MG Car Repair: DGAV Weber Heater Hose Installation, flow control valve, heater control valve

Question
Hello Howard,
I have a 1975 Midget with the 1500 engine which I am in the process of putting back together after a rebuild. I bought a Weber DGAV carb and corresponding manifold but I'm struggling to figure out the routing for the heater hoses.
On the bottom of the intake manifold there are two tubes, one facing the front of the car and the other facing the firewall.
I have two fittings on what appears to be the choke regulator.
There is a tube that attaches to the lower section of the water pump and runs back along the side of the engine block with one straight out connection point just below the Smiths heater box and one connection point that T's off just below connection point I just described.
Finally there is the delightful heater flow control valve (only accessable from the engine compartment) with an inlet and an outlet and the inlet and outlet points on the Smiths heater.
Can you please give me some guidance on this little plumbing conundrum?
Thanks!
Fritz

Answer
Hi Fritz,
To get coolant to go in and out of the coolant operated choke on the Weber DGAV carb, you will need to install a "T" in the heater hose before the heater box and another "T" after the heater box but on the engine side of the heater control valve so coolant will circulate through the choke even when the heater is off. While it is true that you will loose a little flow in the heater box when the heater is on, it should be very minor as the hoses to and from the choke will be small and not bypass much coolant. It does not matter where you install the "T"s as long as one is on the hose going to the heater and the other is on the hose from the heater to get the "High" pressure from one hose and the "low" pressure from the other hose.
If you don't have the intake manifold connected either, you can just connect the inlet and outlet of the manifold in series with the heater since you don't need a heated manifold when the heater is turned off. A heated manifold is ok in the winter but decreases horse power in the summer. But you do need heated coolant to continue to circulate in and out of the choke heater year round. If you choose to do it this way be sure to put your choke "T" before the intake manifold so as not to cause coolant to travel through the manifold to get to the choke.
I hope this helps, let me know.
Howard