Need help understanding thermal dynamics...

[topchop]

59AB Motor, fresh rebuild.
About 400 miles, runs good.
I have the original temp unit in one of the holes in the driver side head, with an aftermarket (SunPro) gage in the other hole on the same head. 180 degree thermostats, which have been tested prior to installation. Heater hose connected to hole on the passenger side head, with a plug in the remaining hole next to the radiator hose neck. (see pics)

At running temperature, the dash gage reads 7/8 hot, and the new temp gage reads 180 degrees. Great.

Here is my question:
Just bought a laser infrared thermometer.
Driver side head reads 180 degrees. The passenger head reads 25 to 30 degrees cooler. Checked it many times with motor running and a couple of minutes after shutdown. I have ordered another SunPro gage for the other side, but interested if this is normal. Does the heater hose have that much impact on head temp?

 

[JSeery]

The flathead engines run different side to side, it is like two independent systems. 25 to 30 degrees is a lot, but not unheard of. The heater core is going to act like an additional radiator, but you might see the same difference with the heater hose pluged. If you have a shut off valve might be an interesting experiment.

 

[ford38v8]

That much of a difference in temperature is not right. The obvious difference of the heater on the passenger side may cause a small difference, but the major difference is something else. I'd first confirm that all cylinders are firing, because that's way too cold for a fully warmed up engine. Perhaps the exact positioning of the infrared device is different from side to side?

 

[PeterC]

My 59AB runs 10 degrees difference - drivers side is 180 / passenger side is 190. I've always asked the question and never got a fact based logical answer other than that is the way flathead Fords are.

 

[uncle max]

My 59AB runs 10 degrees difference - drivers side is 180 / passenger side is 190. I've always asked the question and never got a fact based logical answer other than that is the way flathead Fords are.

The oil splash always accounts for one side running a bit cooler.

 

[topchop]

Re: ford38v8 above,
Pulled plugs on passenger side and looks like they are firing.

 

[aandtman]

I have a stock 37, duel exhaust, no crossover. Duel SW temp guages, no thermostats. Had same problem with 25-35 temp differences. I have a gas analizer, so I pulged into each tailpipe, and yekes, the differences in mixture. I adjusted each jet to read in the prescribed range, and presto, now temps read within 8-10 of each other.

 

[SofaKing]

I have a stock 37, duel exhaust, no crossover. Duel SW temp guages, no thermostats. Had same problem with 25-35 temp differences. I have a gas analizer, so I pulged into each tailpipe, and yekes, the differences in mixture. I adjusted each jet to read in the prescribed range, and presto, now temps read within 8-10 of each other.

Very interesting, I've never used a gas analyzer. What kind of carb(s) and what jet are you "adjusting"?

 

[topchop]

SOLVED Need help understanding thermal dynamics...

Thanks for all replies.
Solved the issue. Troubleshooting 101 (start with the easiest) In the process of shutting off the heater, noticed that the passenger side thermostat became dislodged, and flipped 90 degrees. Unimpeded flow did not allow enough temp.
Tried Old Henry's solution with the single strand of thin copper wire, but could not stop a little weeping from both connections. Ended up with using a 1" long piece of 1 1/2" copper tubing above the stat in each hose to capture the thermostat to prevent movement.

Now temp is normal on both sides.

 

[JSeery]

Sounds like you solved it!

 

[supereal]

Lazer thermometers can be helpful, but they are heavily dependent on the coating of the surface being tested, and may show differences in actual places that are inaccurate.

 

[aandtman]

Sofaking, the gas analizer I used was a King model, probably from the 50's. My idle settings were way off the scale in both settings. The carb is a standard 37 carb.

 

[jake197000]

x2 on temp gun.

 

[FireEngineMike]

Re: SOLVED Need help understanding thermal dynamics...

Thanks for all replies.
Solved the issue. Troubleshooting 101 (start with the easiest) In the process of shutting off the heater, noticed that the passenger side thermostat became dislodged, and flipped 90 degrees. Unimpeded flow did not allow enough temp.
Tried Old Henry's solution with the single strand of thin copper wire, but could not stop a little weeping from both connections. Ended up with using a 1" long piece of 1 1/2" copper tubing above the stat in each hose to capture the thermostat to prevent movement.

Now temp is normal on both sides.

Glad you solved your problem. I had the same weeping with Old Henry's wire method (I suspect we used too heavy a gauge wire). I pulled the hoses, applied a little Permatex, and no more weeping.