Losing water? 48 flatly new build! Today I did a radiator carbon test on a warm motor went well test stayed green no yellow. Had re-torqued alum heads to 55ft-lb in sequence prior to test. As I was doing test on the new Brasswork radiator I noticed with cap on and rapped the RPM’s up I could get water to puke out of down tube from over Flo ? And it really flowed quite a bit. This could be the culprit. Wondering why.. then as watching that the left new water pump from speedway (high flow)was sending a faint pulley spray on fender? After shutting off motor and removed the new radiator cap to my amazement I watch the water slowly rise in neck and trickle out?. Figure with what had ran out on floor it should be low! I’m new at flatheads this is puzzling. Thinking a compression test might be needed. But oil is very clean and plugs are new. Any ideas ? motor was not hot. I have drove it 40/60 miles round trip and had to add a gallon or so of water. But really no sign of where it go’s other than later today finding the radiator dump tube flushing out. Thank you fellow rodders !
New water pumps are supposed to be the “improved” type with bearings and seals. It shouldn’t be spraying. Replace it with a good one.
Open or Pressurized cooling ? Are you using 2 temp gauges , 1 per side & thermostats, On the Flat head I had , I was using SS tube from rad to outlet of block /head, I used the hose clamp to hold the Sat against the outlet so it could not capsize , Same can be done with all rubber , you could allso take a pipe & snug fit inside hose , a-just depth & only use 1 clamp @ outlet , Just @ time I was Lazy
Put just enough coolant in the radiator to cover the top of the fins and see if things improve. Is your cap and system pressurized?
My fill neck is positioned to be under hood dummy on top. It’s pressurized system with reservoir. Custom made by brassworks. Can’t really see into radiator for fin line. System holds about 5gal motor/Radiator. I do realize some hold what they want.
I'm running a 4 core Brassworks radiator on my 8BA powered A with early heads and haven't lost any water, I do have 160 degree thermostats on both sides. I did install an expansion tank and run a 6 pound radiator cap. You have a real problem if you're losing a gallon of water in 60 miles, I would think you should be able to tell where the leak is unless it's internal and going out the exhaust. The expansion tank is in the first picture, I have several thousand miles on the car and have never had to add water.
My radiators a four row also. Exhaust is new out back straight pipes 1 3/4. I kept an eye on them no moisture other than condensation spits on start up. I tell you if it’s that radiator building presser from a air pocket I’ll be amazed tomorrow I’m letting it run with out cap to try burping the system just to see.
There should not be a reason why you would have air trapped in that engine the way it is all set up. There is nothing on the system that is higher than the filler neck on the radiator and although you could get air trapped behind the thermostats on first fill that should be a non issue by now. Over filling the radiator of a top tank radiator is the number one reason for one puking coolant. I had a go around with a buddy of mine a few years back who had his first old car and it was the first car he ever had that didn't have a cross flow radiator and he would fill the radiator to the top and it would puke coolant out as soon as it got warmed up to operating temp. From looking at it I'd have to believe that you have a radiator cap intended to work in conjunction with a coolant recovery tank and you do not have a coolant recovery tank and when it releases pressure that should flow into the recovery tank to be returned to the cooling system when it cools off there is no tank. That and I would fill it until there is just between 1/4 and 1/2 inch of coolant in the bottom of the filler neck and go from there. Measure up from the seam on the tank to see where a half inch or so is above the core and figure out where that is in the neck.
I was wondering if you drill a small hole in your thermostat flange, I started this practice years ago when I put a thermostat in a Model A. Model A's will force water out the drain due to the upper hose coming straight up toward the filler neck and open drain tube. Modern cars have a thermostat bypass built into the system to allow circulation before the thermostat opens.
This is how I do an empty engine/radiator coolant fill that works on my heaps. I fill the radiator about a gallon shy from full, rad. cap off, start the engine and let it come up in temp. Watch the temp gauge for the thermostat opening. The temp. will fluctuate at first, because of the trapped air. Once the gauge shows the thermostat starting to open, the air will start being purged. After a minute or two I shut down the engine and let it cool a bit, top off the coolant, install radiator cap, start the engine and let things come up to operating temp. Then I let everything cool completely and check the coolant level again, adding more if it needs it, making the level about an inch from the neck. Good luck!
The 59AB in my 40 would mysteriously loose water until it would overheat. Tried and tried, to no avail, to find it. The autopsy when it blew finally showed the culprit. See the crack between the valve and cylinder. Worst case scenario, hope that yours is easy.
I really went over block. Hoping nothing was lurking under surface. Motor was built with old speed equipment years ago. fingers crossed. Letting it sit for the holidays per wife’s request.
Can you make an adapter for the radiator cap that would let you pressurize the system to about 5-7 lbs with air from a compressor ? Then listen for a leak or try spraying soapy water around suspected connections..........
Finally the cars running at good temps. No leaks ! I found the water level it likes. Replaced water temp sending unit it runs cool around traffic and 180-195 at high speeds 2600 rpm. Fan kicks on at set times. It’s a great feeling to have a great running flatty. Happy Rodding
It's a pressurized system so once it's up to temp the coolant will always rise when you remove the cap while it's still hot.
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