Mechanical Oil Pressure Gauge conversion

[r32flow]

Here's what mine looks like. And yes my truck leaks oil.

 

[r32flow]

That's looking straight up at it.

 

[scott2093]

Here's what mine looks like. And yes my truck leaks oil.

4wd...
I'll go look at mine...

 

[Schurkey]

Yes, you can make it as long or short as you want to, just make sure you bleed all the air out for more accurate readings.

Every time you shut the engine off, you're likely to put air back into the tubing connected to the gauge. After a while, it's got heaps of air in it.

Bleeding the gauge does nothing for accuracy EXCEPT that it makes the gauge react a tiny bit faster to sudden fluctuations. And you'll have to bleed the gauge plumbing every few weeks to minimize the amount of air in the tubing.

I don't think it's worth the effort.

That's looking straight up at it.

You're looking at the oil filter adapter, not the block. Look from the side, and look at the block, not the adapter.

 

[scott2093]

Here's where mine is in relation to the filter

 

[scott2093]

Bleeding the gauge does nothing for accuracy EXCEPT that it makes the gauge react a tiny bit faster to sudden fluctuations. And you'll have to bleed the gauge plumbing every few weeks to minimize the amount of air in the tubing.

I don't think it's worth the effort.

So the 12 inches of air before my meter is normal?

 

[Road Trip]

So the 12 inches of air before my meter is normal?

I've observed this same air bubble made visible when the translucent nylon tubing is used. I had
similar concerns as yours, so I went to the extra effort to purge that air bubble.
Here is what I observed afterwards:

* With a incompressible pure liquid coupling, the gauge pointer would show the minor
pressure ripple (inconsequential variations) as the gears were pumping the engine oil at a
slow hot idle. (See attached for a view of the gears inside a standard SBC oil pump.)
Note: Some might describe the view as 'needle flutter'.

* As Schurkey mentioned, the air bubble always came back after a few driving cycles.
The air bubble was much larger engine off (zero oil pressure) vs full oil pressure at
~2500 rpm. (55-60 psi)

* I also noticed that the needle flutter almost completely disappeared with the air bubble
in series. Since the needle flutter wasn't conveying any useful information, I actually felt
that the air bubble was more feature than fault. As in I quit worrying about the air inside
the tubing affecting the accuracy of the reading. Instead, it was acting as a small shock
absorber for transients, but at the same time not affecting overall accuracy at all. (!)

****

You didn't ask for an opinion on the nylon tubing, but after a buddy had a damaged
nylon tube failure making a memorable mess inside his engine bay, I started recommending
either the copper tubing or woven stainless upgrade between engine and gauge. (I am in
agreement with @FLGS400 in his reply above.)

Having shared this, I've also run for literally years on nylon tubing with nary an issue. But I did
obsess over the routing during installation, including a rubber grommet where it passed
through the firewall. Just keep in mind that exhaust heat and sharp edges anywhere can/will
make the nylon fail in flight, so respect these limitations & you will be alright.

But I'd rather share both experiences and let you make the final decision.

Bottom line = good on you for wanting the no-nonsense way to monitor your engine oil
pressure. For any engine I really care about (normally any engine I've had apart and invested
a lot of parts, machine work, & effort into) ...I will install the mechanical oil pressure gauge just
for the added peace of mind/less guesswork. I have yet to augment the factory electric oil
pressure gauge on the chore truck, but it starts so quietly and the pressure comes up immediately,
so unless I get the chance to refresh that motor I'm just going to get by on the stock stuff for the
near term.

But I dream about the day when I open the driver's door and the first thing I see is a mechanical oil pressure
gauge to monitor what's going on inside the big block. This will mean that good things have happened
under the hood for yours truly.

Please be sure to post some pics of the finished installation for our viewing pleasure. :0)

Cheers --

 

[scott2093]

Bottom line = good on you for wanting the no-nonsense way to monitor your engine oil
pressure

Thanks for the info again. Obviously you're the reason for me getting one. It is temporary atm and just sitting in my ash tray with no lights..I'm planning a dash swap soon so will do a proper install then. Been eating at me to get a look and yes, the oil sender for the gauge on the dash is shockingly useless.l..the new sender, both GM is totally different reading than the old...I definitely don't have 80psi at startup...lol at least the old one said 60 which is more in the ballpark....

I need to let things warm up and take it for a drive... Hoping things will look good once warmed up.That's the curiosity for me obviously... Hoping it'll be good enough news....
Clear tube makes me want to take the test drive to get some oil for a change....
Been running that rislone for a bit...maybe a good idea....

 

[FLGS400]

I firmly believe what Shurkey stated, and have never bled one of those oil pressure gauge lines. Never had an issue with readings either.

In scott2093's photo, it's the port with the NPT plug. Mine looked the same before I installed the oil pressure gauge.

 

[r32flow]

Thank you guys, I installed mine this afternoon. Bad news is, i still have low oil pressure. It reads exactly what my factory guage reads.

But I will say, I totally forgot to bleed the line, and the guage works perfect.