radiator questions

[oldways]

Gday everyone.... I am building an Austin Healey replica. Here is the problem I don't have enough room for the radiator (from the donor car ford sierra) if I mount it vertically. So my question is how far off vertical can I go that it will still function properly? I am using a v6 motor... the other possibility is to try a smaller radiator but how can I calculate the size of radiator i need to cool the engine. I also need to know the importance of relationship with the lower radiator outlet of the radiator to the water pump (the water pump is on the water input to the motor)

[rspears]

G'day! My radiator on the '33 is tilted back right at 20degrees. Because of the clearance with the engine I'm running an electric puller fan on the back side, but would rather it be a straight mechanical drive fan. The biggest thing I see there would be that the fan shroud is going to need to be made to extend back for proper flow. With a custom shroud there's no problem with tilting - just look at the Shelby Cobra for an example.
You want the lower radiator outlet to be on the same side of the engine as the water pump inlet, as much for ease of routing as anything, and be sure that your lower hose has an internal spring to prevent it sucking shut at high flow.
Easiest way to determine your radiator need is to look at the OEM radiator for the donor vehicle for area and number of row reference as a starting point, and don't go smaller, IMO.

[lakeroadster]

To expand a bit on Roger's comments, the fan shroud needs to cover the entire back of the radiator. This ensures the full radiator area gets air drawn through it. When the radiator is tilted the fins tend to block natural air flow. Additionally creating panels to fit between the grill shell and the radiator will also help to ensure the air goes through the radiator, and not spill over, under or around the sides of it.

As for sizing, perhaps the wise thing to do would be to contact a manufacturer, such as Walker Radiator, and ask them to size a radiator based on the engine you will be using. Then you will know 3 core vs. 4 core, etc. They make a living do this, see if you can get their recommendations.

Hope this helps!

[daveS53]

The radiator in my Oze tilts back at about 24 degrees and it works fine. Mine came with the shroud and a SPAL fan, from Performance Rod & Custom. The fan seems quite noisy to me, but only runs when I'm idling at a stop light.

Aluminum Custom Built Radiators | Street Rods, Classic Cars, Muscle Cars, Trucks

[chopt50wgn]

Rule of thumb for finned area of radiator is determined by cubic inch of the motor. Example........if a motor is 400 cu.in. then radiator should be 20"x20".
Now this is not set in stone but used as a reference. HP is a biggie as well. More HP= more heat. Tube width inside radiator can also be a big help. Aluminum rads usually start at 2 rows of 1" tube. I have seen custom cores made that are one row of 1.50" . So there are choices if you look into things.

[oldways]

Thanx everyone for your help i think i now have the confidence to take it from here...!