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#2539384 - 08/20/18 11:05 PM Need to add two gauges, water temp and oil pressure
PAULS_340 Offline


Registered: 08/02/05
Posts: 994
Loc: Motown, Mi
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.
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Still looking for LM29H1B415501, '71 Demon 340

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#2539398 - 08/20/18 11:33 PM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
topside Offline
I Live Here

Registered: 01/19/03
Posts: 12625
Loc: So Near, Yet So Far
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.

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#2539405 - 08/21/18 12:01 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
Pacnorthcuda Offline
I Live Here

Registered: 11/19/07
Posts: 19270
Loc: Kirkland, Washington
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.

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#2539407 - 08/21/18 12:20 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
AndyF Offline
Too Many Posts

Registered: 01/20/03
Posts: 24770
Loc: Oregon
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.


Attachments
DSC_2892 (Large).JPG




Edited by AndyF (08/21/18 12:23 AM)

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#2539431 - 08/21/18 03:06 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
skicker Offline
Pro Stock

Registered: 06/09/05
Posts: 4052
Loc: Western Md.
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
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Loving all the tears... bawling

Sorry Doc...

We'll try again in 2 years...up

Edited...Looks like it will be 6 years...biggrin

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#2539453 - 08/21/18 06:55 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
earlymopar Offline
super stock

Registered: 01/30/03
Posts: 859
Loc: Oregon
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

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#2539473 - 08/21/18 08:48 AM Re: Need to add two gauges, water temp and oil pressure [Re: earlymopar]
pushbutton Online   content
pro stock

Registered: 11/15/08
Posts: 1428
Loc: tennessee
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.

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#2539481 - 08/21/18 08:56 AM Re: Need to add two gauges, water temp and oil pressure [Re: Pacnorthcuda]
Supercuda Offline
I Live Here

Registered: 09/04/07
Posts: 13908
Loc: up yours
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
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They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.

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#2539498 - 08/21/18 09:33 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
Magnum Offline
master

Registered: 01/24/03
Posts: 5656
Loc: Hamilton, Ontario Canada
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.
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69 Super Bee, 93 Mustang LX, 04 Allure Super

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#2539510 - 08/21/18 09:53 AM Re: Need to add two gauges, water temp and oil pressure [Re: Magnum]
MarkM Offline
Worthy

Registered: 01/13/05
Posts: 2291
Loc: USA, MI
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.
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'87 Fifth Avenue: 512 low deck roller / 518 / 8.75


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#2539563 - 08/21/18 11:46 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
AndyF Offline
Too Many Posts

Registered: 01/20/03
Posts: 24770
Loc: Oregon
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.

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#2539571 - 08/21/18 11:54 AM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
71birdJ68 Offline
master

Registered: 02/09/12
Posts: 3996
Loc: Morristown Tn.
Marshall insterments has some nice electric gauges, and they also have some that have programable warning lights with a remote if you want.


Edited by 71birdJ68 (08/21/18 11:55 AM)

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#2539576 - 08/21/18 12:00 PM Re: Need to add two gauges, water temp and oil pressure [Re: 71birdJ68]
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 9454
Loc: north of coder
at one time, didn't someone offer an "isolater", similar as used in mechanical fuel gauges, for oil pressure gauges ?
beer

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#2539737 - 08/21/18 05:13 PM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
topside Offline
I Live Here

Registered: 01/19/03
Posts: 12625
Loc: So Near, Yet So Far
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.

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#2539775 - 08/21/18 08:01 PM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
randavis Offline
member

Registered: 02/27/13
Posts: 32
Loc: Missouri
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.

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#2539935 - 08/22/18 07:51 AM Re: Need to add two gauges, water temp and oil pressure [Re: pushbutton]
earlymopar Offline
super stock

Registered: 01/30/03
Posts: 859
Loc: Oregon
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

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#2540040 - 08/22/18 12:55 PM Re: Need to add two gauges, water temp and oil pressure [Re: PAULS_340]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 31552
Loc: Bend,OR USA
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


Edited by Cab_Burge (08/22/18 12:56 PM)
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Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2540184 - 08/22/18 07:22 PM Re: Need to add two gauges, water temp and oil pressure [Re: MarkM]
larrymopar360 Offline
top fuel

Registered: 01/07/11
Posts: 1798
Loc: Central Florida
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.
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Facts are stubborn things.

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#2540322 - 08/23/18 07:33 AM Re: Need to add two gauges, water temp and oil pressure [Re: larrymopar360]
Gavin Offline
top fuel

Registered: 01/24/03
Posts: 1673
Loc: London, England
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.
_________________________
71 Challenger convertible - 414 W2 Stroker.............Car progress can be viewed here!


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#2540354 - 08/23/18 09:09 AM Re: Need to add two gauges, water temp and oil pressure [Re: Gavin]
71birdJ68 Offline
master

Registered: 02/09/12
Posts: 3996
Loc: Morristown Tn.
I agree, they quit using direct mechanical gauges in large airplanes way back in the early thirties.

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