14 replies to this topic

[JonnyAlpha]

Hi;

 

Just about to finally connect up my custom dashboard Oil Pressure Gauge and was searching for a reminder on how to fit it. 

We don't have a sticky on this but there area few old posts explaining how so I did some looking.

 

This thread from back in 2006 has a good write up, but I have just found a video here.

 

Quick word of warning - the gentleman in the video uses the 'F' word once.

 

I too bought the MiniSpares nylon pipe, but my SH gauge came with a braided one which I will try out first.

 

Enjoy.

 

 

 

 

 

 

 

 

[JonnyAlpha]

Ah - problems.

 

Dismantled my dash and fitted the nylon tubing to the back of the gauge. Ran it through the bulkhead and then started to prepare the old oil pressure gauge.

 

Cleaned up externally and applied some Plus Gas and then using an 11mm spanner (I think) I undid the oil pressure sensor. It wasn't too stiff and came out OK, however on looking at the end of the sensor the last time it was installed (not by me) it would appear that the threads had been stripped. From what I can see inside the threads in the block looked OK but the new T Piece just did not want to go in (could't start the threads).

 

Now in a bad place!!

 

In order to drive the car I put some PTFE tape around the old sensor and refitted it carefully - it is barely in but OK for now.

 

Problem is what do I do now?? 

[Stu1961]

Best bet would be to run a tap down the hole in the block to clean the thread out pretty sure its 1/8" BSPP, if you are careful enough and put a blob of grease on the end of the tap you will avoid getting any swarf in to the oil gallery. Remove the blob of grease carefully with something pointed such as a scriber point after removing the tap.

[carbon]

My suggestion here would be if the oil pressure sender thread in the block looks OK then DO NOT use a tap in the threaded hole.

 

Reason for emphasis is that it is almost impossible to stop small pieces of swarf or rust dropping into the main oil gallery, and from there it's only a short hop down to the main bearings. Just one small piece of rust or swarf in the wrong place could cause a lot of grief.

 

My suggested next step would be to get a standard oil pressure sender, and see if this screws smoothly into the block without forcing.

 

There are different thread types for oil fittings, and some of these are very similar to one another but not identical.

[JonnyAlpha]

Just messaged MiniSpares. Looking at replacement oil sensor the threads look tapered but the T Piece (part no TP)is parallel.

Does it need an adaptor.

[carbon]

You need to get a T-piece with the correct thread for the block.

[Spider]

Yes, the thread in most blocks is tapered (1/8" NPT) and most adaptors have a parallel thread.

 

The cars that were factory fitted with capillary Oil Pressure Gauges had a parallel thread here - just to do our heads in!

[JonnyAlpha]

This is the Mini Spares Oil Pressure Switch and this is the 'T' Piece. 

 

This is the Somerford one which looks tapered.

 

I'll take a pic of mine. 

 

End state is I need a new Oil Pressure Switch anyway. 

[JonnyAlpha]

Hi;

 

Does anyone have a 1/8 x 27 NPT Tap and Die. I have removed my Oil Pressure Switch and found that whoever last fitted it has overtightened it and has stripped the thread off of the ends. The new Oil Pressure Switch or the T Piece adaptor will not thread into the whole. From what I can see the thread looks OK but probably needs cleaning out?

 

Preferably borrow and in North Devon?

 

Supposed to be going to a classic car show in North Devon on Sunday :-(

 

Link to my post on the subject here.

[JonnyAlpha]

had a bit of luck today, spent some time trying to clean out the threads but no joy. Finally decided to speak to my local garage and they asked around for me and managed to borrow a 1/8 x 27 NPT. Tentatively cleaned out the thread and I now have a working Oil Px Gauge

 

Put PTFE tape on all the threads but still have oil leaking where the adaptor enters the engine block. The adaptor is not tight as I wasn't sure how much I should screw it in and wanted to be very careful with it. How far in should it go and how tight should it be?

 

P.S. Oil running at about 65 lb/ft

[Rorf]

You certainly do not want this popping out when you are on the road. I would make sure it is tight and not leaking or you must make another plan. As mentioned be very careful of metal swaf getting into the oil gallery.

Edited by Rorf, 07 June 2018 - 05:57 PM.

[Spider]

 

Put PTFE tape on all the threads but still have oil leaking where the adaptor enters the engine block.

 

How far in should it go and how tight should it be?

 

PTFE Tape won't seal Oil. There's also a good chance of some of it going where you don't want it, ie, down the Oil Gallery.

 

Also, when using a tape and if you have a Switch or electric sender that Earths via the block, there's a chance that the tape will insulate it from that Earth.

 

I use Loctite to seal these fittings with and being what they are and where they are, then these no need to go ape tightening them.


<Edit: as there was two threads running on this, albeit with different titles, I've merged them both here >

[JonnyAlpha]

 

 

Put PTFE tape on all the threads but still have oil leaking where the adaptor enters the engine block.

 

How far in should it go and how tight should it be?

 

PTFE Tape won't seal Oil. There's also a good chance of some of it going where you don't want it, ie, down the Oil Gallery.

 

Also, when using a tape and if you have a Switch or electric sender that Earths via the block, there's a chance that the tape will insulate it from that Earth.

 

I use Loctite to seal these fittings with and being what they are and where they are, then these no need to go ape tightening them.


<Edit: as there was two threads running on this, albeit with different titles, I've merged them both here >

 

 

Ah yes;

 

When consulting my Haynes Manual (to confirm the wire for the Px Switch) I noticed it said to use Loctite.

Any particular type?

 

There are so many

 

Loctite

 

Looks like I'll need to disassemble it and rebuild.

 

Thanks  

[JonnyAlpha]

Oh another question. 

 

The capillary gauge is working (about 65lb / ft when Engine is driving) but the original warning light is not coming on when the ignition is switched on.

The original Px Switch only had only one spade terminal, like this, but the recommended alternative has two. It is this one. Does one side need earthing?

 

Thanks 

[Spider]

Loctite - I just use 243 for this, the same one I use for locking the Cam Nut, Harmonic Damper Bolt, Flywheel Bolt and even for sealing the Freeze Plugs with. Don't use a high strength grade as they usually have less gap filling qualities, which is what you need here.

 

In regards to your Switch appearing that it doesn't work, it could be that it's now insulated by the PTFE Tape. Remove it and put a meter across from the terminal to the body of it, you should have a circuit.