Did a search mostly came up with, "try hooking up a different gauge". But this one is brand new mechanical.

::::Rundown:::
Just installed a new Stack Mechanical oil pressure gauge, ditched the plastic garbage and used braided line.

On cold startup pressure is at 60psi like normal, but if I give it gas it will make a large sweep to around 85 psi then jump back to its 65-70psi where it should be.


It seems as though it may have a bubble in the line. That is how its acting, and that is what i first assumed, but when i searched i found people saying stuff like debri in the pickup etc.

two parts of the install would be conducive to air bubbles getting into the line::::

*I T'd into the back of the block, and the braided fitting is running vertically off the T.

*I also have about an extra foot of braided line and it is coiled once loosely. all together it is 6 feet of line.

My question is it even possible to get air bubbles in the line, or do i need to be looking for something else?

 

i got news for you buddy...when you step on the gas, oil pressure goes up...that's normal. congrats on a successful oil pressure gauge install

 

sweet ****.

 

Is this an autometer gauge by any chance?

 

From what I read, it's a Stack mech. gauge.

Oil pressure fluctuates quite a bit as RPMs change, as you've already seen. You'll also notice that oil pressure at idle once the engine is up to operating temp is much, much lower than 65 PSI. Mine is usually around 25 PSI or less. You can see just how much oil pressure fluctuates by looking at my data logs from laps around TWS here in Texas (around 50 to 90 PSI as I go around the track).

 

Yes, oil pressure is supposed to rise with RPM, at least you hope it does.

Reason I asked is I have seen a number of Autometers display a weird quirk where they will rise to a certain pressure and then SNAP back down to a lower reading. I dont know what exactly causes it, but I have seen it.

 

perhaps this "snap" action is a result of the oil pressure relief valve opening?

 

I thought this too, but never investigated, always thought it was much to fast for it to be the pressure relief valve.

 

It'd be cool if someone could do a little test for us!

Record some setpoints for rpm and pressure, then maybe add a shim to the relief spring,then see if the same "snapping action" occurs , but at a higher pressure.

A datalogging setup like 117 was describing would be perfect!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Combustion Contraption &raquo;</TD></TR><TR><TD CLASS="quote">Yes, oil pressure is supposed to rise with RPM, at least you hope it does.

Reason I asked is I have seen a number of Autometers display a weird quirk where they will rise to a certain pressure and then SNAP back down to a lower reading. I dont know what exactly causes it, but I have seen it. </TD></TR></TABLE>

my auto meter did that and it was a crack in the T-fitting on the block.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by projectTeG &raquo;</TD></TR><TR><TD CLASS="quote">

my auto meter did that and it was a crack in the T-fitting on the block.</TD></TR></TABLE>

did it leak at all? im all tightened up, but that adds merit to my airbubble theory.

 

No crack here, no leak, and it wasnt a tee fitting, it was the sandwich plate style.

 

speaking of sandwich plate style, will one of those just spin right on to my existing OEM oil cooler plate or do i have to choose one or the other?

 

i have a similar situation. When i first start the car oil psi is at 60psi as the car warms up it drops slowly to about 25psi. once im on the road it fluctuates with my rpms which is fine. but once i get to a full stop my psi reads alil under 10psi. IS THIS NORMAL?


Modified by DANNYCAVS at 6:37 AM 6/12/2008

 

Could also be the bypass inside the oil filters too. Maybe revving up on cold oil pops open the bypass valve and the pressure drops suddenly? Or is the pressure sensor after the oil filter?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by flyrod &raquo;</TD></TR><TR><TD CLASS="quote">Could also be the bypass inside the oil filters too. Maybe revving up on cold oil pops open the bypass valve and the pressure drops suddenly? Or is the pressure sensor after the oil filter?</TD></TR></TABLE>

hmmm that sounds like a feesable theory. it is to the left of the oil filter. it is all tapped into where the OEM preassure sending unit is usually located.