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| | | | Joined: Apr 2011 Posts: 523 Shop Shark | | Shop Shark Joined: Apr 2011 Posts: 523 | My truck started as a 46 1/2T truck. The radiator appeared to have a non-pressurized cap. Don't know if that was correct. I now have a 1955 235 engine installed and have gone to a new after market radiator (supposedly designed for the 46 truck) and came with a pressurized cap. What is correct - what do I need - do I have a problem?
Bob
BobS46
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Most likely, the 1946 cooling system was non-pressurized.
That 1955 235 would have had a 4 psi pressure cap on the radiator.
Does the aftermarket radiator/cap have a pressure rating?
If you have a heater, it should be able to take 4 psi.
| | | | | Joined: Apr 2011 Posts: 523 Shop Shark | | Shop Shark Joined: Apr 2011 Posts: 523 | The only thing I find on the cap is "0.9" stamped into the metal. Does not indicate psi, pascals, or furlongs per fortnight.
BobS46
| | | | | Joined: Feb 2004 Posts: 29,756 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,756 | That's a "0.9 BAR" cap which converts to 13 PSI. The radiator is probably rated for that kind of pressure, but you would need to get an ORM heater recored with a modern replacement if you intend to run that much pressure. Every pound of pressure raises the boiling point of the coolant 3 degrees, so a 13# cap would let the coolant go to 251 degrees before it boils. A stovebolt engine doesn't need to run that hot unless you're running air conditioning in a traffic jam, and even then it's a bad idea. A 7# cap should be plenty, which raises the boiling point to 233 degrees.
Jerry
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| | | | | Joined: Apr 2011 Posts: 523 Shop Shark | | Shop Shark Joined: Apr 2011 Posts: 523 | Thanks a lot, guys. Learned a little today.
BobS46
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