The Fordson Tractor Pages Forum

Which thread is right for the oil pressure switch? 1/4" BSP or 3/8" UNC/F. Two types are advertised.

Regards

Ian

depends on what one fits your block the early dextas had the smaller one the later
type the bigger, if my memory serves me right dexta an super after april 62 had the bigger one

I have fitted my new iol pressure switch and I can confirm that the later (1963) is 1/4" BSP.

Regards

Ian

The story continues... the new oil pressure switch was leaking between the black plastic and the hexagon as soon as I looked at it 5 mins after starting, I called Agriline and the man apologised and offered to send me another straight away, when I fitted this it leaked also.


I rang again, this time the man said that these are being sold to others who haven't had a problem, and wondered if my pressure was too high, however he very willingly offered to send another but suggested one from an earlier batch with a zinc plated nut, the first two had brass nuts.

This got me thinking so I put a gauge on before fitting the 3rd switch. The pressure (around 60 psi) was higher than I expected for an old engine all though it hadn't really warmed up, but not unreasonably high in my view. The pressure was however pulsating, is this normal? see the videos, the first at medium revs, the second at high revs. Out of interest, where is the relief valve?

https://www.youtube.com/watch?v=TtLl8Jl-xyA

https://www.youtube.com/watch?v=lv-dt1GCAJ4

I fitted the 3rd oil pressure switch and so far it is holding and working. So I think there may be problem with the batch of switches, I will let Agriline know but at least there was no quibble over the replacements.

Regards

Ian