DIY - Heater Core replacement using 124 Core

fiatmonkey

fiatmonkey

Tim Hoover
Folks,

I recently posted a thread in Workshop forum asking about replacement heater cores. @Jefco suggested a 124 core with some customization to the heater box. He posts pics of the size differences here I used it as direction and did the following:

I bought a core from VicksAuto
Removed the entire heater box (actually had a spare complete box from a 74 project in the works)

Removed old core, all cables and fan. Next test fit the new core to get an idea of the fitment and what needs to be modified. There are 4 tabs on the lower section of the box that I removed and allowed the core to sit lower:

IMG_3506.JPG
IMG_0656.JPG


This definitely helped, but needed a little more space AND it also caused a problem where the heater core now was interfering with the actuator for the lower heater door. To solve this, I modified the actuator arm to shorten the throw and the length of the arm-end that connects to the cable.

IMG_4830.JPG
Allows it to clear AND shortens the distance of the throw so a quicker/easier opening of the door.

I then trimmed an edge off of the fan shroud as I needed about 1/8 of inch more clearance to get the box to close completely. The other option was to leave the shroud out, but I thought that would make the fan far less efficient.

IMG_6832.JPG
IMG_7839.JPG


Making sure the fan has clearance and everything fits perfect! A lot of work (maybe?) but was about 1 1/2 of my time today.

IMG_1213.JPG
 
Well done, Tim!! :D
It takes a TRULY dedicated X-head to go through the pains and agonies to achieve what you have just achieved!!

cheers, IanL - NZ
 
Very nice work, Tim! I did mine in 2015, in the car, and only took pictures of the cores, not the fitment, so my previous post was from memory. I wish I could have worked on mine at a workbench, too!
 
Great write up.

When you shortened the arm for the intake air door, your tab for the the wire to interact with is very short. It looks like there is enough material where it could have been longer. Is there a different reason for making it so short? Or did you feel confident in the short tab because the wire has ‘preload’ towards the inside bend of the tab, plus how stiff the wire is so it is unlikely to come off?

Thanks, nice work and great pics to illustrate what you have done.
 
kmead said:
Great write up.

When you shortened the arm for the intake air door, your tab for the the wire to interact with is very short. It looks like there is enough material where it could have been longer. Is there a different reason for making it so short? Or did you feel confident in the short tab because the wire has ‘preload’ towards the inside bend of the tab, plus how stiff the wire is so it is unlikely to come off?

Thanks, nice work and great pics to illustrate what you have done.
Click to expand...
Karl I definitely removed more than needed however the important thing to note is it's not the overall length of the arm, but the point at which it bends. This determines how high it will go when in full open position. What I don't show is where it was interfering with the core itself. I don't have @lookforjoe drawing skillz, so won't attempt to illustrate it :)
 
Tim, I like this.
Without having the heater box in front of me to look at, I'm a little unclear of the modification to the arm....at least in respect to the arrangement of the cable's new reattachment.

In this photo, it looks like it was taken after cutting the arm off but before remounting the cable?
IMG_4830.JPG


I'll use the prior photo to illustrate my question. Where did you cut it (near any of the colored lines)?:
IMG_0656.JPG


And after cutting the arm, how did you reattach the cable? Perhaps bend a new tab over on the remaining portion of the arm? Or did you use the other existing tab on the opposite side of the lever? Or something else?

Thanks for the additional insight Tim.
 
After rereading your description and looking at your pictures again, I think I see it better. Is this the remaining arm (after shortening) that has been bent over and narrowed to make a new tab?
IMG_4830t (1).JPG


Sorry, I'm having a bit of difficulty making out the image - guess my eyesight isn't what it used to be.
 
Dr.Jeff said:
After rereading your description and looking at your pictures again, I think I see it better. Is this the remaining arm (after shortening) that has been bent over and narrowed to make a new tab?
View attachment 15481

Sorry, I'm having a bit of difficulty making out the image - guess my eyesight isn't what it used to be.
Click to expand...
Yes - that's the result; a shorter overall arm with a bend and a cut out in the arm to allow the cable to attach. The cable slides on just as it did before. The nut holding the sheath in place keeps the cable from sliding off the arm, or at least helps. Make sense?
 
Good idea, but I have one question, why can I make a 1 inch spacer to put between the top and bottom parts of the heater box? This would make the box taller, but I could remove 1 inch from the defroster plastic piece that goes to the dash. Seems easier than adjust the flap correctly.
 
Remove spacers and modify linkage or make box taller- fair exchange! should only need 1/2 in; difference in thickness only about that.
 
There might have also been another write up on this conversion. I seem to recall two different methods have been discussed. One was something about trimming some interior tabs/ledges to allow for the extra room needed? Anyone have another link about this?
 
Okay, you guys convinced me to order a 124 heater core new from vicks. I will be bench fitting this core since all the parts are sitting on a table in my office. I will try to make room inside and find out how well this works.

I will not be doing this for about 2 weeks because of travel.
 
toddr124 said:
Okay, you guys convinced me to order a 124 heater core new from vicks. I will be bench fitting this core since all the parts are sitting on a table in my office. I will try to make room inside and find out how well this works.

I will not be doing this for about 2 weeks because of travel.
Click to expand...
Looking forward to hearing/seeing how you do it and safe travels!
 
Hi guys I have a question regarding this modification to fit 124 heater core.
Depending on how much you cut out at the top or bottom does that alter the inlet and outlet position for which the pipes and heater valve come out of? Because the heater box has those areas with the cut out for it I’m just wondering if it still stays centred to them after you alter the inside
 
Anthonyp said:
And everything fits and works good ?
Click to expand...

Welcome to the forum!

This is only for non AC cars - that is what you have? Check the link Yves added - it has very detailed pics of the mod.

Fill out your sig with your X1/9 details - that will make it easier to respond to questions
 
You must log in or register to reply here.
Back
Top