Oil pressure gauge questions

[The Warden]

Hello (again)

First, I'm trying to start a debate in general...if you had a choice either way, would you prefer a straight-mechanical gauge or an electric gauge for oil pressure (and water temperature)?

It seems to me that both have their ups and downs; with a mechanical gauge, you have oil coming into the cab if the line breaks...but with an electrical gauge, it's functionality depends on the electrical system and on an electrically-operated sending unit.

Second, if you had a choice, where would you put an oil pressure sending unit on an IDI, assuming that the stock gauge is permanently inoperative? I've heard of three options...either put the sending unit where the factory sender was located, put the sending unit in a plug in the block near the oil filter, or putting it in a T-fitting with the line going to a turbo (if a turbo'ed engine).

I don't especially want the sender where the factory one was located; it's too close to the turbo for my confort level (in addiiton to being nearly impossible to get to), but if it truly is the place where you're going to get the best reading, I'll figure a way around it being close to the turbo...

Any thoughts would be appreciated, and a civil debate would actually be desired. Thanks!

Oh yeah, one more thing...if a mechanical oil pressure gauge is failing, does it "generally" fail low or high? I haven't been able to do an active comparison, but I think my oil pressure gauge is sometimes reading lower than the actual pressure...

Thanks again

 

[ericboutin]

Well it's just my .02 but with all the horror stories about mechanical gauges spewing oil all over dashes i don't think I could ever go that route!?!

 

[Diezel_Cowboy]

I would have to say i would prefer a electronic gage setup as well. Nothing wrong with an electric signal as opposed to the oil itself coming into the cab.
I just replace my sending unit this fall, my gage was reading low and i suspected that it was the sending unit. It only cost $20 for the sending unit but while installing it i over tightened it and broke the cast T-piece where it mounts above the turbo!
This cast piece supplies oil to the turbo and with it broken the truck was inoperable! I was pissed! So i bought a new cast piece for $50 dollars and installed it being very, very careful not to over tighten it the second time. When i called around to get the cast T-piece there were only 3 of them in the entire state of Ohio,...........now there are only 2! So i would recommend being very careful when replacing one of these oil pressure sending units on a factory turbo IDI!

 

[hoodshauler]

I have never had a problem with the mechanical type, I have always had them in every vehicle i own but I also replace my tubing about every two years also.

 

[Carl_F350]

I also prefer the electrical gauge. I actually just replaced the factory oil sending "switch" on my 94' factory turbo with a real oil pressure sending unit. Then you have to solder a jumper on a 20 ohm resistor on your gauge cluster. Now my oil pressure gauge actually moves from "n" at idle to "m" on the NORMAL gauge when I'm on the go. Everything works fine no problems.

I found the instructions on that other site we do not speak of.

 

[F350camper]

Originally posted by Carl_F350
I also prefer the electrical gauge. I actually just replaced the factory oil sending "switch" on my 94' factory turbo with a real oil pressure sending unit. Then you have to solder a jumper on a 20 ohm resistor on your gauge cluster. Now my oil pressure gauge actually moves from "n" at idle to "m" on the NORMAL gauge when I'm on the go. Everything works fine no problems.

I found the instructions on that other site we do not speak of.

Did the same thing, and found the instructions on the same site.

I took it one step further and calibrated the gauge by hooking the new sender up to my compressor. Then I made tick marks on my gauge face at 20, 40 and 60 psi. Works great!

 

[The Warden]

Must be nice having a '92+ truck that you can actually do that mod to I don't know if '87-'91 trucks can be modded like that, and I know for sure that '80-'86 trucks can't.

That said, sounds like the electrical gauge is winning...any further thoughts on where to put the sender? I've got a turbo now, but my truck was originally n/a (as were all 6.9l's), FWIW...

 

[budtoh3zo]

I went mechanical in my truck and in all my vhicals i have, Excet the YJ because it had a good stock one but it just took a dump. Mechanical all the way.

 

[Tristan]

Tim,
My Electrical guage is going to be read off of the plug down by the oil filter. I haven't decided if I will tee off of my turbo feed line or use the other plug up in front of the filter. I want to keep my factory one working for looks, well okay maybe more fro ***** and giggles about how inaccurate it is.

 

[jdkline]

For me its mechanical gauges. Cheaper and very accurate. I've heard yours and a couple other horror stories oin the other diesel site but not enough to make me think they area disaster waiting to happen. As for mounting location, I was lucky enough that the former owner was a TDS member and mechanically inclined. The factoy gauge and mechanical gauge now both work.

 

[argve]

Either way you go (mech/elect) you can't really go wrong. But with a mechanical you can take the chance of shooting hot oil in the cab (been there, done that).

now with the electrical, you have to worry about good clean connections. But typically once you put them on you won't touch them again for many years unless you got a poor connection from the get go. Same can be said for a mechanical but vibration plays a big part on the mechanical lines (nice smooth vibration free trucks we have). Tthe electrical is easier to install, just string a wire and have no worries.

Really when you break it down accuracy wise they both will fall into about the same ball park. Now price wise - mech means cheaper. Most mech gauges give you a 180° sweep of the needle, now most off the shelf elect give you 90° sweep. But you can get 180° sweep elect gauges. Just check out ISSPRO EV line of gauges (for example)- highly accurate (4-20ma), long sweep, but price is higher (but there is a reason for that).

Me I will choose an electrical gauge anyday of the week because
1. It can't leak on my dash
2. easy to install.
3. see number 1.
4. I just like electrical stuff.

 

[kennyd]

That said, sounds like the electrical gauge is winning...any further thoughts on where to put the sender? I've got a turbo now, but my truck was originally n/a (as were all 6.9l's), FWIW... [/B]

I tried the "T" in the turbo line like you suggested in your first post, But I got VERY low readings, seems that the turbo is a high flow device, so the pressure was reading low.
So on to plan B:
I used a 18" stainless hose from the port by the oil filter to the sender mounted on the firewall, I think the sender mounted there will add to its life , as apossed to being mounted directly to the engine.

Kenny D.

 

[F350camper]

Originally posted by kennyd

I used a 18" stainless hose from the port by the oil filter to the sender mounted on the firewall, I think the sender mounted there will add to its life , as apossed to being mounted directly to the engine.

Kenny D.

That's a good idea. Should make it last a long time.

 

[The Warden]

Originally posted by kennyd
I think the sender mounted there will add to its life , as apossed to being mounted directly to the engine.

Why do you think remote-mounting the sender will increase its life? I'm guessing either heat or vibration; just wondering.

That might actually answer a few issues, particularly how to run the sending unit wire and make it look clean.

Interesting concept...where did you get the stainless hose from? I assume it's a braided flexible hose... Do you have any pictures?

Thanks!

 

[argve]

i used braided stainless on The E. I found that vibration and heat were both killers of the ISSPRO EV 1st. Gen oil pressure senders (single wiper design). I ended up moving the sender to the drivers side (zipped tied to the master cylinder) - ok it was cheesy but it worked. Actually I moved both the stock one and the ISSPRO one over there, just ran the line up to a tee and wa-lla!