for added sealing.

 

[Gbkeith]

All the Cummins shit I work on is 100% metric.

I’m pretty sure this same basic lift pump is used on case and John Deere stuff also. It may be that the one I pulled off came from something else. I know the inline filter is not the factory sky trak set up.

 

[Gbkeith]

What kind of shop carries BSPP stuff?

 

[det107]

Ram the old fitting in there for some good ol Natures Loctite. Take care not to split the housing with the tapered thread. Goop some JB Weld on the threads for added sealing.

If the fitting threads are brass (soft material), just put in-

 

[Steve300xcw]

What kind of shop carries BSPP stuff?

not napa

Hydraulic or a riggin shop will know what it is.

 

[denis]

British standard pipe?

FWIW, BSP and NPT are within 1 TPI from each other, you would barely notice the difference.

 

[JR4X]

FWIW, BSP and NPT are within 1 TPI from each other, you would barely notice the difference.

That’s threads per inch but you definitely notice the difference in diameter

 

[Gbkeith]

FWIW, BSP and NPT are within 1 TPI from each other, you would barely notice the difference.

It’ll start almost a full round.

 

[Steve300xcw]

I'm also impatient and woulda ran a tap in there in hopes of making threads that fit the shit I already had

 

[Gbkeith]

I'm also impatient and woulda ran a tap in there in hopes of making threads that fit the shit I already had

Bout to try that

 

[Bacho]

That barbed fitting appears to me is improper. It looks like it’s been forced there. My lunch money says it requires some sort of banjo bolt fitting.

 

[subybaja]

Tap it and forget it. Who cares what it was.

 

[TrailTamer]

I used BSPP fittings on my 6BT. BSPT fittings can be fitted into BSPP.

The lift pump port's face don't look like for BSPP as its rough casting. BSPP fittings are to seal on the face.

I'd say get a BSPT, or just rethread it with a tap to 1/8" NPT.

And the original fitting looks like 1/8" NPT jammed into 1/8" BSPT, as there's a good bit of threads left. IMHO

 

[Gbkeith]

I used BSPP fittings on my 6BT. BSPT fittings can be fitted into BSPP.

The lift pump port's face don't look like for BSPP as its rough casting. BSPP fittings are to seal on the face.

I'd say get a BSPT, or just rethread it with a tap to 1/8" NPT.

And the original fitting looks like 1/8" NPT jammed into 1/8" BSPT, as there's a good bit of threads left. IMHO

I’d just hand started the fitting a couple rounds for the picture. It goes in farther.

Rethreading it did not work out well. Amazon is sending me another one.

Put the old pump back on and running it a little longer.

 

[DVanVorous]

What kind of shop carries BSPP stuff?

Hydraulic supply places mostly...9x out of 10 they also have the ability to check the thread to confirm what it is as well. Annoyingly enough BSP is whats used as the "metric" pipe thread standard overseas. Major PITA to find fittings or even adapto widgets to fit them. BTDT, folks that peddle "swageloc" fitting have them but it's rarely a stock item.
There IS an ANSI straight pipe thread one runs into on hydraulics stuff now and again when the pressure isn't particularly high. Found those at hydraulics places.
The other is the more common O ring seal which is a conventional straight thread with either the seal area relieved like a flat head screw angle seal surface for seating or the flat seal area type if the male fitting has an oring groove cut in it...Found those at both the same places that carry Swageloc and most any hydraulics place.

 

[Roc Doc]

Keep in mind that both the male and female parts of a threaded NPT connection are threaded, which is a dumb design, especially for PVC.

 

[SKULLYOTA]

Echoing what everyone else said about BSPP and BSPT, should be easy to find at one of the hydraulic parts houses online. I had to buy a bunch of it for my Chinese air locker compressor.