Scott:
Yes, you may assume they are BPT. The US standard NPT is
compatible - with one exception. There is a second British standard pipe
thread which is NOT tapered. Best I can tell there is no equivalent US
standard. If the threads are straight BPT you will know it right away,
you will only be able to get about one turn before the pipe stops. While
you can get a seal, one thread is hardly enough to get you any strength
on the joint, and you are likely to break the thread should there ever
be any sort of side load on the joint.
The fitting from the water pump to the manifold coolant hose is
straight BPT, as I recall. My DPO put a NPT nipple into the water pump
and got it to seal (it was still on the car when I bought it). I went to
replace it with the correct fitting, and when I put my wrench on it I
pulled out the first 1-1/2 threads. My DPO also replaced the heater
valve adapter with an NPT nipple and an NPT pipe union from the hardware
store. That actually worked because the threads in the head and on the
heater valve are tapered, so the US bits fit just fine, even if they did
look like ghetto engineering at it's worst.
To answer your other question, the threads in the head and on
the heater valve are the same and are tapered BPT. Although NPT is not
identical to BPT, they are fully compatible and will happily co-exist.
Vance
-----Original Message-----
From: owner-6pack@Autox.Team.Net [mailto:owner-6pack@Autox.Team.Net] On
Behalf Of Scott Tilton
Sent: September 29, 2007 11:42 AM
To: 6 Pack list
Subject: [6pack] Pipe threads on the Heater Valve
Hey guys,
Is the male to female standoff that is sticking out of the head a direct
adapter? (are the male and female threads on each end of it the same?)
or does it convert from one thread size/standard to another?
Am I right in assuming that they are *British standard pipe thread*
(*BSP*thread) and not the *National Pipe Thread* (NPT) I'm likely to
find at home depot.
Scott Tilton
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