Technical Flathead Right Side Temp: RESOLVED

Hello all,
Yesterday was the first really warm day here that I was able to get the car out and drive it around.
I noticed the right side was running hotter (220-240) than the left side (180-190).
This occurred during around town driving. stop and go and speeds less than 40. At sustained cruising speeds above 35 the temp would come back down to normal (180-190) on both sides.
I have done a search here and will check and try the many different suggestions this weekend. I didn't have any time last night for troubleshooting when I got her back to the barn.
My real question is... if the ford V8 flat head is basically two 4 bangers welded together and sharing a crank why would the right side run hotter than the left side? all things being equal...all things should be equal right?
Thanks for the input.
Chappy

The details: early 51 truck block, EAB heads, Mallory dual point with Pertonix rebuilt by Bubbas' for this application, new Griffin rad, 4" merc crank, isky max 1 cam, vintage Edmunds 2x2 intake, dual ford script 94's set up progressive by Vintage Speed, complete engine rebuild less than 3000 miles ago (About $5k). all in a 30 ford coupe, no hood, 6 blade Mechanical metal Fan

20180614_220025 by Chappy444 posted Jun 15, 2018 at 7:43 AM

 

I have no clue, but very cool gauge !

 

Yes there is no cross over of the coolant until it reaches the radiator. Seems if one side is over heating, all the coolant would get that hot pretty soon. Maybe a quirk of the gauge? Does it blow out the coolant? Have you checked actual temps with an infrared thermometer?

 

Thanks. Its' a Westach Gauge product (aircraft/diesel applications mostly)
I had to machine aluminum spacers to make them work with the '30 cluster clearance issues.
https://www.genosgarage.com/product/westach-dual-temp-kit-white/westach
Chappy

20180331_205212 by Chappy444 posted Jun 15, 2018 at 9:16 AM

20180401_200153 by Chappy444 posted Jun 15, 2018 at 9:16 AM

20180402_054916 by Chappy444 posted Jun 15, 2018 at 9:16 AM

 

I would suspect maybe a flow problem, could be the water pump maybe. Interesting to me is the guy that rebuilt my flathead a few years ago said the factory never really got all the casting sand out of those blocks, he had a copper tube that he irrigated the block hung upside down over a wheel barrel to flush them and catch the sand to see how much actually came out. He got about a 1/4 of a coffee can out of mine. That motor always ran cool both sides were monitored separately.

 

Mine always runs a little warmer on the right side. But on a hot day in traffic a couple weeks ago it got a little scary. I’m looking into it. By the way that’s a really cool gauge.

 

thanks Sheep, i wasn't there for the rebuild, supposedly all the standard machine shop stuff was done, hot tank, flush, flux, bore, deck, etc. etc.
I will get on the trouble shooting this weekend I hope. The oldest daughter is home from college for her birthday this weekend, so i am finally going to be able to get to replacing the struts on her OT car, get it aligned, and i am sure it is due for an oil change. Maybe I will get to the hot rod sometime on Sunday afternoon LOL.
Chappy

 

there could be a couple reasons why one side would run hotter than the other. many blocks just weren't machined well. the motor in my current roadster was ten thousandths off on the deck height left to right. i had to get the heads milled anyway so I corrected the difference that way. other thing could be thermostats. if you weren't looking for hit things like that are easy to miss.
my guess though is a difference in your gauge. swap leads to your sending units and see what happens, then swap sending units. another thing to test is just see if the resistance is the same on both sending units when they are dead cold. last or first lol. get an IR temp gun to see if they are really different

 

Dave, what is "a little scary"? mine creeped close to 250 at one point...that was scary for me...
Chappy

 

I'm with Revkev, do a quick switch on the sender leads and see if the problem stays the same. Maybe the gauge is off on one side?

 

This is a new development, the only thing different between yesterdays drive and all the other driving i have done where both sides read the same was the ambient temp and humidity was considerably higher yesterday. i will get into trouble shooting over the weekend (i hope)
The gauge and senders are designed for aircraft applications....i would like to think they are fairly robust. and they are new (just installed them around February), not that new = good all the time.
I ohmed the senders cold before installing. specs are 100degrees is 1750 Ohm, 212degrees is 212 Ohm with a system accuracy +/- of 4 degrees)

My main question is really more general about why these flatheads tend to run hotter on the right than on the left.
It's my first flathead and I am trying to get my head around this. Most of the stuff I have read this is not unusual and most people get into the fix without covering the why.

thanks for all the responses
Chappy

 

Great suggestions provided. I would recommend checking the bottom radiator hose to be sure it is not collapsing and restricting the flow. Speaking of which...are you running thermostats? If so, check and see if it's fully opening up.

 

Pumps,new,old or rebuilt?

 

Rebuilt, maybe 3000 miles on the entire build
Chappy

 

I had a difference in Left vs Right side temperatures - Turned out to the difference in the exhaust system one side was holding the exhaust in the block longer causing that side to run hotter. Corrected the exhaust problem, both sides ran the same 36fordguy

 

aircraft or not, you start simple and work up. ALWAYS. this is the same procedure an aircraft mechanic would do.

flatheads do not tend to run significantly hotter on the right side. mine runs within a few degrees according to my IR temp gun.

if this is a new development, you have a bad thermostat, a bad gauge/sending unit or possibly something else like a bad gasket or a cracked block. pull your plugs and check them as well.

 

Agreed. One side running hotter is not an inherent problem. And the idea that since they come together at the radiator and should “even out” is not true.
You have a constriction issue at the hot side. Or a poor performing water pump.
Or exhaust g***es entering that side of the cooling area.

 

Revkev. agreed. As i said, my plan is to attack it on Sunday after I finish working on my daughters car.
plan of attack:
verify full coolant... don't see any leaks anywhere i park but i will check level anyway
check belt tension
open plug on top of right side head to make sure no air trapped at the top of head
pull and read plugs
check oil for coolant
ohm senders at gauge end with engine at operating temp
swap sender leads on the back of the gauge (senders are hard wired on the sender end)
verify temp readings with my temp meter
if all that checks out, i will remove/replace thermostats and go from there.
thanks for all the replies.
Chappy

 

Normally the right side will run about 5 to 10 degrees hotter than the left at normal operating temperature which is 180. Don't ask me why, there have been all kinds of theories. I buy my thermostats from Bob Shewman, they work better than every other one I have tried. Who rebuilt your pumps?

 

Mine runs hotter on the left side, as sitting in the truck.

 

Flowmeister, you are correct. I am just coming off a bout with food poisoning and had me confused. It is the left side that runs hotter.

 

Mine also runs 8 degrees hotter on the driver's (left) side. I surmised that it has something to do with the heater being on the p***enger side holding more coolant, but that's just a guess. We had this same discussion on "The Ford Barn" about 6 months ago, and here's what "JWL" (a guru over there) said :

"One more time---- The ports are different lengths from left to right bank. With the longer intake port and shorter exhaust port holding a slight advantage over the short intake port with longer exhaust runner of the opposite bank."

Does anyone know which side has the longer intake port and shorter exhaust port? I have never even thought about it.

 

What RMR&C said ,mine shows 195 -200 but is really 175 degrees with a infrared hand held reader.


Sent from my iPhone using The H.A.M.B. mobile app

 

Check your fan belt, easy and real cheap. They were always a problem back when they were real big, the weight would throw the belt out and let one of the pumps slip. New small belts, not so much, but still could be your problem.

Bones

 

You know, you might be on to something here. Since the '50 on cars used separate belt for each pump, what if one belt wasn't tightened enough? It would slip and the water pump wouldn't turn as fast. I think I'll check the tension on both of my belts.

 

Talk of the belt got me thinking... I just had the generator off and I have one belt that runs both pumps and the generator and a separate belt that runs the fan.
I just checked it and if I push at the halfway point between the pump pulley and the generator pulley I get about an inch of deflection...which I was told is about right as to not overtighten the belt and damage the pump seals.
Chappy

 

You are right ^^^^^.

 

My Merc runs pretty much equal on the highway around town the right bank runs a few degrees hotter. But I’ve never had it run over 200 anytime.

 

I'm worried if mine gets to 200*.....My left side seems to run hotter per my infrared.....21 stud stock engine......

 

Well I got the struts on the daughters OT daily and dropped it off at the alignment shop...while I had some time I figured I would work on the 30.
I drained the coolant and gave it a flush.
Measured coolant out was almost half gallon less than the amount of coolant I put back in.
I just drove the car in 87 degree heat for over an hour in mixed driving and temp never went above 190.
The only thing I can think went wrong is that right before it started running hot I had parked it at my friends house pointed down hill in his drive...its a pretty steep drive... maybe a combo of angle and low coolant caused an air bubble somewhere or something. Either that or maybe I have a sticky thermostat. I will continue to monitor and update if the problem returns.
Thanks again for all the helpful insights
Chappy