Heater Connection on Back of Head

[Brianmc02]

Replacing the 121 head that had cracked on my '74 2002.  Got a replacement head from a fellow forum member, and had everything redone at a local machine shop.  Now I'm starting to reassemble things, and I see that I need to change the heater connection port on the back of the head to the later, larger diameter fitting. 

 

A 22 mm box wrench, a hammer, and some swearing have failed to break it free so far.  Anyone have any tips on this, or should I look into swapping hoses instead of fittings?  I have considered breaking out my impact wrench, but I'm not sure if that's taking a risk.  Do not want to damage my "new" head at this point - too far into it to start over.

[halboyles]

I have taken that fitting off of many heads with an impact wrench but have also broken a couple off inside the head.  I don't know if it would be safe to heat the head around the fitting slightly before hitting it with an impact.  I"m sure some of the engine builders out there will have suggestions.

[coloincaalpine RIP 2021]

Always taken them off with an impact without issue. Won't do any good to replace the hose, if you do, it won't fit the heater control valve.

[jimk]

Cross your fingers and anything else that you can when you decide to take it off.  There was a unlucky guy on the S14 board that decided to go at it and ended up with a head that had no threads left.  That head is a hell of a lot more expensive.

[stephers]

A little heat from a propane torch will be OK   a LITTLE only, don't use an oxy/ac set up , way too much heat  

 

One other question, 121 head on a 74, they should have an E12 head unless you have changed pistons ?

[jgerock]

Soak the fitting in some Liquid Wrench then try again.  

 

If it won't come off, you can use an adapter similar to this one (and a short piece of the smaller heater hose).

[Brianmc02]

Success!  PB Blaster last night, and a 3 second pull on the trigger of an impact wrench this morning, and it zipped right out.  Glad I didn't have to do that one with the head in the car.

 

And the engine is a swap - an old Eric Kerman rebuild from the late '80s.  So the head and the pistons match.  Probably has less than 30k miles on it at this point, and hopefully the repaired head will make the car fun to drive again.

[coloincaalpine RIP 2021]

Atta Boy!

[TobyB]

However, if it hadn't come out, many cars are running around with large heater cores and valves

and small head nipples (and vice versa) using half of each hose and a splice.

 

Personally, I only take those out of heads that are trashed- as Jim says, it's a LOT of work

to repair the head if it's so electrowelded that the aluminum threads come out on the steel nipple.

 

t