I set up my truck in series with the heater flow from the heads->heater core->model E->water pump. Noticed this winter I had poor flow to my heater core resulting in not much heat in the cab. If I shut off the heater fan and waited a few minutes I would get a burst of hot air, implying poor flow. Never froze the reg or had any fuel starvation/flooding issues though.
When I had the motor apart I put a new water pump in just in case, checked the hoses for restrictions and blew out a shop rag the previous owner had stuffed into one of the heater core hoses and then obviously forgot about on reinstall. Problem solved!
Except the heater core still doesn't produce much heat. Both hoses are warm now but the outlet hose feels cooler. Does the pump not develop enough pressure to push coolant through both cores, and they should be installed in parallel instead?
Model E in series or parallel with heater core?
Re: Model E in series or parallel with heater core?
Been away for a while. I've been very busy this winter and just have not had time to check in.
Your heater core is probably just partially plugged. Think of it like a miniature rad with dozens of very small tubes. The tubes begin to plug and when enough of them are plugged it just won't produce enough heat as it restricts the circulation of the coolant. You could try disconnecting both heater hoses and reverse flush the heater core, however success is usually minimal, but I have seen it work. Lots of times the core will just leak through after a thorough reverse flush. The heater probably was struggling to provide heat prior to the installation. You just weren't actually aware of it. The rag would have slowed flow causing stagnant coolant to build sludge. Installing the convertor does not normally affect the heat, however with a rag in the system I am surprised you even had enough to keep the convertor from freezing up. Keep in mind that a water pump actually sucks. the coolant through the block. It enters the pump from the bottom of the rad and then pushes it into the engine through the top. Your heater core should be the same. If you have an upper and lower hose on the heater core the coolant should go head - lower heater hose-upper heater hose back to pump. Depending on the vehicle model there should be an opening allowing you to attach the heater hose directly to the pump. The convertor can go inline on either the inlet or outlet of the heater hoses however the coolant will be cooler entering the heater if it is installed on the entry hose. If the heater core is clean the convertor will have a minimal impact on the available heat, however if the core is partially plugged or poorly designed it will impact the available heat. In thousands of conversions usually heat was not impacted unless there was something wrong with the circulation.
Your heater core is probably just partially plugged. Think of it like a miniature rad with dozens of very small tubes. The tubes begin to plug and when enough of them are plugged it just won't produce enough heat as it restricts the circulation of the coolant. You could try disconnecting both heater hoses and reverse flush the heater core, however success is usually minimal, but I have seen it work. Lots of times the core will just leak through after a thorough reverse flush. The heater probably was struggling to provide heat prior to the installation. You just weren't actually aware of it. The rag would have slowed flow causing stagnant coolant to build sludge. Installing the convertor does not normally affect the heat, however with a rag in the system I am surprised you even had enough to keep the convertor from freezing up. Keep in mind that a water pump actually sucks. the coolant through the block. It enters the pump from the bottom of the rad and then pushes it into the engine through the top. Your heater core should be the same. If you have an upper and lower hose on the heater core the coolant should go head - lower heater hose-upper heater hose back to pump. Depending on the vehicle model there should be an opening allowing you to attach the heater hose directly to the pump. The convertor can go inline on either the inlet or outlet of the heater hoses however the coolant will be cooler entering the heater if it is installed on the entry hose. If the heater core is clean the convertor will have a minimal impact on the available heat, however if the core is partially plugged or poorly designed it will impact the available heat. In thousands of conversions usually heat was not impacted unless there was something wrong with the circulation.
Re: Model E in series or parallel with heater core?
As above, make sure your heater core is plumbed to avoid air lock and ensure complete filling, i.e into the core on the low port, out on the high port.
Re: Model E in series or parallel with heater core?
Took a look at it and it's going into the core on the high port, that's how it was when I bought it so I left it that way. Can't expect much from a guy who left a rag in the line I guess, and all the vacuum hoses were also a total mess when I bought it, with a big vacuum leak and the choke stuck on compensating... got a good deal on it since I was planning to replace the carb with a mixer anyways. I barely drove it before putting the propane system on so likely the heater already wasn't performing as you say. It seemed to blow hot but it was also summer.
Surprised it flowed at all with the rag myself, but it was a cloth rag and looks like it got wedged up against the suction barb going back to the water pump, and didn't block the flow completely. The old pump was fine when I removed it but for $50 might as well swap it while the timing cover is out instead of lose it later.
I'll swap the hoses around and flush the core (gently, I agree old cores like to leak). Good to know the converter isn't a significant restriction.
Surprised it flowed at all with the rag myself, but it was a cloth rag and looks like it got wedged up against the suction barb going back to the water pump, and didn't block the flow completely. The old pump was fine when I removed it but for $50 might as well swap it while the timing cover is out instead of lose it later.
I'll swap the hoses around and flush the core (gently, I agree old cores like to leak). Good to know the converter isn't a significant restriction.