[TR] Aluminum radiators

[Randall]

> 1) Use the current radiator, and don't go on the race track

I would definitely not take that option!  My radiator shop said my TR3 radiator "flowed fine" and yet I had persistent overheating problems during just normal highway driving that proved to be caused by crud buildup inside the tubes.  None of the tubes were blocked, but the crud was acting like an insulator and reducing the essential heat flow.

This is not my first experience with cooling issues caused by invisible radiator problems.  The previous TR3A had very similar symptoms (temp would creep up at freeway speeds even with just 70F air), and recoring the radiator immediately solved them entirely.

> I know that if I use the radiator with the starter hole that
> I lose something like 5% of my cooling, 

More like 10-15% according to my radiator guy.  All of the tubes that would normally go through the space occupied by the crank hole are totally blocked off, so they do nearly nothing as far as cooling.  You lose not just the open space of the hole, but a section that wide of the entire height of the radiator.

Another option is to have your original radiator re-cored.  I'm told that Modine no longer makes the core I got in the 3A, but there is another company that will make radiator cores to order (and they have the specification to fit the TR3).  You can even keep the crank hole if you choose (although I didn't).  Your local radiator shop should be able to handle ordering the core and installing it for you.

I am very happy with my recored radiator and electric fan.  The engine stays cool under all conditions, even during autocrossing or sustained full throttle operation; and the fan only runs for a few seconds at idle or stop-n-go before the water coming back from the radiator drops below 190F (the setpoint I chose).  I also had the shop change the filler neck to take a modern cap, so I could add a recovery bottle.

In retrospect, I kind of wish that I had tried putting back the stock mechanical fan with the recored radiator, as I suspect that might have worked as well.  But for now at least, I have no intentions of going back.

Randall