Oil pressure gauge question

['76mintgrün'02]

2 hours ago, John76 said:

BTW: If your oil pump pressure relief valve is functioning as designed, you should not get anywhere close to 100 psi.

If you do, you'll blow the oil filter gasket long before the gauge or tube explodes in the cockpit.

 

My relief valve is sticking, but seems to get freed up once the oil's up to temperature.  The pressure rises with rpms and spins well past 100 if I am not careful.  My filter's on tight and that seal's been fine, but I've got an oil leak coming from the crank seal now.  I suspect that's  mostly happening during the warm-up stage.  I drove it for almost ten years, before adding that gauge; undecided about where to put one.  That one's just hanging from the underside of the radio, on a rare-earth magnet, with another between the gauge and the catch-can lid. 

 

[Son of Marty]

If you over pressure your mechanical gauge it will damage the bourbon tube that controls the indicator needle and it'll no longer be accurate. 

[jimk]

Always noticed at eye level and adjustable.

[Hans]

1 hour ago, Son of Marty said:

If you over pressure your mechanical gauge it will damage the bourbon tube that controls the indicator needle and it'll no longer be accurate. 

Tell me more about the bourbon tube...

['76mintgrün'02]

15 minutes ago, Hans said:

Tell me more about the bourbon tube...

 

                                    

 

[Son of Marty]

The Bourbon tube, as in the pictures Tom provided, is a curved bit of tube usually copper that will start to straighten out as pressure is increased and once it stretched beyond it's range it looses accuracy. Bourbon gauges do work harden over time also, I don't know how many cycles it takes but it does happen.

[jimk]

1 hour ago, Hans said:

Tell me more about the bourbon tube...

86 proof.

[ErnieThe02]

17 hours ago, '76mintgrün'02 said:

I should probably fix my leaker too.  I gave the plastic tube a little stretch to straighten it out and that may have thinned it.  Is the little brass crimp fitting in the joint reusable?  Can I just shorten the tube and try again, or do I need to make or buy a new little brass piece? 

 

 

I've just been emptying the Altoids tin every four months or so.   

This is my favorite response/solution to date!

Made my day.

['76mintgrün'02]

20 minutes ago, ErnieThe02 said:

This is my favorite response/solution to date!

Made my day.

 

Thank you.  It makes me chuckle too, which is probably why I haven't tried to fix it yet. 

 

It also took me a while to get around to sealing up my steering box.   

 

[TobyB]

BourDon tube, you alcoholic yay- hooz!  

 

(it's gin and tonic weather over here, anyways)

 

Mr BourDon can usually take about twice maximum indicated pressure before he...  ummm...

...herniates?

 

t

 

[ray_]

5 hours ago, John76 said:

Yeh Toby, but you also be wise. 

And surly

 

😁

[Mike Self]

On 8/15/2023 at 5:22 PM, jimk said:

Tell me more about the bourbon tube...

A bourdon tube is a mechanical analogy to the bimetal strip used in old turn signal flasher relays and the early 2002 wash/wipe relay (silver can on the firewall).  One end of the strip is free to move, and at rest touches a fixed conductor.  The bimetal strip is composed of two dissimilar metals bonded together.  When an electric current passes through it, the metals heat at a different rate and the strip bends, breaking the connection.  The bimetal strip then cools, straightens up and makes contact again.  This is how turn signals blinked, and the wash/wipe made several strokes before transistorized circuits took over the chore.

 

2002 trivia for the day,

 

mike