Spigot thread size?

[The Veg]

Anybody know the size of the straight-cut thread on this spigot from the water pump housing, to which the heater hose connects?

[ericbushby]

Apparently, if it is on the block it will be NPT (national pipe thread) because it is a Ford design but pipe threads on the cylinder head are BSP (british standard pipe) because it is a Lotus design and therefore british.
Remember that with pipe threads that the number is the bore of the pipe not the size of the thread.
I would have called that a 1/2" NPT hose tailpiece.
Cheers
Eric in Burnley

[Craven]

Front cover is Lotus so BSP

[rgh0]

Yes Lotus designed, cast aluminum parts are BSP - e.g. head, front cover, diff housing
Ford sourced cast iron parts are NTP - e.g. block , gearbox
Weber carbs are metric

cheers
Rohan

[The Veg]

Thanks gents. The reason I asked is because the spigot on the heater is 5/8" and this spigot is 1/2" for some strange reason. A PO just clamped the snot out of the 5/8" hose on it, but I'd rather have the same size spigot at both ends instead of re-bodging it.

[mbell]

It's standard to have 1/2" spigot and 5/8" pipe! The factory did the same over clamping.

I cheated with mine when fitting New hoses and fitted a length of 1/2" inner 5/8" outer pvc hose. Then inserted the heater house over that. Plenty of silicon grease to aid fitment and has been fine so far.

Did the same at the thermostat housing end too.

[The Veg]

Mine is 5/8" everywhere except this spigot, so if I can find a 5/8 spigot with that thread then life will be simpler, especially since that hose runs through nothing but difficult-to-access places where fitting a reducer and a short bit of 1/2" hose could be tricky.

[mbell]

I just put the hose directly over the spigot and used a single length of 5/8" heater hose.

Getting the spigot may be tricky on this side of the pond...

[mbell]

Adding a photo of the thermostat housing outlet to better sure what I did..

[CBUEB1771]

so if I can find a 5/8 spigot with that thread then life will be simpler

I searched for something like this for a very long time, this is a very common fitting for a 1/2" bore hose but not for 5/8". Finally Lotus Marques in Australia started machining their own hose adapters with the nipple end for a 5/8" bore hose. The threaded end is BSPP, I just can't remember the size right now and I am away from the garage. I think it is 3/8" BSPP which should have a thread major diameter of 0.656" (1/4 and 1/2 BSPP are 0.518" and 0.825" major diameter, respectively). I just looked at the Lotus Marques web site and the hose adapters are still listed but the photos make them look like they have tapered pipe threads which would be wrong. Try shooting them an email and enquire if they are still machining their own hose adapters. Don't worry about ordering from the US, I have bought quite a few bits from Lotus Marques, all high quality and they are pleasant to work with. The proprietor used to work in the US for one of the now-defunct computer hardware companies, Wang Laboratories if I recall correctly.

[The Veg]

Wang? No kidding? Haven't heard that name in ages! Back in the late '90s I worked in an office that was still using an old green-screen Wang IT system.

Thanks for the tip; will get in touch with LM.

[CBUEB1771]

Here is a photograph of the 5/8 hose X 3/8-19 BSPP hose barbs from Lotus Marques. A 3/8 Dowty washer is shown along side. When I looked at it again last night I realized that my memory must have failed me about Steve at Lotus Marques having these barbs specially made. There are stamped markings on the flats of the hex that make me realize this must be a commercially available item. However I must have looked at more than 30 on-line catalogues for hose and hydraulics suppliers in the US, Canada and UK and found only versions for 1/2 inch bore hose with a 3/8 BSPP thread. There was a comment about Lotus also clamping the daylights out of a 5/8 hose on the 1/2 inch barb. This is not what happened at Lotus. The original heater hose for the inlet side of the engine on a +2 (050P6006) is formed and has two diameters, 5/8" bore at the heater end and 1/2" bore at the front cover end.

[RichardHawkins]

I have just checked mine, 3/8 BSP.

As you are inthe USA I would think the answer would be to get a local machine shop to make what you need from hexagonal brass bar.

Richard Hawkins

[rgh0]

Another way would be to get 5/8 to 1/2 hose joiner and use two sections of hose to match the 1/2 inch connection you can get for the front cover and 5/8 connection for the heater.

There are people who make custom silicone hoses these days so you could probably get the hose needed made if no no one stocks anything suitable

cheers
Rohan