Temperature adaptor thread size

[William2]

Can anyone tell me what the thread size is in the cylinder head that the temperature gauge adaptor screws into?

[billwill]

Its a standard plumbing part, you can get them inexpensivelyy in a plumbing shop.
3/8 BSP


See:
lotus-elan-f19/getting-ogu-roadworthy-again-t26101-90.html#p176702

onwards

[RichardHawkins]

William,

I measure my head as 3/8 NTP. BSP & NTP are very close at nominal size 3/8.

NTP is 18 threads per inch, and 0.675" diameter.

BSP is 19 threads per inch, and 0.656" diameter.

As these threads are often tapered, one will go into the other and tighten up giving the elusion of a fit.

Being Lotus it is always difficult to be certain, and quite possible that different ages of head have different threads. I would advise caution and try both BSP & NTP.

Richard Hawkins

[Lyn7]

Hi William, I agree with Richard, it is very difficult to be certain as the heads are getting older and PO will have done their own thing. I think in my current head I am using one BSP and one NPT. That is for heater and water temperature.

[rgh0]

I believe all the head plumbing threads are BSP while the blocks plumbing threads are NPT.

The mechanical temp sender adapter is special as the threads for the other male end are different.

cheers
Rohan