Normal temp sender into SPI head. What size tap?
Turbo Mini Forums

Evening folks.

I'm just building up my new engine this evening, to find that the MED roadcomp head I've got was originally ground from an SPI base, as a result, it didn't have the heater take off at #4 end, and it doesn't have a through hole and thread for the Mini water temp sender.

I've drilled the hole for the heater hose take off, and cleaned out the threads with a tap, but I don't have a tap big enough for the temp sender hole.

Any suggestions on what size tap I need would be great.

Cheers

Nick

Mr. Prawn, the friendly Crustacean- slowly making steps towards forced induction.

If it's to fit a standard sensor (ie, pre injection that goes in the head from the front below the thermostat housing) it's 5/8" UNF.

Schrödinger's cat - so which one am I ???

5/8"UNF as above, but you might be surprised to know that the SPI Coolant temp sensor is also the same shape and size as a carb gauge temp sender

I would drill an 8mm hole first (or what ever size the small protruding bit is on a temp sender) then a 14mm hole 10mm deep NOT!! including the cutting point (IE about 15mm deep at the center and 10mm deep at the outer edges) and then tap the hole and finish with a plug tap thus leaving a seat for the temp sendor to seal on

Edited by Sprocket on 11th Jul, 2010.