Mech. or Electric gauges????

[Tom Tom Turbo]

I've decided on Ultra-Lites for the ol WH1 but should I go for electrical or mechanical gauges???? I'm for sure getting oil psi, water temp. and boost. Possibly tranny temp or volts too. Which works better and why????? I had a bad experience with a mechanical oil psi in my Mustang........oil on leather is bad...... But I would like you opinions too!

 

[John84GN]

From my limited knowledge...I would recommend an electric oil press. guage, for that VERY reason!...you don't want 40 psi. of oil going in your TR!!!

I personally prefer:

Elec oil press
Mechanical water temp (I think it's more accurate)
Mech Boost (Definately more accurate)
Elec Tranny temp (for the same reason as the elec oil...DOH!)
and of course...elec volt

Don't know if you have a Knock guage, but if you get the white faced one from caspers, or cottons...it matches PERFECTLY with the "phantom" guages (thats what I've got )

anyway...my $.02

 

[FJM568]

I would actually go with mechanical...They react faster to changes than the electrical and I think they are more accurate...As for the mechanical oil pressure guage, I personally have had a problem with the electric sender for the oil pressure gauge springing a leak and spewing oil all over under the hood...What you need to do on the mechanical oil pressure gauge is buy the stainless braided line that threads onto the fittings and don't even think about using the compression fittings and the 1/8" plastic tubing...

 

[tom h]

For any critical guage (boost, oil) I prefer "full sweep" guages -- and those are usually mechanical. While less critical I also prefer a full sweep water temp guage -- again, usually mechanical.

Leakage should not be a problems with properly installed SS overbraided teflon tubing.

Fuel/gas is an exception -- NEVER route into passenger compartment -- either hood mount a mech guage or pay the extra $ for an elec guage.

 

[salvageV6]

Or use an isloator for the mech. gauge.

 

[Carolinaturbot6]

Posted by FJM568: "What you need to do on the mechanical oil pressure gauge is buy the stainless braided line that threads onto the fittings and don't even think about using the compression fittings and the 1/8" plastic tubing..."

Although I think using braided line is certainly a good idea, & could help prevent an accident, I don't think AutoMeter would use that plastic tubing unless it was tested thoroughly. I actually was leary of using it at first also, but a few locals & a few more TB members changed my thinking. As many of those gauges that are sold & used every year, if the tubing wasn't safe, I doubt AutoMeter would continue using it.

On that note...I still would like to know exactly what line & fittings you used? Sizes would be nice. It would be good to have in the archives here as well.

Thanks

 

[FJM568]

Well, let's just say that I had a really bad experience with the 1/8" plastic tubing...It popped off of the block fitting running down the road at 60 mph and I lost 3 qts of oil in about 5 secs that it took to see the smoke pouring out the back of the car, looking down at the gauge, and turning the motor off...

What I ended up using is the stainless braided line that I bought at a local speed shop...The brand is called Longacre...Part # LON 4505 (60" line)...It was about $27...

Summit carries the Autometer brand...part# ATM-3228 (6' line) for about $50...It is -4 AN braided stainless line with 3/16" id fittings...

I'd imagine that Summit also carries their own brand of lines as well for a little bit less than that...That is what I would use...

Also, as someone had suggested, if you do buy mechanical gauges, get the ones where the needle has a 270* sweep...They are easier to read but are a little more expensive than the ones with the 90* sweep of the needle...

 

[tom h]

-03 stainless overbraided teflon hose with -3AN ends is also quite manageable, and is what I used on my mech oil gauage.

from my Aeroquip catalog, this size hose is 0.25" outside diameter. 3AN-to-NPT adapter fittings in 1/8" NPT male or female, straight & elbow, are readily available. With another NPT reducer bushing, you can adapt to 1/4, 3/8, 1/2 NPT or whatever is needed at the engine.

the other style hoses are going to be too big.
eg, smallest size Aeroquip AQP racing hose is -04, with a whopping 0.45" OD -- will never fit behind a guage.

Routing the stainless braided tubing thru corrugated plastic tubing (same type used on wiring), or wrapping it with 3M Black electrical tape, will keep the underhood looking more stock (if that's what you want). It also keeps the SS braid from rubbing off paint or gradually cutting thru other stuff under vibration -- the SS braid is like a file.

 

[TurboDave]

If I had my druthers, it would be mechancal!! Electrical gauges are totally susceptable to voltage variances, and as such are horribly inaccurate!! At least my VDO's are!!


I have my VDO water temp gauge installed in the front of the intake just on the other side of the thermostat from the ECM's sensor.

While the ECM is showing 200 for example, the VDO is showing 260

I tend to think the ECM's sensor is accurate since the car has never overheated or even come close. I think if the water temp was really 260 it would be overheating? right?
I'm sick and tired of this VDO junk anyway.

You should see the temp gauge jump around when the fan turns on and off and pulls the system voltage down only one volt!

 

[Carolinaturbot6]

Thanks for the size info Jim & tom h.

Jim, I can certainly see why you don't like the plastic tubing.

You didn't make me feel any better about using it on my car though.

AutoMeter sent me a 12ft. length of tubing with mine. I didn't realize it until I went to hook it up, along with some other gauges about a week ago. I went ahead & used it. I just coiled the excess up & made dang sure it didn't kink at all. I didn't know to specify the length. Why the heck would any car need 12ft. of tubing anyway?

I learn something new everyday, sometimes the hard way.

I may eventually get a braided line...just to be on the safe side.

 

[OneQuikV6]

FYI, while I'd prefer to use the braided stuff, I ended up plumbing my mechanical AM Pro Comp Oil Pressure guage with the 1/8" copper tubing with associated compression fittings like the plastic tubing. In all my years of doing this on various cars, I've never had a problem. the plastic stuff WILL break if kinked or even bent too many times. The copper stuff is a bit fragile too, but a MUCHO big improvement over the plastic stuff.

 

[Devil Car]

12 ft of tubing= lucky guy

You're lucky, my oil pressure gauge only came with about 6 ft of tubing. It was a tight stretch, but luckily the gauge was already coming from the passenger side.

 

[FJM568]

While I have never used copper tubing, it will work harden over time from vibrations and heat and will eventually stress crack...Now, how long that would take I don't have any idea...

One thing to do if you do use copper tubing, is to leave it maybe a foot longer than needed and coil the excess up like they do on the brake lines coming off of the master cylinder to allow for some movement and flexing...

 

[Gokou]

The copper tube going to the oil gauge in my '65 Corvette is still going strong, even after 37 years. There is excess coiled in the engine compartment.

As far as the nylon tubing goes: I ran it for years on my Chevelle. The common mistake people make with nylon tube and brass compression fittings is that most people overtighten it. The brass compression fitting will cut through that nylon when you go too tight, and then it's only a matter of time before it breaks off. You don't have to go more than snug to get it to seal, even if you want to keep tightening.

Still, after an incident with the nylon tube letting go last year, I ran -4AN braided to the oil gauge in my Chevelle, which lead to another problem. My gauge is now LOUD! I can literally hear the noise of the gears in the oil pump through the line. The -4AN has such a large volume of oil in it that it transmits the noise of the oil pump far more than the 1/8" nylon tube did. It's actually pretty darn noisy in the car. Still, I don't have to worry about that nylon breaking again... But I wish I could silence the gauge. Any suggestions?

 

[salvageV6]

I used a combination of copper where my fitting is in the very hot turbo area and had to put a coupler in to the plastic line near the coil pack.

Best of both lines.

Plastic used to snap off after the heat got to it when you just looked at it.

Autometer gauges mechanical are very good. Don't overbend the capillary tube lines however.

Been there done that....