Morris Minor Owners Club

Hi does anyone know the thread size of the by-pass adapter in the head and also the pump as I want to do away with the by-pass hose as the two pipes are corroded very badly and blank the two connections whilst the head is off
Ian

I 'think' it is 5/8" UNF - BUT - you will struggle to het the old fitting out of the head - and the pump connection is surely cast as part of the pump........... Good idea to eliminate the bypass, but you will probably need to buy a pump sans connection, and drtill/tap the head to take whatever size of plug is to hand. Drill a couple of 1/8" holes in the rim of the thermostat to allow a little water to circulate on start up.

Bmc, thanks for the info yes i thought I would have to drill out the remains of the pieces , so wanted to know size of thread to work out drill size to just drill out bulk and then pick waste from threads, just with a quick glance at pump it looked like a pipe rather than a casting but will know better when i have a closer look was initialy going by exploded diagram in the manual.
Thanks for the tip about the holes in the thermo
Ian

It's 5/8"UNS not UNF. S=special.
See my earlier post.
http://www.mmoc.org.uk/viewtopic.php?f= ... NS#p358330

Regards
Declan

Here is a new attachment for the head, if your going to screw it out you may as well fit this.

http://morrisminorspares.co.uk/shop/pro ... b68121e599

DAVIDMCCULLOUGH wrote:Here is a new attachment for the head, if your going to screw it out you may as well fit this.

http://morrisminorspares.co.uk/shop/pro ... b68121e599

David,
That could be and highly likely is, the one that I mentioned in my earlier post that has the wrong thread. I would ask for confirmation that it's 16TPI and not 18TPI (UNF). The one I have fitted is the stainless steel one made by Jonspeed.
http://cgi.ebay.co.uk/MINI-CYLINDER-HEA ... 20b5e1c0b2


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Head stub removed, found bolt with similar thread cut short, cut slot for screwdriver, lots of red threaded pipe sealer on and fitted. Thread cut in stub on pump, bolt fitted with same sealer .Oh by the way the stub in head was blocked with crude and no water had passed that way for a long time

Well done! Highly unlikely you found a bolt with the strange 'UNS' thread - I do think it is 'UNF'.......

There is confusion on this issue but my measurements indicate it as being UNS and not UNF. Some of the mini supppliers are selling plugs as UNF. There's something wrong somewhwere. In my case the UNS thread fitted but the UNF didn't and I hope I'm wrorg.
Regards
Declan

How very strange !