Quote:
Originally Posted by LMSRACER
Thanks Don, I Appreciate that..
I get alot of E-Mails and Calls about this subject so I thought that I'd post some information here........
Here's my thoughts on Reverse Flow Cooling a Dry Deck Block...
I'll give two options depending on the flow volume of the water pump to be used...
Option #1 Flows ALOT of Coolant through the Cylinder Heads...
Option #1: 55 GPM External Pump. (Outlined In Order of Flow Direction...)
1) Two -16 AN Outlets at the Pump.
2) Two Fabricated Coolant Manifolds, each with a -16 AN Inlet and Two -12 AN Outlets.
3) Two -12 AN Inlets in Each Cylinder Head. One in the Front and One in the Center.
4) One -16 AN Outlet at the Rear of Each Cyliner Head.
5) One -16 AN Inlet at the Rear of Each Cylinder Bank of the Block.
6) One -20 AN "Final" Block Outlet/Radiator Inlet at the Front of the Engine.
(A 1" Inside Diameter Slip On Hose Fitting or Restrictor would also work fine.)
Option #1 is tough to do because of the size of the lines and packaging/fitting all of that around the intake manifold and rear of the block. A "Front Drive Distributor" and a Belt Drive System makes it much easier to accomplish.
Option #2: 40 GPM External Pump. (Outlined In Order of Flow Direction...)
1) Two -12 AN Outlets at the Pump.
2) Two Fabricated Coolant Manifolds, each with a -12 AN Inlet and Two -10 AN Outlets.
3) Two -10 AN Inlets in Each Cylinder Head. One in the Front and One in the Center.
4) One -12 AN Outlet at the Rear of Each Cylinder Head.
5) One -12 AN Inlet at the Rear of Each Cylinder Bank of the Block.
6) One -16 AN "Final" Block Outlet/Radiator Inlet at the Front of the Engine.
(A 13/16" <0.8125"> or 27/32" <0.84375"> Inside Diameter Restrictor or Slip On Hose Fitting would also work fine.)
Let me make a Notation about Hose Fittings and their Dimensions.
The flow volume from one fitting size to the next, for example a -8 to a -10, changes greatly. At first glance a -8 to a -10 is a 25% increase in flow.
That is incorrect, it's actually a 51.48% increase.
From a -10 to a -12 is a 61.5% increase in flow.
From a -12 to a -16 is a 89.62% increase in flow.
From a -16 to a -20 is a 65.3% increase in flow.
So, whenever you design your cooling system for flow volumes and pressure, there's always going to be a certain amount of "Close Enough" or an "As Good as it's going to get" going on. Unless you "Engineer" ALL of your own fitting and hose dimensions, you'll be confined to working with what is available in the industry.
Just keep in mind that you want the water pump to create a "Positive" cooling system pressure in the heads and in the block. If you size your system's hoses and passages too large, the water pump will never create a positive pressure. Where that positive pressure is located depends on where the restriction is located in your system. Remember that greater restrictions (Smaller Orifices) increase the system pressure and decrease the flow volume and reduced restrictions (Larger Orifices) decrease the system pressure and increase the flow volume.
When using an Externally Mounted Water Pump, make sure that the pump's outlet lines are large enough that they don't restrict the coolant flow at all. Creating a Positive Pressure in the Water Pumps Outlet Lines before they ever reach the Engine not only Reduces the Water Pump's Outlet Volume, it puts an unnecessary strain on the pump motor.
One Last Note:
All of the Fiiting Dimensions that I've used for Calculation are Published Aeroquip Dimensions. Others may vary somewhat...
Thanks Again,
Larry S.
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These approaches should work quite well...
Heres my planned layout...
I'm using a 59 timing cover and pump so I think I will have flow and pressure enough(yeah its heavy but trying to add a nostalgic look to this yet modern too, as I'm running serpentine belt system)...
I did some test drilling on a scrap 6x along the valve cover rail... I've decided it would be beneficial to mimic the "sprinkler" tubes of the early heads. They directed coolant to the valve guide areas and exhaust ports before flowing back across head to the crossover.
New style heads cannot accommodate the internal tube so instead of just 3 inlets like you propose I'll have NINE!...
One for each valve and one in front and above the center ex bolt boss. I drilled as close as I felt comfortable to the exhaust ports/valve area and the drillings for the intake valve areas are pretty much in line... center hole at bolt boss had just enough room to clear boss and not interfere with valve cover. All the holes are slightly angled to avoid valve cover interference. The holes are just below the valve cover rail.
Nine 1/2" holes that accommodate tubes 1/2" od with 3/8" id... total area @ same as water pump outlets. These 9 tubes will go into a rail type manifold(same concept as efi rail) with same inlet ID as pump outlet.
Water can exit at head ends on manifold face...
Its crowded by the distributor and plumbing to those rear holes on the manifold face of the heads can be challenging...however the manifold flange can be extended(welding) with a block of aluminum to cover the hole then drilled/tapped at a more favorable angle.
Due to my timing cover design, dry deck cooling through block might best be done by entering from the side just below the center head bolt boss and exit out the ends with coolant fed to inlet from a separate remote pump.
Keep in mind the heads need far more cooling capability than the block does, but coolant entering at center bolt boss can only help IMO
However... I think with a bit of creativity I can run wet deck with very low risk of water in cylinders should a head gasket fail. Small counterbores around coolant holes in deck and head, with nylon or metal o-rings and "Right-Stuff" sealant would likely be near bomb proof. That sealant would allow enough stretch for amount of lift the heads might see at high power. (
I "glued" a rubber cap on a 1/2" pipe with Right-Stuff and at @ 100 psi the cap remained on the tube. NO clamp!)
A lot of extra work...probably way overkill... but keep in mind, mine is a twin turbo build and intention is to be able to drive most anywhere and race.(Drag week...perhaps! Drive to Norwalk from TN, race and then drive back? Thats main goal!)