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Discussion Starter · #22 ·
Thanks Ken. I'm still struggling to determine the flow direction past that port in the oil filter adapter without having it in my hands and really eyeballing it, but I reckon it'll be "close enough" for my application. I was chatting with Ed Runnion on Facebook who is running his oil temp sensor in that filter adapter port.
I'm running Mobil1 which should be ok to 300F+, and I've never seen north of 250 at the block port, so it's mostly for reference to see if it's abnormally high, etc. I can always extrapolate any temp difference between the two sensor locations also, since I know where what temps I typically see under varying conditions.

The 'T' is a cool idea, but it's pretty cramped back there as it is, and yet another part I'd have to track down and install before I leave for Nats in a week.
BUT..... I'm curious if you have any idea of what size 'T' fitting I'd need, or what to search for online?
 

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Brian, I have another picture but the system won't let me load it now, I'll try later or send me a private message and I'll send it to you.
 

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199976

I did this about 15 years ago so I don't remember all the details. The stock sensor is on the run of the T and my hose for the gauge pressure transducer is on the branch. You can put your sensor right on the branch and skip the hose. I sourced the parts from Summit or Jegs, nost hardware stores don't carry 1/8" pipe fittings. The stock wiring was long enough to reach the sensor connection, no modification necessary.
 

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The only thing I dislike about the location is the oil pressure is at it's lowest ,and I prefer more accurate readings.... That being said ,it's all relative once one learns what's normal for their motor.
 

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Discussion Starter · #27 · (Edited)
So after digging around under the car this weekend, I've decided that both the spots under the car - the port in the block and also the port in the oil filter adapter - are just too close to the header if I moved things around or tried to install my new pressure gauge in either port due to the installed length, unless I found some 90 degree elbows or something. So for now I'll probably just install the pressure gauge sender in the stock pressure sender location at the back of the intake.

The Speedhut sender and wiring harness are super nice, but just end up making a bit of lengthy assembly:
199991
199992


Also thank you Ken for sharing your photo of the 'T' adapter. I'll start searching around for one soon, but not likely to happen before Nats next week anyway.

Tom and others: What do you figure the oil pressure differential is in PSI between the port in the block above the filter and the port up top where the oil pressure stock oil pressure sender lives?
 

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90 degree male/female NPT adapter are easily sourced.
One could install a sender in either/both location to compare readings.
I'm betting the difference is significant....
 

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Personality, I would prefer taking oil pressure off the main galley ( top back ) as it is the most accurate reading , closest to the bearings.
55 pounds at the lower side of the block does mean much if you have 3 at the front of the main oil galley,😏
I am leary of building a christmas tree of fittings and things , especially in an environment like road racing .
Lot of leverage and potential for a fracture.
If a person had a pile of things he needed to mount, I would mount a " manifold" somewhere else with a single line from the engine.

Oil temp in the pan is the closest to oil temp at the bearings you are goint to get.

That said the numbers are somewhat relative.
If you run it it the galley and know what it normaly reads, you will know when it is running hotter
 

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I am seeing examples of brass and aluminum.
I am leary of building a christmas tree of fittings and things , especially in an environment like road racing .
Lot of leverage and potential for a fracture.
If I had to do this I would head to the hydraulic shop for tough steel fittings made for high pressure. They will be tough enough to pass the stress to the engine.

For oil pressure I had good luck using a high quality grease gun hose into the engine, then mounted my sensors firmly to the engine to reduce stress on the fittings. It allowed me to use GM senders on a Olds diesel that did 60,000 miles a year for couple of years. I thought the big pressure sender and switch were too heavy to leave directly connected to the block. Loose hoses that shake are your worst enemy. If everything is fastened down there is less stress.

Accurate temperatures are harder to get as the sensor should be in the oil flow. I have in industrial settings used a oversized "tee" with reducers so the fluid can easily flow around the sender. As pressures and flow get higher the sender becomes less of a obstruction factor.
 

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Discussion Starter · #31 ·
Personality, I would prefer taking oil pressure off the main galley ( top back ) as it is the most accurate reading , closest to the bearings.
55 pounds at the lower side of the block does mean much if you have 3 at the front of the main oil galley,😏
I am leary of building a christmas tree of fittings and things , especially in an environment like road racing .
Lot of leverage and potential for a fracture.
If a person had a pile of things he needed to mount, I would mount a " manifold" somewhere else with a single line from the engine.

Oil temp in the pan is the closest to oil temp at the bearings you are goint to get.

That said the numbers are somewhat relative.
If you run it it the galley and know what it normaly reads, you will know when it is running hotter
Same place as the factory pressure sensor if I'm understanding correctly?
199998


I hear you on having an overcomplicated setup and the lack of reliability that comes with it. FWIW, I think if this gauge proves trustworthy on the first few drives plugged into the factory port at the top rear, I'll just leave it there for now and have a dead oil pressure gauge in the dash cluster.

I'm not gonna have time before I leave for Michigan on Friday morning to make the temp sender in the pan a reality, so I'm gonna keep the sender in the block port above the filter adapter for now. Leave 'well enough' alone!
 

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Yes, in production LT1s that is as close as you are going to get to the main oil galley.
If you are 94-95 remember you have the redundant fuel pump contacts that parallel the relay when there is oil pressure.

They tossed that in 96 like it never happened
 

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Discussion Starter · #33 ·
Yes, in production LT1s that is as close as you are going to get to the main oil galley.
If you are 94-95 remember you have the redundant fuel pump contacts that parallel the relay when there is oil pressure.

They tossed that in 96 like it never happened
I have a '95, but we DID recently swap in a '96 LT1. Pretty sure we switched over the oil pressure sender from my '95 motor as to not have to change anything, as I remember my buddy Glenn mentioning there was something extra they did with the sensor and fuel pump cutoff....

So if I disconnected the stock '95 oil pressure sensor, the car will think there's no oil pressure and not be able to run the fuel pump?
 

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No, contrary to the experts, the fuel pump pressure switch or lack of it ( if the factory relay is operating correctly) can not prevent or stop the fuel pump running.

Without the switch, the system will operate same as a 96.

The switch is parallel to the relay contacts.
Either one closed, the fuel pump runs.

To add , the PCM does not know oil pressure.

You can rip the pan off and the engine keeps running Sure the switch will open but the relay won't as long as it sees an RPM signal.

What guy would see were long crank times if their relay failed.
No pump prime , no pump until , there was oil pressure, closing the switch
 

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Discussion Starter · #35 ·
No, contrary to the experts, the fuel pump pressure switch or lack of it ( if the factory relay is operating correctly) can not prevent or stop the fuel pump running.

Without the switch, the system will operate same as a 96.

The switch is parallel to the relay contacts.
Either one closed, the fuel pump runs.

To add , the PCM does not know oil pressure.

You can rip the pan off and the engine keeps running Sure the switch will open but the relay won't as long as it sees an RPM signal.

What guy would see were long crank times if their relay failed.
No pump prime , no pump until , there was oil pressure, closing the switch
Ok, after poking around on some of the other LT1 forums and reading you answer, I think I'm grasping it a little better.
BUT to be crystal clear, I'm totally fine disconnecting and removing the factory sensor, just leaving the factory plug hang out of the way and using the Speedhut sensor in stock oil pressure sender spot with zero issue, correct?
 

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Simplicity is the main reason behind my preference for mechanical pressure gauge(s)...
 

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Couldn't agree more if you mean that 1/8"nylon crap line included with gauge. 1/4" copper is a vast improvement Better still is AN-04 PTFE teflon/stainless pretty much the same as that type brake hose....
 
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