Heater Core Observations

[Tom Mandera <tsm1@domain.elided>]

Just yanked the heater core from the '72 and the '77.  I pulled the '72 
first, and fought the factory gasket to let the core come out.  I'm going 
to use some RTV (I'm unsure what colors I have handy) to make a similar 
gasket for the reinstallation.. I noticed the remains of a gasket last 
week (or so) when I pulled the '77's core.

I yanked the '72 heater core and thought, "wow, that seems bigger.." so 
before I pulled the '77 core, I measured the height of both.. 8".  So 
they are the SAME height.. recall that the only discrepency between the 
Scout II heater cores *to-date* has been one is 1/4" taller than another.

I then yank the '77 core, and.. that looks smaller.  It's also leaking 
from the rear bottom (that is, farthest from the in/outlets, and on the 
bottom quarter).

The '77 core, IH Part # 395831-C93 marked clearly in large letters, is 
noticeably narrower.  The '77 core appears to be a 3-row, while the '72, 
I'm guessing, is a 4-row.  

The '77 has just "ribbing" on the top and bottom of the core, while on 
the '72 core, there is a gasket or plate (haven't determined which, I was 
gloved) on the top and bottom of the core, as well as the "caps" on the 
front and rear vertical sides.  Thus, with the "plate" on the top and 
bottom of the '72 core, I can't guess at how many rows, but it is very 
obviously MORE than the '77 core.

Before coming in to post the news (and make a fresh pot o' joe), I 
test-fit the '72 core into the '77 heater box.. *IT FITS*.  It is NOT too 
wide.

Unfortunately, the '72's core has smaller lettering that has partially 
faded/scraped away since it was manufactured (26+ years ago), and not 
enough remains for me to even start to give anyone a clue as to the 
entire part number.  I can't even tell which direction to read... I 
expect it to end in C93, but it looks more like C6 is in there.. which 
could be something entirely different (that is, it may not even be the 
"C" part, but maybe two different numbers)

A 3-row vs 4-row heater core could certainly explain the difference 
between the '72's blister-causing-heater and the '77s-cold-shoulder.  (OK 
OK, it was blowing hot air, but it still wasn't about to leave welts on 
my ankles)

Somewhere I heard 1980s had better heaters.. but it could've been 
confused with the full-dash 1980 A/C or something entirely different.

What I *do* know, is my '72 has a larger heater core than my '77, and my 
'72 core is going to fit right into my '77 heater box.

Could someone try to trace down what this (apparently) early Scout II 
heater core part number is - different from the 395831-C93 I found in the 
'77.  Can the Scout vendors then acquire this part for us still?  And 
anyone care to conjecture *why* IH would go from what appears to be a 
4-row to a 3-row heater core?  Sure, global warming may be lessening the 
need for *so much* heat, but really....

-Tom Mandera, Helena MT
http://www.tmcom.com/~tsm1/scout
'72 and '77 Scout IIs