Dan,
I have been trying to get to the bottom of this Cervera tank outlet
thread question since Jim Parish's posting about stripping his fuel line
nut trying to connect to the tank. I have sent a couple email inquiries
to Jorge Cervera but have had no response yet. Jim contacted him
as was told the tanks have a 1/4" NPT thread on the outlet elbow,
which is why a 3/8" BSPP nut strips or cracks on them. 3/8" BSPP
is 19 tpi; 1/4" NPT is 18 tpi, and also tapered, so the further you try
to twist a BSP nut onto it the greater the splitting force on the nut.
One good source for a die would be the British Tool Company in
Grand Rapids, www.britishtool.com . He shows 3/8" BSPP dies in
his catalog. Other listers may be able to suggest alternative sources.
I have never tried to cut tapered American pipe thread to parallel
british pipe thread, so I can't tell you how you will make out going
from 18 tpi to 19 tpi. If you pursue this please let the list know how
you make out, as I consider this thread mis-match a pretty serious
safety issue and wouldn't mind hearing about good solutions. If the
line were to part from the tank while the car is moving it probably
would not result in fire, but the engine would certainly die, which
could be hazardous in the wrong traffic conditions.
Doug Reid, 18G Motorworks
>Date: Thu, 17 Aug 2006 18:42:12 -0700 (PDT)
>From: Dan Serrao <jobu1950@yahoo.com>
>Subject: Gas Tank
>
>Greetings to All,
> I purchased one of those steel gas tanks from Jorge in San Diego awhile
>back. I read on this site that the tanks he supplies have tapered threads on
>the outlet and that the line is straight threads. Question: Do you think I
>could get a tap and make the threads straight?? If so, does anyone know >the
size I should get?? I am fairly new to this site and just want to mention
>that I thoroughly enjoy reading the emails and I've learned so much. Thanks
>to all.
> Dan Serrao
> 1963 BJ7
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