Bottom Line

The cooling system in this 1934 Pro Street Sedan with its 502/502 Chevy Big Block keeps the coolant temperature at 180 to 185 degrees even in very hot weather with the air conditioning running - - as long as the car is moving at any speed.  The details of the cooling system are provided below. 

The biggest challenge was handling the cooling chores when idling on very hot days.  Technical details of how that was solved are provided on additional Web Pages for which the Links are provided at the bottom of this page.  The most significant fix and also the most subtle, was ignition timing and the use of "Manifold Vacuum" versus "Ported Vacuum" to supply the distributor vacuum advance diaphragm.  Go to the bottom of this page and/or Click On this Link Most Important - - -Ignition Timing  to find out  how that solution was implemented.

Radiator

This 1934 Street Rod with a 502/502 Chevy Big Block uses an aluminum radiator from Griffin.  Aluminum is lighter than copper  (in actuality copper fins /brass tubes ) but has lower heat transfer.  However aluminum tubes can be made in a thin wall, efficient, long oval shape to produce an excellent radiator.  The fins can be joined to the tubes with no reduction in heat transfer unlike the lead solder which reduces heat transfer between the copper fins and brass tubes. The following is a quote from the Griffin Q&A Web page:

"Does an aluminum radiator cool better than a copper brass radiator?
An aluminum radiator does cool better than a copper brass radiator. For example, an aluminum radiator with 2 rows of 1" tubes is equivalent to a copper brass radiator with 5 rows of 1/2" tubes. Aluminum provides high efficiency, is lightweight, and has a longer life compared to copper brass."

This Griffin radiator uses two rows of 1 inch tubes one behind the other.  Griffin also makes a thicker radiators with two rows of 1 1/4 inch or 1 1/2 inch tubes.  Considering there is currently just  enough room for the air-conditioning condenser and electric fans stuffed between the radiator and the grill, this size was the only option! Also since cooling is excellent while the car is moving at any speed, a thicker radiator would not be useful. This Griffin radiator has a reserve tank built into the top tank.  As the coolant expands it goes into the reservoir then returns when it cools.  Pretty trick, no extra external container needed!  Although the Griffin radiator comes with connections in the lower tank for cooling the transmission, A separate auxiliary B&M high efficiency trans cooler was used instead. This reduces the heat load on the  radiator. The car operates at the thermostat setting of 180 degrees when it is moving at any speed. Even on a 95 deg. day it may go to 185 with the air-conditioning on.  The only difficulty is when idling in hot summer days.  The following describes what features help reduce the temperature under those conditions:

Radiator Shroud

A Griffin aluminum fan shroud is used (See the photo on top of this page).  Ideally one should have the fan and opening at the top of the radiator.  That is where the incoming coolant is the hottest and the air movement across the radiator in that area will have the maximum cooling effect.  Unfortunately motor and fan position are dictated by other considerations.  The fan shroud comes blank and the opening was cut where the fan intersected.  The shroud does help pull air from all over the radiator including the upper portion.  Be sure there are no gaps between the shroud and the radiator for air to bypass going through the core.

FANS

The mechanical fan is the maximum size that would fit.  It is 15 inches in diameter and has 6  high pitch aluminum blades for maximum air movement.  If the car did not have air conditioning that may have been enough.  However a Vintage Air Super Flow Condenser covers most of the front of the radiator.  To provide improved cooling when idling, two Perma-Cool electric fans are mounted as "pushers" to the Condenser in front of the radiator.  The maximum sizes that would fit were an 8 inch (2 1/4 inch deep) 800 CFM up top and a 10 inch (2 1/4 inch deep) 900 CFM under it. You can see parts of each fan behind the grill bars in the photo on the left.  They are connected electrically  using a high current relay near the radiator to a thermostat in the lower radiator tank (Griffin supplies a threaded hole for such an installation.)  A switch on the dash is connected in parallel  so when  in stop and go traffic the fans can be turned on manually before the temperature starts to rise!  The 140 amp alternator (95 amps at idle) sure comes in handy when both fans are on!  The upper fan forces air through the hottest part of the radiator which, as mentioned above, provides the most effective heat transfer.  On all but 95 degree plus days you can watch the temperature reduce when the fans are energized.

The combination of a high pitch mechanical fan with two electrical fans provide the needed air flow to keep temperatures at the thermostat setting of 180 to 185 degrees except when idling on the  hottest summer days.

MIG Gas Delivery and the Small Block Chevy Evolved in a Similar Way and Time!

 Both had Advances and Setbacks Before

They Were Optimized!