Oil drain gearbox sump plug size?

[Bruss 579]

Does anyone know the diameter and thread size and form for the sump/drain gearbox plug?

 

TIA

[Ledlights 57]

I don’t know the thread spec but the head is 24mm A/F in case it helps.

[Bruss 579]

19 minutes ago, Ledlights said:

I don’t know the thread spec but the head is 24mm A/F in case it helps.

Thanks for that.

I see a fitting for the 400 gearbox cooler which screws  into the same place shows as a 18mm to 12mm reducer. I will have to take it out and check. Bgger really because I changed the oil a couple of months back and could have checked then. DOH.

[Julian73 153]

7 hours ago, Bruss said:

Thanks for that.

I see a fitting for the 400 gearbox cooler which screws  into the same place shows as a 18mm to 12mm reducer. I will have to take it out and check. Bgger really because I changed the oil a couple of months back and could have checked then. DOH.

While the side hole is an M18 thread (most probably M18 x 1.5), this is not the drain location but rather the fill for cars without the oil cooling circuit and the oil outlet for those with cooler. The actual drain is underneath the transmission and based on sharing same washer, would also be an M18 but probably with a magnet thus different part number.  With the oil cooler, the oil fill location has been moved to the cooler o-ringed return plug, fitted in place of the speedo-cable blanking plate/plug.

 

To the OP, if you are asking thread sizes in intent of retro fitting an oil cooler, please note that the secret sauce (not shown in the parts list, but highlighted in the Service Notes) is the pickup tube adapter that is required to be installed.  This fitting probably only insertable with trans torn apart allows oil to syphons up from bottom of sump, otherwise cooler pump would only suck air and foam.

[Bruss 579]

Thanks Julian

I was thinking of utilising the bottom drain plug for an oil cooler and returning via the top blanking plug. Also intending to put an electric pump, thermostat and in line filter directly after the drain plug and before the cooler, water cooled laminova  type. I Looked at the side exit but remembered your comment elsewhere re the service notes and the pickup tube.

 

[Julian73 153]

9 hours ago, Bruss said:

Thanks Julian

I was thinking of utilising the bottom drain plug for an oil cooler and returning via the top blanking plug. Also intending to put an electric pump, thermostat and in line filter directly after the drain plug and before the cooler, water cooled laminova  type. I Looked at the side exit but remembered your comment elsewhere re the service notes and the pickup tube.

 

Lotus uses a Mocal Pump 17-311, a filter and Toyo 15710-31021 oil heat exchanger mounted on a Local RFH2EB remote filter head, plus other bits and pieces.