Latest wisdom on mechanical vs electronic senders for gauges?

Dear V-8 Buick instrument gurus,

I'm continuing my attempt to cover all the bases associated with getting my JW assertive engine into my trusty 1965 Special wagon. The current topic of research is the obligatory triplet of gauges to supplement what are so lucidly referred to as: idiot lights. Now I have read Larry70GS's treatise on the topic:

http://www.v8buick.com/showthread.php?197307-Gauges

It talks hopefully about being able to eliminate any mechanical links between the engine compartment and the dashboard. However, 2 years later, locating gauges that are all electronic remains somewhat difficult. I have an additional dashboard real-estate problem so I would prefer to go with gauges which are as small as practical, so that further narrows my choices.

Larry suggests some reasonable precautions to greatly reduce the risk of leaks behind the dashboard if one resorts to mechanical gauges.

What is the current thinking now 2 years since its writing? It is worth the extra effort to get all electronic gauges, or are the mechanical ones fine if you harden the lines connecting to the engine?

Curious minds would like to know!! :idea2:

Cheers, Edouard :beer

 

Edouard, I have had all mechanical gauges on the various engines in my 64 for at least 12 years. While i have had pretty good luck with them however if i had as much tied up in an engine as you have in yours and needed an all new gauge set i would definitely go with the electrical gauges. It seems you have a long history with your wagon and the oil pressure sensing line running from the engine to the gauge does represent a hazard, you wouldn't want to have a fire and lose the wagon due to a failed sensing line would you? The capillary tube for a mechanical temperature sender while not hazardous can be somewhat ugly running from your intake to through the firewall as well.

You should have no problem finding a nice set of auto meter gauges that will fit your needs. They have many different face colors and fonts that should allow you to find one that suits your needs. If for some reason you can't find something that makes you happy check with the street rod supply places I've used classic instruments in the past for my dad's street rods with good sucess.

 

Edouard,
I have a set of each type for my project and am leaning towards the electrical style, they are very easy to install and routing the wiring so that the engine compartment stays clean and sanitary looking is very easy VS the mechanical style. whichever you go with i am sure you will buy a quality product. Bob

 

I ALWAYS liked & used mechanical gauges whenever I could. On mine & customers cars. As far as I'm concerned there are too many glitches & other things with electrical gauges so much so that I normally stay away from them. For the oil pressure use the COPPER line & NOT the nylon line. I use a pice of w/s/wiper hose to cover both the oil & water temp. lines. Less in your face looks being black. And, keep your "Idiot" lights operational as well. A red light that all of a sudden comes on will catch your eye much quicker than always looking at the gauges. Today it's recommended that a"Volt" gauge be used instead of the "Amp" gauge. After a while you will get so used to the mechanical gauges that you will be able to tell by the O/P gauge if your a quart or so low. Also the mecahnical gauges re-act much faster to changes than electric. Even an inexpensive set of mechanical gauges I trust more than electric. They are available as small as 1 1/2" so there will be many places where they can be mounted. Just keep them in a place that's easy to see WITHOUT taking your eyes off the road while driving. For any gauges to do any good YOU HAVE TO ABLE TO SEE THEM AT A GLANCE by just diverting your eyes while still being able to see what's in front of you.
Just my thoughts & experience on the subject.

Tom T.

---------- Post added at 01:06 AM ---------- Previous post was at 12:58 AM ----------

Forgot to mention also. When using mechanical gauges ALWAYS use a coil/curl in the line before going into the dash through the firewall. You must remember that even in normal driving things are FLEXING. This coil/curl prevents the line from breaking as it lets the lines have some give as things are moving. Just as you see the brake lines coming from the master cylinder going to the frame have these coil/curls in them. The w/s/washer tubing coverimg the lines also helps to keep out any engine noises being passed through the lines as they are a DIRECT connection to the engine. So it dampens ANY vibrations that may occur. The old saying "Do it once & do it right" never holds more true & using experience gathered over the years & passing this experience onto others BEFORE they have a problem.

 

I prefer mechanical with braided lines for oil pressure. Have had lots of trouble with sending units leaking or failing. The only electric gauge I have now is fuel pressure and thats because mechanical are a PITA.

 

My electric one has failed. It sticks in the last highest position and is installed in the dash.. That sucks.. As soon as I nail the gas it pegs at about 18 psi and stays there till I turn the key off????

 

I run electrical oil pressure, water temperature and transmission temperature gauges from AutoMeter, they're the Sport Comp line, I could not be happier. Hearing the argumentative talk about responsiveness between electrical and mechanical, I did my own test to compare. My AutoMeter Sport Comp electric oil pressure gauge responds just as quickly as my old AutoMeter Sport Comp mechanical gauge. I'm happy to be running wires where there used to be plumbing.

That being said, I also invested in a warning light on my steering column for oil pressure and now maintain my original coolant temp light in the dash. My gauges sit under the dash and I cannot watch them all the time, and I suffered an engine failure because of the lack of warning lights in the past.

Devon

 

I had the copper line for the mechanical oil pressure gauge fatigue and fail about 3 inches behind the gauge spewing oil all over the place including my brand new shoes. Braided hose for that one as Larry and another reccommended is a definate as far as I'm concerned...

... iffin' you go the mechanical route

 

Ive posted these pics before. My gages are VDO. fully electric sending. No issues in 3 years. View attachment 238904

 

I'm running full sweep electric Autometer Ultra Lite gauges. They tend to cost quite a bit more than their mechanical or short sweep electric counterparts, however it's well worth it in my opinion. And in terms of their accuracy, I've noticed the electric oil pressure gauge responds just as fast as the mechanical gauge it replaced, and the electric water temp gauge actually tends to responds faster than the mechanical gauge it replaced.

 

Ill add that if you can go electric on your speedo, I would -- it'll look smoother during acceleration. Cable driven speedo's tend to bounce around till they are at a steady state of operation. Just my two cents.

 

I've had both type fail on me. Currently I'm all electric and don't have any plans to go back to mechanical oil or temperature gauges in any of my cars. The lower end electric gauges lag a bit, but the higher end ones are fast (and if you use something like a megasquirt to read the sensor, the sampling rate is fast enough to catch each pulse of the oil pump! That's fast!). The cheaper ones are designed to lag so to be more tolerant to noisy electrical systems that old cars are prone too.


IMO, it's highly improbable that ~1/4-1/2 second lag on the oil pressure would make any difference in saving an engine if the pressure suddenly dropped. Your reflexes aren't that quick between observation and reaction even with a fast gauge.


When I get this up and running, I'm planning on porting the electric oil pressure sensor right into it to be right on the dash.

 

I went with the Autometer Sport-Comp II. Selling points for me were the full sweep and temp/ oil pressure warning light (adjustable) included on the meters. Having the warning light built in
allows me not to run the "T" fitting and extra pieces that may leak in order to keep the dummy light.

Not having a light indicator wasn't an option.

I too was worried about the accuracy of electric vs mechanical and found the autometer electric, cheap autozone mechanical and Snap-On mechanical to all be within 1 psi of each other at idle and the Snap-On vs Autometer to be dead on at 2000RPM.

Didn't think to check reaction time.

I'm happy with my electrics.

 

Thanks for all the good advice!! (Re: mechanical vs electronic senders for gauges?)

Dear V-8 Buick instrumentation gurus,

Thanks for all the helpful replies to my question!! :TU:

I've been trying to come up with a scheme based on all these good ideas. However, there wasn't enough time today to really come up with something solid . . . . .

Therefore as I keep saying . . . . stay tuned!!

Cheers, Edouard :beer