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For those with M20 swaps - heater question

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Getting the ball rolling on my M20 swap again and ran into something.

For those who have swapped in M20s, did you flip the heater outlet on the back of the head around? I know the direction of the heater core/02 side because the heater valve side is the intake for the heater core, but I'm not sure if the M20 feeds from the water neck on the back of the head, or if that is the return for the heater core.

Any thoughts/pics?

Cheers,

Andrew

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Obviously the best place for the valve is to be on the hot water outlet from the engine but you won't have too many issues if it is on the return.

This will still restrict flow through the core and once it is static this will achieve the same ends.

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On the M20, the coolant flows out of the back of the head into the heater core, back out to the coolant pipe to the thermostat housing. The core is supposed to get the hottest coolant to give you maximum heat as quickly as possible.

That's what I did. I installed to outlet pipe at the back of the head backwards since it is symmetrical and hook it to the heater valve side of the core.

In my case, since my car is gutted, I cut out a rectangle section out of the firewall at that location in order to have easier access to that pipe from inside the car. Otherwise, it is a nightmare to reach and fasten those bolts, or even to disconnect the hose. The back of the head is just too close to the firewall. I then fabbed a cover with 4 sheet metal screws and a strip if foam to seal it. It works.

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Thanks for the replies guys, much appreciated.

Looks like I'm going to flip the water neck around. Yeah, its definitely a tight squeeze on the back, but the engine has got to come out one more time so it should be pretty easy once its out.

On a side note finished the rest of my wiring tonight and installed a fuel pump. Getting closer. Still lots to do but glad I'm back at it.

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