Morris Minor Owners Club

The threaded hole in the top of the Marina thermostat housing is indeed normally fitted with a blanking plug which can be removed to top up and check the coolant level.

The way I got around the difference in size of the thermostat housing top hole and the size of the hole required for the transmitter was to purchase a brass blanking plug https://www.ebay.co.uk/itm/Land-Rover-D ... 2749.l2649 and drill and tap to suit either the adapter (capillary) or the transmitter (electrical).

Also done by Sandun if you can find his thread.
Picture by Sandun
I put this link in as it shows the Marina thermostat housing with the adapter fitted and placed on a head.

viewtopic.php?f=4&t=67822&p=618567&hili ... ng#p618567

I drilled the three 5/16" stud holes to 3/8" to give a better alignment between thermostat housing and Minor radiator.

Make sure that the transmitter does not foul the thermostat when the thermostat opens.

Mike,
The one that I have fitted is a Intermotor 52760 Temperature Transmitter. This fits into the standard head threaded boss. £6.50 off Amazon.

Does your 948 not have a plug at the front of cylinder head?

JOWETTJAVELIN wrote: ↑Sun Aug 25, 2019 12:09 pm Does your 948 not have a plug at the front of cylinder head?

Not unless it's been modified with a latter head. My SII had a 948 Goldseal fitted at some time in it's life, I'm not sure when, and that had the blanking plug, but original Minor Era 948 engines did not.

Strange, I wonder when they were introduced. My 948 has a blanking plug but it is in the last 1000 of production if that makes any difference.

A photo of the head with blanking plug shown and details of the head casting number would be appreciated.

How difficult is it to remove the blanking plug for the temp sender? I had to weld a wheel nut on to remove the blanking plug so that I could fit a bypass hose on a 940 head.

I have never had any difficulty in removing the temp gauge blanking plug as it is a much more solid item than the bypass hose stub and has the benefit of a hexagon head for a socket or spanner to grip against.
Temp gauge transmitter hole (940 head) at bottom right of photo below.

Does your 948 not have a plug at the front of cylinder head?

Hi,
No holes or blanking plugs on mine...
Best wishes,
Mike.

My 1098 engine on my 63' has no thread for a temp sender. It's the original engine.

The 1098cc engine is/should be fitted with the 12G202 cylinder head which has a temp transmitter fitment hole just under the thermostat housing on the spark plug side of the head.

Postby paul 300358 » Sun Aug 25 2019 9:22 am

Mike,
The one that I have fitted is a Intermotor 52760 Temperature Transmitter. This fits into the standard head threaded boss.

Hi Paul,
This will fit my Marina housing?
Many thanks,
Mike.

The standard temp gauge hole/thread in the head is 5/8" UNF and the hole/thread in the Marina thermostat housing is 1/2" BSP (13/16").
The hole in the head has a seat for the transmitter to seat and seal against. The Marina thermostat housing does not have a seat which may make it difficult to seal the transmitter in the housing.
The only way round it is to make/use an adapter to suit either the capillary type transmitters or the electrical type transmitter.
When the early capillary type transmitter is fitted to the head there has to be a another 5/8" UNF male to 1/2"BSP male adapter screwed into the head to allow the 1/2" BSP female nut that secures the capillary tube bulb to be attached.
Later capillary type transmitters when fitting to the head will also need adapter https://www.moss-europe.co.uk/adaptor-t ... soc=506734
As the Marina Thermostat housing thread is 1/2" BSP a double ended 15mm pipe joiner can be screwed into the housing which will accept the early capillary tube transmitter and securing nut.
When fitting the capillary tube - the clearance between capillary bulb and thermostat must be checked.

What's a 1/2 inch NPTF? https://www.carbuildersolutions.com/uk/ ... X8QAvD_BwE

paul 300358 wrote: ↑Tue Aug 27, 2019 9:44 am What's a 1/2 inch NPTF? https://www.carbuildersolutions.com/uk/ ... X8QAvD_BwE

It's American 'National Pipe Taper Fuel'. How that compares to 'British Standard Pipe', I've no idea.

Perhaps your link is for people maintaining vintage US vehicles.

Its interesting as both 1/2 inch NPTF and 1/2 inch BSP have 14 tpi and 1.8143mm thread pitch. But they could be slightly different diameters.

paul 300358 wrote: ↑Tue Aug 27, 2019 10:38 am Its interesting as both 1/2 inch NPTF and 1/2 inch BSP have 14 tpi and 1.8143mm thread pitch. But they could be slightly different diameters.

I just found this:http://www.flow-controls.com/news/The-d ... on-20.html

If I read this correctly, at 1/2" and 3/4" they are the same

Where there is a difference is that the American one has the F suffix, indicating it is for 'Fuel' which are designed for a dry interference fit between male/female threads, whereas a normal NPT/BSP would have space at the peaks and troughs of the thread to use a sealant, e.g. tape or paste.