Hi guys, I’m ready to order some gauges but I’m not sure if I should get mechanical or electrical ones! 25 years ago I had my oil pressure gauge pop and spray under my dash bad so I’m a lil nervous! What do you guys think?? What kind should I get?? This is the brand I’m buying



thank you

 

I have a GlowShift fuel pressure gauge. It has an analog sweep on it and uses an electric sender. It works great. It's the first gauge I bought that wasn't an AutoMeter. The coolant temperature sensor and pyrometer I have in my 86 Ford F250 use an electric sender too. The vacuum gauge I have in my truck has a vacuum hose running to the engine.

 

I'm not familiar with that brand. I've never had a line break in decades, I like mechanical gauges.

 

I'd go mechanical for at least the water temp since it's not invasive (i.e. I'd be much more worried about a mechanical oil gauge line leaking into the passenger compartment if it loosened or ruptured).

Electrical for oil pressure, trans temp, volts, etc.

 

I actually usually go the other way - mechanical for the oil pressure and electric for water temp. The sending unit for the mechanical temp gauge can be difficult to route through the firewall, and the fastener at the engine end requires a larger than normal hole in the firewall. I've never had an oil line leak, and I've used plastic as well as copper. More importantly, I try to get gauges that are a full 270 deg sweep as opposed to the 90 deg or less sweep typically used on electric gauges. AutoMeter does make a 270 deg sweep electric gauge line, however.

 

The factory-installed oil pressure gauge in my 1970 Corvette is mechanical. It has a plastic line coming into the passenger compartment. It has never leaked; perhaps because no one has ever tried to "improve" it.

 

Mechanical gauges are subject to leaks or damage to the thermocouple between temp sensor and gauge. Oil pressure can leak at either end (sensor or gauge). Plastic hose can burn through.

Wires are easier to route from sensors to the gauges. They also don't work unless the key is "on". Oil pressure line and temp sensor thermocouples work continuously without electrical power.
I think the temp gauge and oil pressure line is "buffered" a bit due the length and speed it transmits to the gauge. I think electric provides a quicker reaction. I have used both. I would use electrical because its easier to install.

 

Modern electrical gauges are pretty darn reliable as long as you stay with a name brand. For a strictly street vehicle that's what I would probably use. I like Autometer personally.

 

Just to clarify, mechanical temp gauges don't use a thermocouple. they use a capillary tube that contains a fluid that expands with temperature. As this fluid expands, it attempts to straighten the curved bourdon tube in the gauge itself, the end of which is linked to the needle, causing it to move. Mechanical oil pressure gauges work the same way, only it's the oil pressure itself that moves the bourdon tube. As I said above, I care less about how the gauge senses and more about the amount of travel in the gauge. More travel (270 deg vs 90 deg, for example) means more accuracy.

 

Joe P, you are likely correct.

 

It’s a matter of preference.

I remember when I first put gauges in my car (almost 30 years ago) nobody made electric with 270 degrees of needle movement. I never cared for the short resolution, so I went mechanical. I did use #3 AN braided hose on the oil pressure, much more durable and zero leaks.

About 10 years ago I replaced all the gauges with electric Autometer. I really like the programmable warning light, a bright LED will get your attention when something bad happens.

 

Thank you guys!!! I went with Autometer full sweep mechanical oil pressure, full sweep electrical temp I’ll order the voltage gauge later, dang gauges are expensive 😂😂 thanks again

 

Smart move on the electric temp. Those bulbs are a pain to fit through the firewall. Use AN line for the oil pressure to avoid poppage. -4 or -3 is good, and you can get prefab Allstar lines pretty cheap.

 

AN lines for an oil pressure gauge are really overkill. If you're worried about the plastic line, just get the copper instead.

 

I also used a braided AN line for a recent mechanical oil pressure gauge install. Looks much better (to me) in the engine bay than the plastic or copper line.

Pro tip: test the temp sensor BEFORE you install it (ask me how I know). You can do this easily by placing the tip of the sensor into a pot of water and watching resolution as the water reaches a boil.

 

AN lines for the oil pressure. The 5ft -4AN Summit brand one works really good. Wrap in a little loom and you don't even notice it.

 

yes sir that’s what I ordered

 

Copper kinks easily and isn't flexible. We all start somewhere. LOL

 

Do it right the first time.

https://www.summitracing.com/parts/SUM-G2959

 

We'll have to disagree on that. So long as one is not ham-fisted, the tubing doesn't kink. And unless you have a broken motor mount, the copper doesn't move that much. A rubber grommet at the firewall provides more than enough motion accommodation. Again, do what you gotta do, but braided AN lines are just rubber on the inside (unless you spring for the teflon versions). I've had the rubber deteriorate, causing the liquid to spray through the braid. That was fuel on a running engine. And I've matured to the point that I don't want or need the bling anymore. I'd rather hide all the lines and wiring.

 

I have to agree with Joe P. I think steel lines are more likely to kink than copper.

The problem with "metal" lines is if you want to remove a head or intake manifold. It takes more time to disconnect the line and gently bend it out of the way. An electric gauge can be unplugged quickly and taped out of the way. Re-connection is a breeze. The electric gauge or sending unit are easy "plug and play" items.

 

I ran copper for a long time. I'm not saying it won't work 1000x better than plastic.

 

Got this form Sensor Connection, temp gage, didn't want anything hanging under dash, and this fit well in the space, used a 2 sided 3M tape dot to adhere to upper dash panel, small hole through the side of dash panel for wire, has programable alarm, and other bells and whistles, reads ambient temp of outside/engine in this pic!

Temp gage mock up

Temp gage

 

i had a plastic oil line leak under the hood when my voltage regulator shorted inside and melted the wire to my alternator which was all neatly wrapped together along the valve cover, i noticed a large smoke cloud behind me and pulled over. the intake manifold was full of oil and it poured off the back onto the exhaust when i took off. what a mess

 

And the other way to look at that is that without the oil smoke, you probably wouldn't have known about the problem until the fire started under the hood.

 

true, i never notice my little altmeter at all

 

You look at it constantly while you drive?

 

Another good reason to NOT use the plastic lines. Its hard to make the ferrule seal on a soft plastic line that keeps collapsing.

You're very lucky you caught it before you pumped the oil pan dry and burned up the engine bearings.

 

I do. One of my friends who was riding in the back seat noted that I looked at the gauges on a regular interval. He said I cycled from looking forward for a few minutes, then a quick look in the rear view mirror, a quick look at the gauges, and repeat for the entire road trip.

 

Ammeters are a choke in the charging system because they're usually in series between the alternator and battery. Volts will tell you enough, 13.8-14.4 nominal.