Factory Gauges... what should they read?

[rackerm]

Just got my rebuilt 351C running and my factory oil gauge reads High and the temp gauge reads Low after idling for about 20 mins. The car is not over heating so the Temp gauge may be fine in spite of the low reading. The High oil reading is worrying me. I just ordered a oil pressure test gauge to get a more precise pressure reading. The Alt gauge is quite a bit left of center, but with the engine idling I checked the Alternator charge at the battery with a Multi-meter and its nearly 14v with nothing else on and high 12v with all the electricals on, so I am not concerned with that gauge.

I should mention the oil pump, water pump and alternator are new units.

I could use a point of reference from those who are familiar with these factory gauges for where typically the factory Oil and Temp gauge needles land when the engine is at normal operating temperatures. Also, what is the typical PSI range for oil pressure? A picture of my gauges below...

Thanks!

 

[73pony]

What oil pump did you install? Standard or high volume? Brand?

 

[jbojo]

Do you have the correct oil pressure sensor installed? Its for a gauge and not the light? What thermostat do you have in it, a 180* or 192* I have a 180 and that is where my temp gauge is too. I have measured the temp with another sensor and it reads 182*, I have 2 water temp sensors installed.

 

[rackerm]

Jason, I installed a Sealed Power Hi Volume oil pump with a heavy-duty ARP shaft. I have the stock (bell shape) oil sending unit. I believe it is the car's original sending unit for the original factory gauges. Could the high volume pump be the reason for the high pressure gauge reading? Should I be concerned that the oil pump shaft could fail as a result? That's one reason I went with the ARP shaft.

John, I have a 180* thermostat, a new Cardone Water Pump and a larger four row radiator for an A/C car. Sounds like my gauge reading is consistent with yours using a 180* thermostat.

Thanks for responding.

.

 

[Pastel Blue]

The only gauge I would have initial concern with based on the photo you supplied is the Alt. Gauge... showing a discharge condition as shown is not normal, so if the system is charging as you note, then the gauge is not reading properly. I would be happy to have high oil pressure... and an apparent cooler water temp reading... Both are within spec based on what is observed on th gauges, and we know these were not the most accurately to begin with... at the very least monitor them and possibly recheck them with a mechanical oil/water gauge(s) to be sure.

 

[73pony]

+1 on Pastel Blue's comment. Also the HV oil pump will result in a higher oil pressure reading but it didn't seem excessive as the gauge was not pegged. Prob would not be a bad idea to check the oil pressure with a mechanical gauge though to get an accurate reading just to be certain.

 

[rackerm]

The only gauge I would have initial concern with based on the photo you supplied is the Alt. Gauge... showing a discharge condition as shown is not normal, so if the system is charging as you note, then the gauge is not reading properly. I would be happy to have high oil pressure... and an apparent cooler water temp reading... Both are within spec based on what is observed on th gauges, and we know these were not the most accurately to begin with... at the very least monitor them and possibly recheck them with a mechanical oil/water gauge(s) to be sure.

Thanks. I assume a normal reading on the Alt gauge is at 12 o'clock give or take a little... correct? Any ideas as to what the problem could be with my Alt gauge?  A ground issue, petronix I and 40k coil, etc? Since it is charging, can Alt gauge be recalibrated?

I have mechanical gauges on order so I will double check the oil and temp shortly. 

Thanks

Rich

 

[Stanglover]

The only gauge I would have initial concern with based on the photo you supplied is the Alt. Gauge... showing a discharge condition as shown is not normal, so if the system is charging as you note, then the gauge is not reading properly. I would be happy to have high oil pressure... and an apparent cooler water temp reading... Both are within spec based on what is observed on th gauges, and we know these were not the most accurately to begin with... at the very least monitor them and possibly recheck them with a mechanical oil/water gauge(s) to be sure.

Thanks. I assume a normal reading on the Alt gauge is at 12 o'clock give or take a little... correct? Any ideas as to what the problem could be with my Alt gauge?  A ground issue, petronix I and 40k coil, etc? Since it is charging, can Alt gauge be recalibrated?

I have mechanical gauges on order so I will double check the oil and temp shortly. 

Thanks

Rich

 Rich, Apparently the alt gauges on these cars are pretty much all shot after a while. Rocketman, RCCI makes a volt meter conversion for about 35 bucks if you want to stay with original gauges.

As you are going to mechanical, did you read my post on that in the Aesthetics section. I am using Bosch gauges as they are similar looking to the originals. Downside is having to drill a big hole through the firewall to get the water temp pick-up through. Other brands might be different, but I could not find suitable looking gauges with an electrical water temp. I am still in the process of constructing the conversion, so I don't yet have it all sorted out, but I'm hoping I can utilize the port on the water pump that is for the vacuum temp switch as I no longer use the distributor retard system. That way I can keep my idiot lights in the circuit. Same goes for the oil. I have an extension fitting on the engine that has a 1/8 NPT port so I can still use the idiot light sensor.

Hope this is helpful

Geoff.

 

[73pony]

The only gauge I would have initial concern with based on the photo you supplied is the Alt. Gauge... showing a discharge condition as shown is not normal, so if the system is charging as you note, then the gauge is not reading properly. I would be happy to have high oil pressure... and an apparent cooler water temp reading... Both are within spec based on what is observed on th gauges, and we know these were not the most accurately to begin with... at the very least monitor them and possibly recheck them with a mechanical oil/water gauge(s) to be sure.

Thanks. I assume a normal reading on the Alt gauge is at 12 o'clock give or take a little... correct? Any ideas as to what the problem could be with my Alt gauge?  A ground issue, petronix I and 40k coil, etc? Since it is charging, can Alt gauge be recalibrated?

I have mechanical gauges on order so I will double check the oil and temp shortly. 

Thanks

Rich

 Rich, Apparently the alt gauges on these cars are pretty much all shot after a while. Rocketman, RCCI makes a volt meter conversion for about 35 bucks if you want to stay with original gauges.

As you are going to mechanical, did you read my post on that in the Aesthetics section. I am using Bosch gauges as they are similar looking to the originals. Downside is having to drill a big hole through the firewall to get the water temp pick-up through. Other brands might be different, but I could not find suitable looking gauges with an electrical water temp. I am still in the process of constructing the conversion, so I don't yet have it all sorted out, but I'm hoping I can utilize the port on the water pump that is for the vacuum temp switch as I no longer use the distributor retard system. That way I can keep my idiot lights in the circuit. Same goes for the oil. I have an extension fitting on the engine that has a 1/8 NPT port so I can still use the idiot light sensor.

Hope this is helpful

Geoff.

Just a suggestion. For accuracy reasons you may want to connect the temp gauge sensor into the original sensor location and the idiot light sensor where the vac switch was located. The location of the vac switch will have mixed coolant temps and may not give a 100% accurate reading all of the time depending on whether the stat is open or closed. I am going the same route. Do you by chance have a pic of the oil pressure fitting you are using??

 

[Stanglover]

Thanks. I assume a normal reading on the Alt gauge is at 12 o'clock give or take a little... correct? Any ideas as to what the problem could be with my Alt gauge?  A ground issue, petronix I and 40k coil, etc? Since it is charging, can Alt gauge be recalibrated?

I have mechanical gauges on order so I will double check the oil and temp shortly. 

Thanks

Rich

 Rich, Apparently the alt gauges on these cars are pretty much all shot after a while. Rocketman, RCCI makes a volt meter conversion for about 35 bucks if you want to stay with original gauges.

As you are going to mechanical, did you read my post on that in the Aesthetics section. I am using Bosch gauges as they are similar looking to the originals. Downside is having to drill a big hole through the firewall to get the water temp pick-up through. Other brands might be different, but I could not find suitable looking gauges with an electrical water temp. I am still in the process of constructing the conversion, so I don't yet have it all sorted out, but I'm hoping I can utilize the port on the water pump that is for the vacuum temp switch as I no longer use the distributor retard system. That way I can keep my idiot lights in the circuit. Same goes for the oil. I have an extension fitting on the engine that has a 1/8 NPT port so I can still use the idiot light sensor.

Hope this is helpful

Geoff.

Just a suggestion. For accuracy reasons you may want to connect the temp gauge sensor into the original sensor location and the idiot light sensor where the vac switch was located. The location of the vac switch will have mixed coolant temps and may not give a 100% accurate reading all of the time depending on whether the stat is open or closed. I am going the same route. Do you by chance have a pic of the oil pressure fitting you are using??

 Jason, good point. The problem might be that because the temp capillary tube may interfere with fan pulley. Going the other route may solve that, but then there may be issues with clearing the alternator. I may have to find a "T" fitting or something, but it ain't going to be easy and have it look okay. I need to do some work on the car rather than just theorizing. I'll take a couple more pics and post them back in my original thread.

WTW, I'm working on that bracket drawing, stay tuned!!

 

[jbojo]

Jason, I installed a Sealed Power Hi Volume oil pump with a heavy-duty ARP shaft. I have the stock (bell shape) oil sending unit. I believe it is the car's original sending unit for the original factory gauges. Could the high volume pump be the reason for the high pressure gauge reading? Should I be concerned that the oil pump shaft could fail as a result? That's one reason I went with the ARP shaft.

John, I have a 180* thermostat, a new Cardone Water Pump and a larger four row radiator for an A/C car. Sounds like my gauge reading is consistent with yours using a 180* thermostat.

Thanks for responding.

.

FWIW, I have a high volume oil pump too and I get about a 3/4 gauge reading for the oil pressure when cold and a little less when the motor is hot.

For cooling I am also using a larger than normal radiator.  Been thinking on going back to a 192* thermostat.

 

[rackerm]

 Rich, Apparently the alt gauges on these cars are pretty much all shot after a while. Rocketman, RCCI makes a volt meter conversion for about 35 bucks if you want to stay with original gauges.

As you are going to mechanical, did you read my post on that in the Aesthetics section. I am using Bosch gauges as they are similar looking to the originals. Downside is having to drill a big hole through the firewall to get the water temp pick-up through. Other brands might be different, but I could not find suitable looking gauges with an electrical water temp. I am still in the process of constructing the conversion, so I don't yet have it all sorted out, but I'm hoping I can utilize the port on the water pump that is for the vacuum temp switch as I no longer use the distributor retard system. That way I can keep my idiot lights in the circuit. Same goes for the oil. I have an extension fitting on the engine that has a 1/8 NPT port so I can still use the idiot light sensor.

Hope this is helpful

Geoff.

Just a suggestion. For accuracy reasons you may want to connect the temp gauge sensor into the original sensor location and the idiot light sensor where the vac switch was located. The location of the vac switch will have mixed coolant temps and may not give a 100% accurate reading all of the time depending on whether the stat is open or closed. I am going the same route. Do you by chance have a pic of the oil pressure fitting you are using??

 Jason, good point. The problem might be that because the temp capillary tube may interfere with fan pulley. Going the other route may solve that, but then there may be issues with clearing the alternator. I may have to find a "T" fitting or something, but it ain't going to be easy and have it look okay. I need to do some work on the car rather than just theorizing. I'll take a couple more pics and post them back in my original thread.

WTW, I'm working on that bracket drawing, stay tuned!!

Thanks Geoff, I did read your post the other day...good stuff! I really liked the mounting bracket work. My plan is to stay with he factory gauges and not go mechanical.  I was just getting the mechanical test gauges to get more precise readings on oil and temp.

I will check out Rocketman's volt meter conversion, sounds like a good option for me.

Very helpful feedback. Thanks All.

 

[Don C]

Going with the voltmeter conversion simplifies things. The ammeter uses a shunt to provide a sample of the current to it. Any corrosion or something else connected to the circuit will cause problems like what you are having with it.

 

[Stanglover]

Just a suggestion. For accuracy reasons you may want to connect the temp gauge sensor into the original sensor location and the idiot light sensor where the vac switch was located. The location of the vac switch will have mixed coolant temps and may not give a 100% accurate reading all of the time depending on whether the stat is open or closed. I am going the same route. Do you by chance have a pic of the oil pressure fitting you are using??

 Jason, good point. The problem might be that because the temp capillary tube may interfere with fan pulley. Going the other route may solve that, but then there may be issues with clearing the alternator. I may have to find a "T" fitting or something, but it ain't going to be easy and have it look okay. I need to do some work on the car rather than just theorizing. I'll take a couple more pics and post them back in my original thread.

WTW, I'm working on that bracket drawing, stay tuned!!

Thanks Geoff, I did read your post the other day...good stuff! I really liked the mounting bracket work. My plan is to stay with he factory gauges and not go mechanical.  I was just getting the mechanical test gauges to get more precise readings on oil and temp.

I will check out Rocketman's volt meter conversion, sounds like a good option for me.

Very helpful feedback. Thanks All.

 Thanks and glad it was somewhat useful.

 I'm continuing my saga on my own post from here on, but if there is something else that comes to mind, I'll chirp in.

Geoff.

 

[midlife]

Your ammeter reads negative when the engine is running? I wonder if you have the two leads reversed. Here's how to tell. Key off, headlights on, door open, brakes on. Which way does the needle swing? Should be negative. If positive, reverse the ammeter leads. If negative, you have a charging or significant wiring problem.

 

[rackerm]

Your ammeter reads negative when the engine is running?  I wonder if you have the two leads reversed.  Here's how to tell.  Key off, headlights on, door open, brakes on.  Which way does the needle swing?  Should be negative.  If positive, reverse the ammeter leads.  If negative, you have a charging or significant wiring problem.

Just tried this test and the gauge stays in the same place.  The more I watch the gauge the more I realize that it is not moving with the key off, key on, engine on or off it seems to make no difference. I was sure it was moving some with the car running and various power draws, but now I am not so sure. I know it never moved to the right of center.  I am going to check the connections and look in to the volt meter conversion.

I appreciate everyone's help and suggestions, I'll certainly update this thread once I have solved the mystery.

Rich

 

[rackerm]

A quick update. I swapped a mechanical oil test gauge in place of the factory gauge and the oil pressure when fast idling cold was 80 psi and at normal operating temp is 69-70 psi. It's a newly rebuilt 351C with a high volume pump and I am using a non-synthetic 10w 30 weight oil with zinc added.

The pressure seems a bit high, but not where I should be alarmed .... or should I be? Appreciate your thoughts here. Thanks

 

[Stanglover]

A quick update. I swapped a mechanical oil test gauge in place of the factory gauge and the oil pressure when fast idling cold was 80 psi and at normal operating temp is 69-70 psi. It's a newly rebuilt 351C with a high volume pump and I am using a non-synthetic 10w 30 weight oil with zinc added.

The pressure seems a bit high, but not where I should be alarmed .... or should I be? Appreciate your thoughts here. Thanks

 Hate to tell you this, but a high volume oil pump is not what you need unless the clearance on the crank etc. have been allowed for and/or your engine is modified. This very problem, my engine builder chose to put one in my 351 C rebuild back in 2012, cause the cam to go out resulting in them doing a warranty rebuild last year. At least, that is what he told me the cause was and put in a standard pump. Oil pressure is 65 psi and I have a good almost stock engine now.

I'm no engine guru and I'm sure some will disagree, just going  by what I have read and have been told.

 

[Don C]

You are correct, Clevelands, unless they have oiling modifications for racing, don't respond well to high volume or high pressure oil pumps. This has been discussed a few times on this forum.