Engine/Transmission (1994 - 1998) installed a mechanical oil pressure gauge...

[Forrest Nearing]

I'd read on the board in the past that the factory oil pressure gauge is more of a dummy light than anything else, and that never sat right with me... I run a mechanical gauge on all my hot rods, and I got the stuff together to run one on the truck a while back...



finally got around to installing it today.



WOW, I didn't realize just how much discrepency there really was!!!



I was surprised to see that it took a sec for oil pressure to build and the needle moved slowly. the truck and oil were already hot when I installed the gauge. I attribute the slow movement to the gauge itself (Sunpro full sweep... different gauges react differently) and the fact that the line is LONG.



I was pleased to see that hot idle at ~700rpm is about 32psi... and it just goes up and up from there... by about 1500, I think I'm seing 60psi or so... I've seen as much as 80 and haven't taken it over 3000rpm yet!



I have been questioning the condition of my bottom end because the thing PUMPS oil vapor out the blowby tube and coats the underside of the truck w/ oil... I just keep the oil level topped off. the truck runs great, and it looks like the oil pump and the bearings are in good shape!



I realize much of this has been covered in the past, but I felt compelled to post up due to the HUGE difference in readings from the stock gauge to the mechanical. I hadn't realized these engines run so much oil pressure!



Forrest

 

[Gary - K7GLD]

ACTUALLY, I see pretty much the same on my stock guage as you report with the mechanical, but nice to have both. And I think it's the 3rd generation trucks where the oil pressure guage is pretty much a dummy, set up primarily to read what the owner will be happy with...

 

[Forrest Nearing]

my stock gauge just holds steady at 45psi... wish I could have relied on the stocker (it's positioned better! LOL!) but at least now I KNOW what's going on in there!

 

[CumminsPower98]

My '98 reacts to changes in RPM and heat so I'm not too worried about it.

 

[bmoeller]

Originally posted by Forrest Nearing

my stock gauge just holds steady at 45psi...

Same here.

 

[JGheen]

Forrest,



Where did you tap your line into? I am going to do the same thing soon and noticed there is an 1/8" NPT plug on top of the oil filter, where the turbo oil feed line comes out of it. Is that where you tapped into?



Joe

 

[Forrest Nearing]

yes, that's where I tapped into. I did a search on the forums, and that seemed to be the consensus.



Forrest

 

[drrhoades]

Did you guys intall any sort of a buffer like with a fuel pressure gauge inline to keep the pulsations down.



Thanks,

Doug

 

[Forrest Nearing]

there aren't any pulsations with an oil pump... it's a steady flow type pump.



Forrest

 

[drrhoades]

Thanks thats what I thought but it never hurts to ask.

 

[JGheen]

Hey Forrest, those threads where that plug is on top of the oil filter housing are 1/8" NPT, right? Just want to be sure since I am ordering fittings and a gauge today.



Thanks, Joe

 

[Forrest Nearing]

yup. most gauges should come with a 1/8" NPT fitting.



I used copper line instead of the plastic that comes with them... it transmits more noise, but I don't trust those nylon lines ever since one let go at the most inopportune time on my brother's car! LOL!



Forrest

 

[bmoeller]

Originally posted by Forrest Nearing

... ... . but I don't trust those nylon lines ever since one let go at the most inopportune time on my brother's car! LOL!

I know the feeling. Had that happen on my Last gasser truck. The gauges were above my CB radio. The line broke right behind the compression fitting. Had about a quart of hot oil hit the top of the radio and my boot. Made a nice mess on the carpet. Needess to say, the mechanical gauges were replaced with electronic ones.