Technical Radiator cap and getting hot

Jimmy six. Thank you for the pointers.

 

Stick a box fan in front of the radiator to simulate driving . If it lowers your temp you know which direction to go

 

Gary Macdonald. Thank you I’ll try it

 

Just for the record, water boils at 212 degrees when its not under pressure. If the temp is 220, I would expect it to be boiling.
Drill the hole (I always drilled an 1/8" hole, but 3/32 would work too) in the thermostat like others have said. The hole allows the air pocket trapped under the stat to escape. The hole needs to be in the flat part inside the sealing ring (like the little brass spot on the Summit stat shown), or get a stat like the Summit one posted. You already have 2 stats, drill the hole in the 185 stat, you have tested it and you know it opens at 185.

 

Gene koning I’m going to drill the hole! I found the original stat and the opening is twice the size of the one in there. Should I look for one like the original! More flow? Pic included

 

Put that one back in. Drill the little hole first.

 

Gimpyshotrods. That’s what I’ll do then. Thank you

 

The "correct" thermostats for these old engines are, in many cases, out-of-production, and have been replaced with substitutes that "might work". The trouble is, might is also might not work.

When in doubt, go original.

 

Sometimes the thermostats are slow to open, so the temperature on the gauge can read pretty high that first time as the engine warms up before the t-stat opens. But once it does the temp comes back down and then it can ride right where you want it at all day; but that first time can be worrying. I went through that for awhile and finally fixed it with one of these Mr Gasket t-stats

Different engine than your though, but the idea is the same; the replacement t-stats may be slow to open, and may be more restrictive as well.

 

Gimpyshotrods. I agree. The opening for water flow is at least twice the size of what I have in there now

 

Blues4u. I agree with what you’re saying

 

If post 36 shows the orginal stat the one in post 15 is the wrong one.

 

Yup, and sadly this is not uncommon.

Many of the "also fits" thermostats that I have seen simply are of the correct diameter, so they seal, and do not exceed the external dimensions of the original, meaning that it will "fit".

Will it "work" properly, or just "fit". That always remains to be proven.

If anyone has ever tried to buy the actually correct thermostat for a 351C, you will know what I mean. The ones that the parts store drone will sell you will lead to an instant overheat condition.

 

Be careful getting hung up on the flow rate of the coolant. It doesn't make nearly as big of a difference as people seem to think it does. The flow rate is directly proportional to the difference in coolant temperature between the inlet of the radiator and the outlet, but the same amount of heat is rejected. The heat rejection rate is determined by the radiator design and the ambient air conditions. For example, if you have a radiator that normally has a 5 deg temp drop between the inlet and outlet at 10 gpm of coolant flow, then by restricting the flow to 5 gpm, the temp drop will rise to 10 deg, but effectively the same amount of heat energy will be rejected to the air. There will be a slight change because of differences in coolant flow turbulence, pressure change across the pump, etc, but typically these are minor effects.

The only way to increase the amount of heat rejected by the radiator is to increase the air flow across it or increase the difference between the coolant temp and the air temp.

 

FrozenMerc. How did you guys get all this knowledge? Man oh man I appreciate all of you. I guess my concern with getting hot when not moving is centered around hauling a load. Going uphill, stuck in traffic, etc. I have more work to do!

 

Dan, most of us got the information the same way you did, someone shared it with us, or we learned it the hard way, by ourselves.
So, the lesson is, the more it costs, or the harder it is to fix, the better you remember these things.
Even with all this knowledge and experience, we are still learning too.

 

I’ve only fired and broke in a handful of engines, but always did so with just water and no thermostat. After break in if all was good I’d put a few hundred miles in the. With water and no thermostat they never got above about 145 degrees at highway speeds.

None were a Hemi, but Small Chevy’s small Fords. One 460. And a few 218 Dodge engines.
Has me
Wondering if there’s enough water flowing through the system with the stat out running at 160.

Just my thoughts.

Edit: Also timing was mentioned and we see you have tried between 4-7 BTDC. But is the timing advancing?

 

This is common knowledge for those who race circle track. NASCAR runs their engines right at 280 using water as a coolant. Their systems use a lot higher pressure and they changed the hardware to accommodate it, Threaded fittings, O-rings and a lot of other fancy stuff. For qualifying, they tape off the nose of the car for aerodynamics and air doesn't get to the radiator.

Just a thought, do you have your fan on backwards? In extremely cold climates, we used to reverse the fans on our semis to get heat off the engine to warm up the coolant in the radiators.

 

Fitting the fan backwards will not make it flow the air in the opposite direction. To do that you would have to run it in the opposite direction, or use a different fan with the blades pitched in the opposite direction.

 

Interesting on the Semi truck statements. My Dad only ran Cummins, but in his Pete’s he had a leather zipper cover and a air actuated fan. I put a bypass in it for him so he could let the sensor do the work or turn it on earlier or keep it off.
I tried for years to let him put a linear motor hooked up to vents, but he said it was too ugly on the nice of his trucks.

 

Extra to my post above, an electric fan fitted backwards will flow in the opposite direction, but it is not because the actual fan blade assembly is on backwards. It is because the direction of rotation will be opposite.

 

Put the cap on and pressurize the system so that it works correctly. Then see if you have an actual problem.

 

What temp are you wanting it to run at ? have you thought about using a water restrictor instead of a thermostat seeing as you know it will maintain 165 .

 

FIRST have you done some research in 1954 Chrysler groups to see what temp a 54 Chrysler actually runs at down the road and in traffic. 220 actually may not be hot at all if you have the right pressure cap and if that is what that style of engine likes to operate. If that engine was still in the car it came out of and was running down the road and in traffic with the full compliment of equipment that car would have come with what temp would it be operating at both in town and on the road?

It still makes my brain freaking hurt when guys take an engine that normally operated at over 200 in the original vehicle that it came in and then they shit their pants and piss on their shoes because that same engine wants to run over 180 or less when they stick it in an old car or truck. Then they drive themselves trying to fix a problem that was never a problem except in their mind.
If it puked coolant with the pressure rating of the radiator cap that the radiator was designed for and you had left at least half the space in the expansion tank on top for expansion, then you might actually have a problem. Big issue with that style of radiator is that a lot of guys under 50 have never been around one until they bought their first old rig and fill it to the top as they would a cross flow and that doesn't work. My engine came out of a 74 Pontiac Ventura (250) and the factory thermostat was 195 so running up around 200 wasn't running hot.

An issue on trucks with car engines in them is that quite often the fan ends up being too low on the radiator and the top half of the radiator has no air being pulled through it unless you are running a shroud. My 48 is example number one in that department. A full third of the radiator core gets no air drawn though by the fan and with the fan I had on it probably more like 55 % of the radiator was not covered by the fan. Temp shot way up at a stop light and dropped right back down to 183 going down the road with a 180 thermostat.

As for the thermostat no generic fits all will even fit that engine. It takes a designed for this application only thermostat and the factory 54 Chrysler runs a 180.
Rock auto shows several brands and part numbers.
1954 CHRYSLER IMPERIAL 5.4L 331cid V8 Thermostat | RockAuto

One thing I have done on my trucks when I have been towing heavy loads for a long distance is hull an old thermostat out and just run the body and no guts. That usually gives the restriction to get the engine up around the original thermostat temp after ten miles or so and you don't have to worry about it sticking. It's not worth a damn if you are driving in cold weather and need heat out of the heater though.

 

I have condensed this down to the posts that are the key to your solution.
1) Radiator cap pressure only controls the boiling point of the system, not the actual temperature.
2) If you don't have the issue without a thermostat, then the thermostat is likely the problem.
3) It is more likely to be that the new thermostat is not opening properly, or at all.
4) If it runs at 160 sitting still with the old thermostat, your radiator, pump and fan are most likely adequate.
5) Make sure the thermostat is opening correctly when installed, and drill the bypass hole in the plate.
I would be very surprised if your problem persisted after doing these simple things..........

Unless, of course, it was the fact that you didn't have the fan belt on and you don't want to admit it................

 

Budget36. As the timing is advanced the engine changes it’s tune. Smooths out. We are about 8-10 now

 

Alanp561. Fans on right as it moves a ton of air towards the engine

 

TA Dad I’m not sure where it should be. This is my first project and I can’t afford to screw it up. Without a stat and just water it runs 160 all day long. The 180 stat I had let the temp get to about 220 before I shut it off

 

Well said FrozenMerc. Cummins engine company, back in the eighties, had a “ low flow “ cooling system. The radiator hoses were about the sizes of heater hose! Lower flow, slower water, more temp drop for every GPM! It was successful, but it was discontinued, not sure of the reason. But it did cool the engine. I have an engine, on a tractor, that has no water pump at all and it cooled, just like the T.
I always thought folks got hung up on flow! There has to be flow. But low flow as long as there are no restrictions, is fine.
I think when folks put higher speed pulleys on the pump to speed it up, the increase in cooling actually comes from increased fan speed!








Bones

 

Mr48chev. I’m hearing your words. The original stat I posted a pic above says it’s a 165. I have not researched a bunch on the 241 rebuilt temps but I need to do I can really see what hot is. Radiator is huge and big air is moving through it. When the temp hit 220 with a 180 stat it wasn’t puking water at all. Maybe I’m just paranoid. Ha!