1956 Buick Gauges

[Beemon]

Does anyone have any information on what the Buick gauges should read? I had torn my gauge cluster out to fix some stuck gauges, but now that they're free, I don't think they're reading right. I was told 1955 for the temp gauge goes up to 200 degrees, but when I tested my temp gauge, it was in boiling water and the needle was between N and H. Likewise, under normal driving, the oil gauge won't even go to N. It's always between L and N, and at idle it's in the red. Is the oil pressure gauge between 0-40 or different? Likewise, is the temp gauge from like 140-200 or different?

[JohnD1956]

Going from memory the 56 temp is 203-208 when half red and half green.  No direct info on the oil pressure gauge. 

[Beemon]

John on the oil pressure gauge, next time you're driving, can you tell me where the needle is at about 35mph is? That's about 2000RPM.

[JohnD1956]

Don't need to wait for the next time.  My engine idles just below the middle of the gauge when it is warmed up and two quarts low on oil.  Otherwise it  runs on the high of the gauge. 

[1956322]

Mine at hot idle in gear will be a little below N.. Keep in mind its been between 100 and 110 here and that's after a lot of driving.. As soon as I give it gas it shoots up fast... In cooler temps a lot of driving it'll sit at N in idle.. Cold idle no choke it's halfway between N and pegged usually closer to pegged.. Running castrol full sun 5w 50 and a spin on wix xp filter

[NTX5467]

2000rpm @ 35mph??  That rpm sounds a little high for that road speed!  Shouldn't it be more like 1500rpm at that speed, steady state cruise, in "D"?

 

Water might "boil" at 212 degrees F @ sea level , but a pressurized system can go to about 260 degrees F before it boils over.  With a thermostat temp of 160 degrees F, might the middle line be about 180 degress F?  Most of the newer vehicles, with 195 degree F thermostats have the middle line at about 200-210 degrees F, by observation.

 

I would suspect the oil pressure gauge would be near "N" when it was at the service manual oil pressure spec, with 30 viscosity oil.  The viscosity number is applicable at "operating temperature" in the motor (or 100 degrees C oil temp), which can relate to several things in the engine's inside environment and the particular motor oil, too.

 

When I was in college, I had a friend with an Opel Manta coupe.  When he started it up, the OEM oil gauge stayed "at rest" until after it'd run for a minute or so.  The first time I saw that, I got concerned.  He didn't get excited.  Then, as we drove off, it suddenly sprung to where it should have been.  No noises in the engine, as expected.  Said it was "normal for that car".

 

Is there some calibration adjustment for the oil gauge?  Has to be some way to calibrate it when it was built.

 

NTX5467

[Beemon]

There are tangs to bend, but my lower end gauges were accidentally damaged when I removed the cluster for speedometer repair. They didn't move freely afterwards and I just pulled the whole gauge cluster this last week to diagnose. Basically there are two metal tangs to adjust, one on the needle and one on the spring. Without any way to set them (a custom test box would need to be made to simulate conditions), all I have to go off is other people's cars. Since putting it back in, at normal temp the the temp gauge sits a little below N. I'm also not sure what T-stat is in the car, could be a 160. At idle in gear, the oil pressure gauge sits in the red. When I get on it, it goes up to halfway between L and N and stops. I think my temp gauge may be fine, but the oil pressure gauge seems to be way off.

 

Willis, 2000 RPM during cruise is normal for a Nailhead per my observations. I have had a digital tach in my car for over a year now, and it matches the Sears tach I have in the garage. These readings are consistent with both of my engines.

[NTX5467]

fAs for your temp gauge, you can check it with a non-contact infrared "heat gun" thermometer.  That might be the only way to see what the inside gauge is actually doing!  Check it at 100 degrees F, then when the thermostat opens and temperatures stabilize.  Those two reference points would be enough.

 

Have you used GPS to check the speedometer for speed and distance accuracy?  2000 rpm @ indicated 35mph is still pretty slow for that engine speed, to me.  Indicates a top end speed of only 105mph @6000rpm,, on flat land.  That might be accurate for the deeper gears the Buicks came equipped with OR needed for better performance with the DynaFlow, but it still seems like too much rpm for not enough mph, to me.

 

NTX5467

 

 

Edited July 2, 2017 by NTX5467 (see edit history)

[JohnD1956]

For peace of mind I would install a temporary mechanical oil gauge under the hood and use a test tach to check that oil pressure. The temp sounds fine and it would be interesting to know what the thermostat is for that reading.  When I used to run a 160 thermostat I recall it seemed the temp gauge never went above the N. Now with a 180 it runs just a little above that and will get awful close to the red area at a red light, but doesn't usually go over the line unless it is over 90* ambient temps. 

Edited July 2, 2017 by JohnD1956
fix errors & ommissions from phone keyboarding (see edit history)

[Ben Bruce aka First Born]

I have an oil pressure gauge permanently mounted under the hood on my '50. Must be the hot rodder in me.

 

  Ben

[NTX5467]

In an era when 195 degree F thermostats are "the standard" and all temp gauges seem to be oriented toward the center mark being (as far as I can tell) about 210 degrees F, we're more sensitized in that direction.  On my '77 Camaro, when new, it would stay just below the center mark and that was "Normal" (and expected).  More efficient radiators and cooling fans now seem to much-diminish the "stopped or slow moving" temp creeps, as long as everything is clean and operating correctly.  IF a modern system might regularly register higher than that center mark, with the "red zone" starting at about 260 degrees F (due to additional levels of cooling system pressurization from much earlier times), 260 degrees F is acceptable.  Past that, not too good.  But with the sensitization of the needle movement above the center area, knowing what the areas of the temperature gauge on the earlier cars (with letters rather than numbers) can be more important.

 

When I began to seek to address a "creeping heat" issue on the interstate and increased run time, I sought out the Robert Shaw-style thermostat of 180 degrees F.  That resulted in the temp gauge needle being about 2 needle-width lower position on the gauge, once the thermostat was fully open.  Later, when I installed a water pump with an aftermarket casting and visually more generous coolant passages, the temp needle climbed 1 needle-width higher.  THIS can illustrate the relationship of coolant flow AND related velocity in effective cooling system performance.  Next water pump change, I sought out a factory-casting reman pump and the temp needle went down to prior levels!.  This, at a time when additional coolant flow was touted as "a fix" for increased operating temperatures "under load".

 

As the temperature sending unit (in this case, a "sensor" as it varies voltage to the interior gauge, rather than a "switch" that turns a light on or off), perhaps there can be an inline resistor that can be added to update the resistance levels of the earlier equipment to more of what we're sensitized toward?

 

Back in the middle 1970s, a friend was trying to increase the power from his '64 Galaxie 500 (352 V-8).  It was widely known that a cooler engine resulted in more power output (but with no real knowledge of "how much"), after all, the serious drag racers iced their intake manifolds between rounds.  So he wrote to Edelbrock and inquired as to which thermostat he should use.  The hand-written reply, on a company form, stated that engine wear increased when a thermostat cooler than 160 degrees F was used, with wear reduced with the (then common) 180 degree F thermostat.  The 195 degree F thermostats were used as an integral part of the then-new engine emissions system strategy.

 

As for "engine wear" and longevity, these can be the result of the "warmer" thermostats as (especially in cooler climates) more of the "bad byproducts" of combustion are better cooked out of the motor oil and internal cavities of the engine as it operates.  One reason for the "10 mile/trip" rule of which maintenance schedule one applies to the vehicle, in later times.  Yet, by observation, it really takes more like 20 miles of active driving (not engine operation) to achieve getting the motor oil temperature high enough, long enough to achieve these results . . . with a 180-195 degree F thermostat.

 

Perhaps, at the coming BCA National Meet, there might be enough '55-'56 Buicks there for an enterprising and motivated individual, with fresh batteries in their "heat gun" to shadow this group of owners to discover what the letters on the temp gauge usually mean?  Then post the results so they can be considered and discussed. Maybe even expand it to other eras of vintage Buicks?

 

NTX5467

Edited July 2, 2017 by NTX5467 (see edit history)

[Grimy]

If you think you have problems, 1990s Ford "analog" gauges for both temp and oil are actually "analog idiot lights" because anywhere between stone cold and boiling (for temp) and within range for oil pressure will read (1) slightly below middle of gauge for temp and (2) slightly higher than center for oil--irrespective of actual temp or pressure.