VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 1933 Master overheating

I'm stymied. I recently did a partial engine overhaul; new main bearings (to replace defective ones from a complete overhaul just a few thousand miles before) and new pistons and rings from Egge. Cylinders were honed, head magna-fluxed and surfaced, valve guides replace and valves and seats ground. The engine runs great and strong. I can drive the car down the road and even climb hills just fine, so long as I don't push it too hard. Going upgrade the engine warms up some, but nothing one wouldn't expect from a newly built engine. But then, once I start DOWN GRADE the engine heats up very quickly and expels the coolant through the overflow and out through the cap. This is a new problem that wasn't present before this overhaul.
I've cleaned radiator, replaced thermostat, pressure tested system. Adjusted valves, timing. Rebuilt vac. adv. & distributor. Chk. compression & retorqued head. Checked for any hydrocarbons in cooling system (10 PPM max.)
Any ideas out there? Thanks.

Have you checked your water pump? Fan belt slipping? I don't know if the 33 engine had a baffle plate in the block behind the water pump like the 35 block does. Overheating would occur if coolant flow is slow. Ignition timing too retarded will overheat an engine. Internal friction could be high when hot. How does the engine crank with starter when it's hot. Didn't leave a rag or other stuff in the coolant passages anywhere? Radiator hoses good?

I agree with 35 pickup man. The 33 does have a baffle plate behind the water pump and will cause the condition you describe. That would be where I would look next.

Your problem is most likely the water pump packing and seal. When you slow the engine the internal pressure (from the water pump) is reduced. Any air drawn into the system past the water pump shaft will expand and force water out the overflow. The hot engine (especially the back of the cylinder head) will provide more heat to force out more coolant.

First thing to do is to put an overflow tank on the outlet of the overflow tube. Hang the tank as high as possible. A temporary installation is ok. Then see if the condition improves. If so either make the installation more permanent or fix the cause or both. If you stop when it starts to over heat, check the tank and see bubbles it is air!

Oh yes, almost forgot the overflow system will work just as well as on your modern car if your radiator cap seals.

I would take out the thermostat and run it without one.If you do want to use one check the opening temp-I believe 160 is as high as you should use.I had the identical situation on my 32 (rebuild and all) and eliminating the stat cured it.

Yeah, and you could use one of those bright red one gallon Marvel Mystery Oil cans for an overflow tank, solder a U shaped length of copper tubing in the cap that will reach the bottom of the can to allow the coolant to be siphoned back into the radiator, and hang it as high as you can on the firewall!, of course, after you empty it and also improve the old engines performance!
Glad I thought of that, maybe when I get "A-Round-tu-it" I will make one for Klinkerbelle, even though she is a cool running old gal so far!
" If it ain't broke why fix it?"

:confused: :confused: :confused: :confused: :confused:

Thanks one and all for your suggestions. Some of the ideas have been tried, some not and one avoided so far (the baffle behind the w/p due to having to remove the radiator etc.). So at least I have a couple of new directions to go. I'll give these a try.
Thanks, LL