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Need to add two gauges, water temp and oil pressure

Posted By: PAULS_340

Need to add two gauges, water temp and oil pressure - 08/21/18 05:05 AM

Need to add electric water temp and oil pressure gauges. Is there a benefit to mechanical oil pressure over electric? Friend has NOS Mopar Performance set. I thought I was going to get electric oil pressure. What say you? Thanks.
Posted By: topside

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 05:33 AM

I prefer mechanical for both. I don't want a possibility of misinterpretation, just what's actually happening right now.
Only electric gauge in my racecar is a digital voltmeter, because it takes basically no power to operate.
Posted By: Pacnorthcuda

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 06:01 AM

OK,
Mechanicals have always been thought of as more accurate, simpler in operation, and usually meant "full sweep" ---270 degrees vs about 120.

There are exceptions. As far as brands, AutoMeter makes great value-for-the-dollar stuff.
Posted By: AndyF

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 06:20 AM

I don't think there is a problem these days with electric gauges. A mechanical water temp gauge is really a hassle. A mechanical oil pressure gauge isn't as bad but you're still bringing hot oil into the passenger compartment. I still have a mechanical vacuum gauge and oil pressure gauge in my car but next time I redo the console I'll switch everything over to electrical.

In the current console I have a tach in the center and then oil pressure, vacuum, water temp and AFR in the corners.

Attached picture DSC_2892 (Large).JPG
Posted By: skicker

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 09:06 AM

Be sure to ground them back to the motor and not to the dash frame...
DAMHIK...
I can tell you for a fact that if you crank up the stereo it will peg the gauges... runaway
Posted By: earlymopar

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 12:55 PM

The only problem I see with a mechanical water temp gauge is the size of the sending unit which requires a corresponding large hole in the firewall.

Mechanical oil pressure gauges do not bring hot oil into the car interior. In any I have had, the oil runs a couple of inches into the tube (still in the engine bay) and the rest of the tube is pressurized air which is what drives the gauge.

- EM
Posted By: pushbutton

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 02:48 PM

Originally Posted By earlymopar
The only problem I see with a mechanical water temp gauge is the size of the sending unit which requires a corresponding large hole in the firewall.

Mechanical oil pressure gauges do not bring hot oil into the car interior. In any I have had, the oil runs a couple of inches into the tube (still in the engine bay) and the rest of the tube is pressurized air which is what drives the gauge.

- EM


Let the line break at the gauge and see what happens.
Posted By: Supercuda

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 02:56 PM

Originally Posted By Pacnorthcuda
OK,
Mechanicals have always been thought of as more accurate, simpler in operation, and usually meant "full sweep" ---270 degrees vs about 120.


About 20 years ago that was true. Not today
Posted By: Magnum

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 03:33 PM

I understand ALL the advantages of mechanical. Had them in the past. We can all pull it the "it's been fine for me" but to bring pressurized oil in the interior is a poor idea.
Posted By: MarkZ

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 03:53 PM

Originally Posted By Magnum
I understand ALL the advantages of mechanical. Had them in the past. We can all pull it the "it's been fine for me" but to bring pressurized oil in the interior is a poor idea.


Had a line break on me a long time ago. Didn't have any tools on me with the exception of Leatherman I kept on my belt. Ended up driving twenty minutes home with one hand under the dash pinching the line off with those pliers. Never did get the stains out of the carpet and had to replace it later on. Been electric Autometer gauges ever since.
Posted By: AndyF

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 05:46 PM

I use #3 braided steel lines for the oil pressure line but I'd rather not have it in the interior of the car if I can avoid it. So next time I update the gauge panel I'll switch to electric. I doubt there is an accuracy issue and the electrical gauges are easier to deal with.
Posted By: 71birdJ68

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 05:54 PM

Marshall insterments has some nice electric gauges, and they also have some that have programable warning lights with a remote if you want.
Posted By: moparx

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 06:00 PM

at one time, didn't someone offer an "isolater", similar as used in mechanical fuel gauges, for oil pressure gauges ?
beer
Posted By: topside

Re: Need to add two gauges, water temp and oil pressure - 08/21/18 11:13 PM

I should mention that if one uses a mechanical oil pressure gauge, use a metal line instead of the cheap plastic one that's usually supplied. Or use a braided stainless line, but that stuff's abrasive to whatever it might rub against.
I like Moparx's suggestion of an isolator, though I don't know how well it'd work at oil pressure #s.
I haven't had one gauge leak in 30 years. Only one that did was the plastic crap I used one time before that; it was pinched at the gauge fitting.
As for feeding the water temp sensor through the firewall, I've always found a hole already there somewhere so I didn't have to break out the drill.
Posted By: randavis

Re: Need to add two gauges, water temp and oil pressure - 08/22/18 02:01 AM

I use a mechanical oil pressure gauge. I plumbed it with two stainless braided lines and use a bulkhead fitting in the firewall. I also use a tee in the block and keep the sending unit for the light.
Posted By: earlymopar

Re: Need to add two gauges, water temp and oil pressure - 08/22/18 01:51 PM

Well duh. Of course that would happen. But there is nothing in the car until you open the end of the tube. The same thing is true with your heater hose!

- EM
Posted By: Cab_Burge

Re: Need to add two gauges, water temp and oil pressure - 08/22/18 06:55 PM

I use to use the mechanical race gauges only, but not since I had a Autometer water temps read 40 F hotter than the water temps where in the upper radiator hose water with the electric water pump circulating the water shock The gauge was reading 145F and I stuck my finger into the radiator and it was right at body temperatures, 98.F according to a high dollar heating and air conditioning pocket thermometer shruggy
I've seen more than one mechanical temp. gauge read bad since then with other good brands puke
It is your choice, the new electric digital gauges are very accurate according to other older mechanical gauges as well as new analog electric gauges used on the same motor at the same time work scope
Posted By: larrymopar360

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 01:22 AM

Originally Posted By MarkM
Originally Posted By Magnum
I understand ALL the advantages of mechanical. Had them in the past. We can all pull it the "it's been fine for me" but to bring pressurized oil in the interior is a poor idea.


Had a line break on me a long time ago. Didn't have any tools on me with the exception of Leatherman I kept on my belt. Ended up driving twenty minutes home with one hand under the dash pinching the line off with those pliers. Never did get the stains out of the carpet and had to replace it later on. Been electric Autometer gauges ever since.
I had a problem with the brass fitting, but it was my own fault. I hadn't connected the brass ferrule properly. I didn't have any tools so I was driving back home with the line folded but hot oil still seeping. But again, my fault. After that, never had an issue with the gauge.
Posted By: Gavin

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 01:33 PM

Honestly, it's a myth that mechanical are somehow inherently more accurate than electrical. In both cases you are taking a physical property like pressure of temperature and converting it to a gauge needle position. The accuracy is only as good as the measurement and the conversion. Every modern car uses electrical/electronic gauges for everything, including the speedo which has legal requirements for accuracy. So the accuracy of your gauge is down to the quality of the design & construction more so than the technology. Also, if we take a step backwards, how accurate do we need most gauges to be anyway? Realistically if they are within 5% of reality that's enough in most applications, and from a design/manufacturing perspective that is not really challenging.
In this day and age I wouldn't even consider a mechanical gauge unless there was some nostalgic appeal or you already had them for free.
Posted By: 71birdJ68

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 03:09 PM

I agree, they quit using direct mechanical gauges in large airplanes way back in the early thirties.
Posted By: Supercuda

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 03:31 PM

Originally Posted By 71birdJ68
I agree, they quit using direct mechanical gauges in large airplanes way back in the early thirties.


Pretty sure no one is selling aircraft quality gauges as hot rod items. Big difference in certifications there.
Posted By: 71birdJ68

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 06:09 PM

Just saying, why are we still using steam gauges when almost everything else has stopped using them and a long time ago.
Posted By: Supercuda

Re: Need to add two gauges, water temp and oil pressure - 08/23/18 07:05 PM

Originally Posted By 71birdJ68
Just saying, why are we still using steam gauges when almost everything else has stopped using them and a long time ago.


Because they are adequate unto the job at hand. No need for a $300 stepper motor driven oil pressure gauge when a $15 mechanical one is more than adequate. You aren't going to fall out of the sky and kill hundreds of people if your gauges are "old fashioned" nor do you need to spend hundreds of extra dollars on your gauges.
Posted By: Magnum

Re: Need to add two gauges, water temp and oil pressure - 08/26/18 03:53 PM

I've already contributed to this thread but I also agree with a reply from Gavin.

This is not an engine laboratory, accuracy in a gauge is over rated. If my oil pressure shows the difference between 0, low, med and I'm still cold, take it easy. It's good enough.

Think of what is going on under the hood of a Hellcat. Would installing a nylon hose from the engines oil gallery to a mechanical gauge inside the car be necessary? NO
Posted By: fourgearsavoy

Re: Need to add two gauges, water temp and oil pressure - 08/26/18 07:34 PM

Well like has been said already it all depends on the quality of the gauges and senders. I still have an old set of Stewart Warner mechanical gauges from 1977 in my Savoy and I trust them and maybe that's why I still have them in the last 6 cars I've owned.
If I were going replace them it would be VDO gauges senders twocents
Gus beer
Posted By: 71birdJ68

Re: Need to add two gauges, water temp and oil pressure - 08/26/18 08:14 PM

My point was so many people think that if you don't have a mechanical gauge, then you might as well not have anything.
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