Steve Abbott
SILVER Star
I am in the process of refurbing my heater box and installing a later heater core in a '65 FJ40. I used a Four Seasons 91659 that fits '68 and newer.
I started by wrapping the top, bottom and sides of the heater core with adhesive backed 1/4" closed cell rubber foam. The foam came from Amazon.
Next I made some mounting brackets out of some 1/8"x1/2" flat bar. You can find the flat bar at Home Depot, Menards or Lowes. I had to weld a tab on one of the brackets to keep the bracket from contacting one of the connections on the heater core (not pretty, but it gets the job done). I test fit the brackets over the ends of the heater core to make sure they fit a little snug.
Next I placed the heater core in the heater box and positioned the brackets so they were centered on the factory holes in the box and marked them with the hole locations.
I drilled the brackets and tapped them for 4mm stainless screws.
Once that was done, I reassembled everything to make sure the holes lined up. The new heater core needs to be tilted a bit to fit the box since the new one is narrower than the old one and the spacing of the connections width-wise is narrower. It won't fit unless it's tilted. Don't worry about the foam sticking up. Once the rear cover is on, it compresses and forms a seal at the sides of the heater core.
Everything seems to fit pretty well.
I need to figure out a good way to seal up the box where it is circled in red below and also clean up how the foam looks. Maybe some black aluminum tape??
I'm not 100% satisfied with the foam. It seems OK, but I'd like to find some that is more resistant to tearing. If I can find that, I'll be a lot happier with this project. As it is now, the rear cover fits nice and snug once the foam is compressed and the heater core doesn't move at all when I shake the box. Next is to source some hose and elbows to feed the defrost. If you have any ideas for improvements, let me know. Thanks!
I started by wrapping the top, bottom and sides of the heater core with adhesive backed 1/4" closed cell rubber foam. The foam came from Amazon.
Next I made some mounting brackets out of some 1/8"x1/2" flat bar. You can find the flat bar at Home Depot, Menards or Lowes. I had to weld a tab on one of the brackets to keep the bracket from contacting one of the connections on the heater core (not pretty, but it gets the job done). I test fit the brackets over the ends of the heater core to make sure they fit a little snug.
Next I placed the heater core in the heater box and positioned the brackets so they were centered on the factory holes in the box and marked them with the hole locations.
I drilled the brackets and tapped them for 4mm stainless screws.
Once that was done, I reassembled everything to make sure the holes lined up. The new heater core needs to be tilted a bit to fit the box since the new one is narrower than the old one and the spacing of the connections width-wise is narrower. It won't fit unless it's tilted. Don't worry about the foam sticking up. Once the rear cover is on, it compresses and forms a seal at the sides of the heater core.
Everything seems to fit pretty well.
I need to figure out a good way to seal up the box where it is circled in red below and also clean up how the foam looks. Maybe some black aluminum tape??
I'm not 100% satisfied with the foam. It seems OK, but I'd like to find some that is more resistant to tearing. If I can find that, I'll be a lot happier with this project. As it is now, the rear cover fits nice and snug once the foam is compressed and the heater core doesn't move at all when I shake the box. Next is to source some hose and elbows to feed the defrost. If you have any ideas for improvements, let me know. Thanks!
