Jump to content

Engine thread sizes, oil pressure switch.


mpbarrett

Recommended Posts

Trying to find what size is the thread in the engine block used for the oil pressure switch? 
I have been thru a Vitesse and Herald workshop manual but cant find any thread details. The Vitesse manual has a list of all the torque settings for everything on the engine, and this also lists the thread size, but it does not include the oil pressure switch. I found one reference to the switch (in the electrical section) that states its a 1/8" 27 TPI American Standard Taper. At the moment mine goes into an adapter so no sure if the block thread is a taper thread or not.

So does anyone know what size the thread is? And, more generally, is there anywhere a list of the threads sizes used on Triumph cars? I don't have a parts list so maybe it in that.

thanks

mike

Link to comment
Share on other sites

I think that obscure electrical section reference translates as 1/8" NPT. The usual situation with pipe threads would be that the male thread (the switch) is tapered while the female (the block) isn't. All of mine have adapters in place (T-pieces for gauges) but all three are the same thread on all ports, and I'm fairly sure they're to that convention.

Edit: Apparently the taper-on-male-only convention is a BSP thing and doesn't apply to NPT, which would mean the thread in the block should be tapered. Hmm...

Link to comment
Share on other sites

BTW I am replacing the mechanical pressure gauge with an pressure transducer and need an adapter. I could buy one but as I have the time and the lathe and milling machine I thought I could make one :) I could take the old one  out and measure it...

Mike

 

Link to comment
Share on other sites

1 hour ago, NonMember said:

Apparently the taper-on-male-only convention is a BSP thing

Really?  I have taper taps for 1/8" and 1/4" BSP as well as parallel ones.......  I've only got a parallel die but that's just as it happens, taper ones exist.

Anyway, the oil pressure switch is definitely 1/8" and the switch itself has a taper male thread.  I'm not absolutely sure whether BSPT or NPT originally, but pretty sure BSPT (or even BSPP) screws in ok.  All the sideways facing gallery plugs on the 6 pot are the same but I think that on the 4 pot the others are 5/16" UNF and sealed with short bolts and copper washers.  On the 6 at least, the gallery end plugs are different again, and bizarrely, different either end.  

Nick

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...