Radiator design?

[Andrew Robertson]

Hi All,

at the stage of specifying radiator design for my McLaren canam replica build, which has the same basic layout and dimensions as a 40. It will be in aluminium, and will be made by the guys at Heat Exchanger Services in Christchurch who do all my stuff and make a nice job. I'm using a Mezzeire 55GPM front mounted pump.

The drawing I got from chassis supplier Autotune in the UK is for a basic single-pass cross-flow unit 12x26, canted forward at top 20 degrees, with a -4 bleed in one top corner, and both the inlet and outlet in the bottom of the end tanks - looks a lot like the GTD unit I have seen photos of.

Given that I have a blank sheet to start from, what improvements could I make to this basic design. Should I put the inlet at the top (diagonally opposite the outlet) to make flow across the core more even? How about double pass with inlet and outlet on the same side top and bottom? If I put inlet at the top of one side could I just crack the top hose to bleed air or does it somehow accumulate in operation, necessitating a bleed ?

Thanks for your help.

Cheers, Andrew

[Terry Oxandale]

Being you're starting with a clean slate, the one thing I found most helpful is getting the mounting surfaces attached to the radiator tanks. For example, I had the fabricator weld four 3mm plates to each corner of the end-tanks to simplify the mounting process. To do this though, you'll need to know what your core support will look like ahead of time.
I also had the fabricator use 90 degree mandrel bends for the inlet/outlets to better provide the under-body clearance these CanAm cars needed (but my radiator is a 24X17 that is canted at the top at about a 60 degree angle).

[Ian Anderson]

Specify where you want the tabs fitted to line up with your desired radiator fan (s)

Ensure they are on the correct side for puler / pusher - whatever you need for the design

Also make sure you have a bung fitted for the radiator fan thermostat switch. Check the thread size of the switch you want to use - they are not all the same!

Ian

[Howard Jones]

Put bleeds on both top corners of header tanks. You will want to "y" them together externally and then run a 1/4" pipe back to the expansion tank in the engine room.

I have also run two AN3 fittings from the back of the intake water crossover ports, "Yed" them together and run a line to the front of the intake thermostat bung and then to the expansion tank.

This system will self bleed the entire coolent system and you will never need to burp the system again.

The exception might be the heater core, they tend to trap air. But if you run the heater valve full hot once in a while then it will bleed off any trapped air also.

[Terry Oxandale]

Great info. In essence, it sounds as if any and all high points in the system are eventually tied together and then connected to the expansion tank?