Afternoon Report:
Took Trudi for a run to DIYdiot DeepOh. 2.8 miles of heavy stop & go traffic. Retarding the timing back to spec got rid of WOT backfiring, though the motor still stutters from fuel starvation when attempting WOT acceleration. Having already swapped out the UTTERLY FILTHY, WORTHLESS GAS TANK for my CLEAN SHINY one from Tilly, the sole remaining source of dirt is the fuel line. Will replace another fuel filter, check it for debris, and inspect the line from tank to pump. The engine now idles very smoothly indeed, but FUEL STARVATION CAN CAUSE OVERHEATING! Must eliminate this possibility, utterly. Can use some JEGs line I have if I MUST.....
Coolant temperature still rises in steps equilibrium. 1st Step, ~210 F. This remains until upset by too much idling in traffic. When cruising, temperature actually will FALL as low as 205F at this first quantum. Wind clearly helps cool the system. Encouraging!
2nd Step, 230F. Idling in traffic eventually drives temperature up to 230F, where it then will stay, especially with some motion to help cool the system again. Once the system reaches 230F, temperature will not go below this by more than 1-2 degrees, unless possibly some sustained drive can occur. Even when stopped, spinning up the fan and water pump WILL cool the system several degrees. This helps prevent severe overheating, long enough to get home anyway.
3rd Step, 240F., Engine and coolant reach this temperature when approaching home on barrio streets and trailer park driveway. GOOD NEWS! The engine does NOT go over 240F when making the parking approach. At no time this afternoon did the "Hot" light come on. I still don't know IF or WHAT Chrysler specified as the proper temperature FOR the idiot light to come on, but ote that even close to 250F it doesn't appear. It DID appear briefly when the new gauge showed something around 255F. I DON'T WANT THIS ENGINE GETTING NEAR THAT TEMPERATURE, EVER!
Surmise: The engine isn't getting adequate coolant flow, from air or internal coolant. When in motion, the engine temperature temporarily stabilizes at some quantum reached as the car begins to move at 3rd gear driving speeds. When stopped in traffic, the engine coolant then resumes heating, until interrupted by vigorous air flow, coolant flow through the system, or both. Temperatures DO decline given adequate cooling fluids though! There is good cause to think this system can be cooled with upgraded cooling components.
Possible Problems: 1.) Fuel starvation: Fuel flow MUST be made RELIABLE and ADEQUATE. If, after one final filter replacement, the engine still stutters under WOT acceleration, then fuel line cleaning or replacement will have to be implemented. 2.) Cylinder block water jacket: Noting that on both sides, the cylinder block sides show significantly lower temperature (~195-200F) while the thermostat housing and water pump radiate at ~230F, with the cylinder heads showing ~ 215-220F, the possibility that extensive debris yet persists in the lower water jacket must be addressed. The wall plugs, one on each side, can be removed, and a fish wire can be inserted to ascertain whether significant debris remains in the lower jacket. If so, combined compressed air, pressurized water and vacuum cleaning all can and should be used to remove internal debris. Note: The engine was initially flushed with a water hose under normal house pressure attached to the heater intake hose after running the engine with an organic acid solution in the water jacket meant expressly for cleansing the cooling system. The engine ran throughout this procedure, forcing water through the cooling system from the pump intake, and out the top of the radiator via a plug-in spigot designed to direct coolant flow away from the running engine. This method has been used annually, and sometimes twice annually on my earlier MoPar B/RB vehicles. When the outflow tastes potable, the procedure is finished.
3.) Cylinder head gaskets: Given that this engine and car sat without running or care for several decades prior to an abortive attempt at restoration by the party that sold the car to me, it is entirely possible that the head gaskets have deteriorated to uselessness. Such HAS NOT YET BECOME APPARENT based on the engines clean combustion, and complete LACK of tell-tale residues of coolant in the crankcase oil, or crankcase oil in the coolant. No water vapor can be seen or even felt in the exhaust. No oil smoke can be detected. The emissions test, in fact, at 196 ppm for hydrocarbons, was REMARKABLY CLEAN. OIL PRESSURE remains respectably high, around 45 psi at any engine speed over 600 rpm. A compression check will be performed when time for such avails. At present, cylinder head gasket failure is deemed extremely unlikely.
