Fill and Drain Plug size on UN1 Gearbox

dermot · 11-19-05, 02:10 PM

My UN1-26 gearbox is currently away being rebuilt. Was thinking of fitting an oil cooler assembly when it comes back. It is going into an Esprit. Basic cooler set using Mocal Oil pump, 13 row oil cooler, triggered at 100 deg C. Easiest way to set it up would be to use the existing fill and drain plugs.

Since i don't have the box, I do not know what size fittings to order. Size and thread type for the fill and drain plugs please ?

Dermot

Howard Jones · 11-21-05, 10:46 PM

My UN1 has a 1/4" pipe thread ( 1/4 ID X 18 threads per inch ) plug both in the drain and fill ports.

BruceLambo · 05-05-06, 09:27 AM

Ive added an oil cooler to my UN1 13. I used right-angle swivel unions and threaded the box housing to suit. I put the inlet (return) on the side of the rear cover pointing straight at 5th gear. The outlet is on the other side of the drain plug under the crownwheel. As the cases are 4mm thick, I welded a new aluminium plate inside where the new union was to go and then drilled and tapped it for a 3/8 PT thread. This gave the unions more to 'bite' onto. The idea of having those positions are so the oil cooled the most strained gear of the box, and so cool oil would flow through the whole box, not from halfway if just put in where the filler goes. I also drilled and tapped a spare mounting casting for a temperature thermostat.