Aluminum Radiator

I have not needed additional cooling since I moved to Oregon, but I had this nice prototype radiator I had built some years back and finally decide to make the upgrade.

The Ron Davis Vehicross aluminum radiator was copied from an after market stock radiator supplied to Ron Davis Racing. The build sheet is 5225, for reference.

The core thickness is increased to 2". (Like a 4 tube copper core)

The plan was to omit the stock clutch fan. A dual fan shroud was fabricated. An electric dual fan controller must be added. Two different diameter and thickness fans are used to fit side by side and maximize the fan cross section. By chance, the larger fan diameter, with a deeper larger motor, was located on the driver side. This conflicts with my S/C idler pulley and belt path. Without the S/C, it might fit. We rotated the shroud 180 degrees and put the smaller thinner fan opposite the S/C idler pulley and it just touched. Still no good.
If the stock fan is removed, ¼” spacers must be used on the four fan studs with nuts, since the studs are not fully threaded. The studs hold on the water pump drive pulley.

My installation cannot use the new fan shroud and electric fans until the shroud is modified to reduce the overall thickness.
In the end, the stock fan was used without any shroud. This is not the best. The stock, or any fan, will pull air from the easiest direction, which is not through the radiator. A shroud forces the fan to pull air through the fins.

Two threaded holes in the top of the tank (Facing up) are used for a hold down bracket. A proper bracket must still be fabricated

The current bracket uses the one of the stick radiator frame holes nearest the radiator and one of the two holes on the top of the radiator. A rubber “Snapper” vibration mount is snapped around the new bracket. This is a muffler attachment part.

Car Prep-
Cut off two small screw ends on the right and left of the radiator. They are about 3” down from the top. Use an abrasive wheel. These screw ends would rub on the radiator front side edges.

Remove the adhesive taped rubber strips on the radiator cross frame at the top. Re-tape and replace after the installation. This spaces the radiator from touching the steel frame.

Dent the hood liner, if required, to clear the radiator cap. The revised design will have a 1/4" lower neck than my prototype.

I used two new rubber-mounting biscuits at the bottom. The 10-year-old biscuits were still soft, so replacements are not needed.

Use a ¼” nylon wire retainer on the OEM trans fluid pipe as it crosses the bottom radiator tank. A bolt boss is provided.

The wire bundles on both sides, low near the radiator, must be pulled to the side to clear.

On the passenger side, an unused bracket, low next to the radiator, is removed with two bolts. This is next to the lower hose tube.

The top and bottom radiator hoses must be shortened (Cut back) about ½” to ¾” due to the thicker core. If not, the hose is pushed against the engine.

Inspect for any contact points after installation. Aluminum is soft.

Install the stock plastic fan shroud if using the stock fan. I will use aluminum metal duct tape to attach the vertical edges of the plastic fan shroud to the radiator. The stock shroud assembles from top and bottom parts. The Ron Davis redesign will have threaded bosses in a position to bolt on the plastic shroud in two places on the top and have slots in two places at the bottom. These mounting points are the same for the aluminum shroud.



Required Mods to the Ron Davis Radiator Prototype -

Lower the fill neck ¼” or more. The cap ear hits the hood and requires a dent in the hood liner to clear.

The driver’s side auto trans fitting is currently (Original RD design) a M14x1.00. This is wrong and not OEM. The after market radiator used for a fabrication model had a non-OEM fitting and got copied incorrectly. The correct male threaded fitting with flair bevel, is an M14x1.50. This fitting is required to mate to the OEM brass fitting and 90 degree tube that routes the trans fluid inlet next to the outlet. (Both are hose barbed) The trans fluid outlet is an SAE ¼ female pipe thread boss on the passenger side. Ron Davis supplies an aluminum ¼ male pipe to ¼ hose barb fitting for this attachment.

The RD fan shroud attaches to the top of the radiator tank using two threaded bosses. If the driver side boss is moved 2 1/8” toward the outside of the radiator (A center to center distance between the bosses of 13 ¾”), the stock plastic fan shroud will bolt on, if an electric fan shroud is not used. The passenger side boss is correctly positioned.

The bottom mount for the fan shroud is by two slotted brackets on the radiator bottom tank. These brackets are positioned to accept the stock plastic lower fan shroud tabs without any change.

If you are ordering a Ron Davis Vehicross radiator, verify that the changes I have described here are included the design drawings. Communications sometimes break down. Trust but verify. (Ronald Regan)

I will add some photos shortly.

Roy