Brian, you are probably right.
I looked at all types of radiators on CIK karts this past weekend and found the fins per inch on these “OEM” type factory packages are very similar to the heater core you mention. Even the small tube size is similar. What really got my attention was my Garage mate Paul putting 3 full 2″ strips of tape on his rad. Making it, theoretically, just slightly larger than mine, and only running 140 on H2O.
We drilled an additional 3 – .067 holes in the IAME inline t-stat at the track when it just wouldn’t pass any water short of running it to get the stat to open. Without the stat it was only an extra lap or 2 before it was again too hot. Restricting “flow” did not lower the max temps. A restrictive heat exchanger with a greater fin count (surface area) may just work. At this point we have nothing more to lose.
Gary Kramb uses and suggested this: https://www.carid.com/spectra-premium/heater-core-mpn-94755.html
It fits the Aerostar 86-97.
I looked hard at the rad on my bike, it looks exactly like a CIK shifter rad (high # of fins per inch) in a cross flow model. I’m seeing a pattern.
In my defense of the engine failure, I was at 45-48 gallons of fuel on the crank. A bit more than the 31 or so (120 L) recommended by the Factory. Spinning it to 15,100 didn’t help with that much time on it. It didn’t seize, it broke.
Unfortunately, I’m done with it for now. Maybe we can get Rich on one of these and get him out in October.
Thanks for looking in and giving some insight.
Brewster, I’ll put your beacon back in the box and ship it off to you. Shoot me an email with your address to be sure.