1916 Dodge overheating

[Jbjgo]

I am hoping there will be some information to there that might help me with my quandary.   My 1916 Dodge started overheating this year.   Last year ran fine and earlier this year.   I did have a very small water leak near the #3 exhaust port and I tried to fix using some high temp JB weld and high temperature sealant which seemed to work as ran fine without leak last year.   When I took my car to a local show only 7 miles away it boiled over quickly and I lost nearly 1 1/2 gallons of water on the trip.   Same happened on return.   When overheating the motometer was topped out.   I tried to isolate the problem and tried running the car at high idle and the water seemed to rise in the header tank (starting level was just above defector plate) until there was a constant overflow out the tube.   I checked the compression and equal in all 4 cylinders.   I have a device that tests the air above the coolant to determine if there are combustion gases in the coolant and test was negative.   I took off the lower radiator hose and flushed hose water thru and seemed to back up a bit so I took the radiator out and flushed and seems to flow just fine.   The radiator by the way is a new core by Breastworks and I was able to inspect the tubes using fiberoptic device and they seemed clear.   I inspected the water pump, especially the impeller which looks fine and did not rotate on the shaft.   I just backlashed the block and radiator until was running clean.   The only additional piece of information, I hate to admit, was that I used a product called nanotechnology block and head seal.   Not sure if this might have clogged along the way but now seems to flow well.

My plan is to reinstall the radiator and run.   Possibly something partially blocking the coolant was dislodged during my working on the radiator and hoses.   I would greatly appreciate any additional information that might be of help.  Thank you everyone   

[nearchoclatetown]

What caused the water leak at #3 exhaust? 

[Mattml430]

If it boiled that quickly and then got worse on a high idle I’d say it’s the head gasket. You said the radiator has good flow while the engine is running so it shouldn’t be blocked. Does it have a copper head gasket or a composite head gasket?

[Jbjgo]

Not sure about what caused the leak.   The water jacket is close to the exhaust port and I suspect over 100 years rusted thru or a casting defect.   I did check the compression and all cylinders equal and normal.  There was no evidence of exhaust gases in the coolant.   The head gasket is a new copper gasket.  

[Mattml430]

21 hours ago, Jbjgo said:

Not sure about what caused the leak.   The water jacket is close to the exhaust port and I suspect over 100 years rusted thru or a casting defect.   I did check the compression and all cylinders equal and normal.  There was no evidence of exhaust gases in the coolant.   The head gasket is a new copper gasket.  

If you’ve got a new copper gasket you’d definitely think it would be fine. 

[nearchoclatetown]

Magneto or distributor, should be a Delco. Did you do anything between then and now?

[Mark Gregush]

Magneto would be Eisemann G4-1st. Simms was used later. 

[nearchoclatetown]

And I don't think Simms was ever used on domestic DBs.

[Mark Gregush]

1 hour ago, nearchoclatetown said:

And I don't think Simms was ever used on domestic DBs.

Maybe not, but it is listed in the 1914 to 1927 Master Parts list starting at car #'s 266444  4X and 373830 C4. The notations show for non domestic parts orders to order from DB and domestic to order from manufacture. 

[Jbjgo]

This is a long story, but the engine, drive train and frame are 1918 and the distributor is a Northeast.   JIM

[gossp]

I would try driving it with the spark greatly retarded and see if it’s less hot… or just static test timing. Cars with heavy flywheels behave great with too much advance but get hot fast. 

[cutdown]

Retarding the spark is likely to cause hotter running.

 

Reading this, you seem to have removed and cleaned the radiator and flushed the engine since the overheating [ is that correct? ].  Does it now over-heat??

 

You described the water flowing out the overflow also after a shorth time, [ or did you??? ]. That would indicate combustion gases in the cooling system.

 

You mention adding some stop leak type crud to the cooling system and that is also likely to block the radiator [ or the block ] enough to cause overheating [ possibly ].

 

In order to assist you with the diagnosis, you need to be precise in describing the problem and the timeline for your observations,  otherwise we are all guessing.