[LMSRACER]

This is for Information Purposes Only. These Calculations are based on a Consistent Discharge Coefficient for the Various Orifices Listed.

I've been mentioned here recently and therefore felt compelled to provide some technical information that may be of help to those interested.

I have stopped posting on this topic because, since we do make parts for pontiacs, I didn't want the Performance Years Police to punish me.

>> Here's what needs to be considered: (Initially)
1) Water Pump Flow Capacity in Gallons Per Minute.
2) Water Pump Inlet, Inside Diameter/Area.
(Should Always be Larger than the Outlet to Avoid Water Pump Cavitation.)
3) Cooling System Outlet Hose/Line Inside Diameter/Area.
(This is the Actual Orifice/Inside Diameter/Area Calculation of the Engine's Coolant Outlet.)
4) Coolant Line/Hose Routing.
(Keep in Mind that "Unrestricted" Coolant Flow Always Flows through the Path of Least Resistance.)
5) Individual Coolant Line/Hose I.D. and how it relates to the Velocity & Pressure of the Coolant.
(Actually, the I.D. of the Fitting Utilized is what's Important because the I.D. of the Fitting is Always Smaller than the I.D. of the Hose.)
6) Coolant Passage Holes/Orifices in the Cylinder Head's and Engine Block's, Deck Surfaces.
(Very Important when Adding or Plugging Holes in the Deck Surface.)

O.K., to be clear, if you are using a "Stock Block", the sizes and quantity of holes in the deck surfaces are equal to the "Approximate" flow capacity of a 1.705" Hole/Orifice.
>> Calculated from 5 x 5/16", 1 x 3/8", 3 x 7/16" and 1 x 1/2" hole per Deck Surface. <<

Therefore a "Stock Block" Deck Surface allows more than ample coolant flow and will not be the restriction to coolant flow. In fact the I.D. of a "Stock Thermostat Housing" Outlet is Approximately 1.300". That's Approximately 42% Less Flow than the Flow Capacity through both Deck Surfaces.

Here's some pertinent information relating to "AN Fitting" dimensions.
>> Necessaary for Flow Volume Calculations. <<
-8 AN = 0.390" Orifice = .11946 sq.in. Area.
-10 AN = 0.480" Orifice = .18096 sq.in. Area.
-12 AN = 0.610" Orifice = 0.29224 sq.in. Area.

Therefore:
2 x -8 AN = .23892 sq.in. Area = .5515454" Hole/Orifice (35/64" - Closest 1/64")
4 x -8 AN = .47784 sq.in. Area = .7800031" Hole/Orifice (25/32" - Closest 1/64")
2 x -10 AN = .36192 sq.in. Area = .6788305" Hole/Orifice (43/64" - Closest 1/64")
4 x -10 AN = .72384 sq.in. Area = .9600114" Hole/Orifice (31/32" - Closest 1/64")
2 x -12 AN = .58448 sq.in. Area = .86266.5" Hole/Orifice (55/64" - Closest 1/64")
4 x -12 AN = 1.16896 sq.in. Area = 1.2199862" Hole/Orifice (1-7/32" - Closest 1/64")

Therefore: (Coolant Velocity Calculations.)
>> Knowing that the Water Pump is Rated @ 30 Gallons Per Minute in this Example. <<
2 x -8 AN Fittings = 40.281 ft./sec.
4 x -8 AN Fittings = 20.141 ft./sec.
2 x -10 AN Fittings = 26.592 ft./sec.
4 x -10 AN Fittings = 13.296 ft./sec.
2 x -12 AN Fittings = 16.466 ft./sec.
4 x -12 AN Fittings = 8.233 ft./sec.

O.K., So here's what you need to consider:
1) As the velocity in the Hoses/Lines Increases, the Positive Pressure Created by the Water Pump in the Engine's Coolant Passages also Increases.
2) Positive Pressure in the Engine's Coolant Passages that is Created by the Water Pump is a "Good Thing". Not at all the same thing as "Coolant System Pressure" created by Engine Heat or by the Formation of Steam Pockets.
* NOTE: "Excessive" Positive Pressure slows the Water Pump and can Actually Damage the Pump's Electric Motor.
3) Whenever the Water Pump is Capable of Creating a "Positive Presure" in the Engine's Coolant Passages, it is of Benefit. The Idea is that the Coolant Passages are full of Pockets and Cavities that can be Difficult for the Coolant to Reach and for the Air to Escape. These pockets are Steam Traps. Temperatures in Steam Pockets Sky Rocket and can be Disasterous. The Positive Pressure Created by the Water Pump Aids in Forcing Coolant into these Areas and Forcing the Air out.
4) Never Run the Engine without the Water Pump Running. Once a Steam Pocket begins to Form it Pressurizes that Area and it then becomes very difficult to Quench that Area once the Water Pump begins to Run. Picture what happens when you pour cold water into a Hot "Cast Iron" Skillet. Now picture that same water cooling the skillet before it gets hot. One way it cools the skillet easily and the other way it's a losing battle.
5) Fabricate and Install Coolant Lines from the Rear of the Cylinder Head Outlets at the Intake Flange Surface (Factory Heater Hose Outlet Area.) to the Thermostat/Water Outlet Housing Area. Preferrably above the Restrictor that you would run in place of the Thermostat. The Restrictor's Size should be Utilized to Control the Flow of Coolant from the Front of the Engine Only.
>> If you haven't already done this, you should. <<
6) If your Engine is a "Serious Race Effort" then adding additional lines from the Center of the Heads, at the Intake Flange Area, to the Thermostat/Water Outlet Housing Area is also a must.
>> If your Heads don't have the Outlets already, then add them. <<
7) In Extreme Effort Applications, some folks, such as Scott Rex, John Langer and John Marcella are actually "Injecting Cold Coolant" through the Cylinder Head and onto the Deck Surface between the Center Two Exhaust Ports to keep the Head from getting Soft and Warping.

Here's where it gets tricky. Everyone asks, What Size Lines and How Many?
The answer relates to the Water Pump Flow, the Engine's Power Output, the Fuel being Utilized and the Plumbing Configuration.

Here's some "Basic Recommendations":
1) Belt Driven Pumps and Mechanical Pumps with the Moroso Water Pump Drive.
>> Bare Minimum = 4 x -8AN Hoses. Two from the Front and Two from the Rear. <<
(This Calculated Volume is Slightly Greater than Running a Single 3/4" Restrictor in Place of the Thermostat.)
2) 30 GPM Electric Pumps.
>> Most Racing Applications = 4 x -10 AN Hoses. Two from the Front and Two from the Rear.
(This Calculated Volume is Slightly Less than Running a Single 1" Restrictor in Place of the Thermostat.)
>> Optional = 2 x -10 AN Hoses Front. 2 x -10 AN Hoses from the Rear coming off of a "Y" Fitting where Two -8 AN Hoses are Plumbed to the Rear of the Heads and 2 x -6 AN Hoses are Plumbed to the Center of the Heads.
3) Inline Water Pumps and High Volume Electric Pumps above 30 G.P.M..
>> Three -10 AN Lines Per Cylinder Head for a Total of Six. These Six Lines Plumbed into a Coolant/Water Outlet Manifold like the One Offered by John Marcella and CSR to just Name a Couple.
4) Extreme Effort Applications = Whatever it Takes... LOL.....

For the Guys looking to keep a more "Stock Appearance", Reduce the Number of Coolant Lines and keep their Cost down, we offer components that can maintain the factory water crossover manifold in the front of the engine and the factory water outlet/thermostat housing. They're engineered so that the flow volumes are correct and the appearance is much more factory without so many hoses, fittings and exotic fabricated manifolds. They're also designed to control the coolant flow from the front and rear of the engine seperately, much the way that varying the individual hose sizes does.

One Last Note:
Configurations differ and although alot are the same, some can be exotic. I can help you with your set-up if you want me to. Shoot me a PM or an E-Mail @ oprecisionautom@carolina.rr.com...

Thanks for Listening.. Back to Work,
Larry S.

[LMSRACER]

This product is for applications that will utilize center outlet coolant hoses in the cylinder heads.

We are currently in the production phase of a "3-Way" fitting/manifold that will eliminate the need for a standard AN "T" fitting and the three "Hose End" fittings per cylinder head that's required for merging the center outlet coolant hoses with the rear coolant hoses that make their way to the front of the engine.

Multiple Hose Fittings are not only Bulky, but Expensive Too. Plumbing "T" fittings under the Intake Manifold requires the use of Six Hose End Fittings in all. That's Unsightly, Expensive, Difficult to Assemble and Bulky.

What we are going to offer is a "3-Way Manifold" (NOT A "T") with smoothly merging internal passages. This manifold will use "Push Lock" Hose which will eliminate four of the six hose ends. The cost will be a fraction of the cost of AN Hose and Fittings. It will also occupy much less space under the intake manifold.

We're going to offer complete kits for a variety of applications. Until now we've only offered individual components and free advice. The rest has been up to the customer.

It's all coming soon...........

Thanks Again,
Larry S.

[Tom Vaught]

Great Post Larry S, Thanks very much for the cooling info.

Tom Vaught

[BruceWilkie]

Thanks for posting and sharing the info Larry.

fwiw... the water pump outlets on the early 55-59 reverse cool timing cover measure @ 1.095" ID(0.94 sq in)... as does the entrance to the gusher tube.

This link http://www.pontiacsafari.com/Engine Cooling/index.htm gives great insight to both the original 55-59 reverse cool scheme AND shows what changed in 1960. Take note of the deck drilling differences and the timing cover to block coolant holes. On early system very little water flowed from block to pump... large majority went from pump to the cylinder heads and back to the radiator.

Early system was a better cooling scheme but more complicated(likely cost more) and created an obstacle for lower mounting position of accessories... a consideration of lower hood lines in the future... the convential cool scheme of 1960 and newer was deemed adequate for anticipated "normal" use of the vehicle and warranty. requirements. No doubt to me that the "bean counters" won that one!

BTW... the gusher tube is an engineering marvel in all that it does. Unfortunately newer heads cant accomodate it... However a 9 port cooling rail(water manifold) could be fabbed and plumbed just below the valve cover rail. One port for each valve guide and the center port to the center ex side head bolt area. 9 tubes @ 3/8" id each tube is @ same flow area as pump outlet. Keep in mind on early factory system the block to timing cover water holes are only @ 1/2" and in the factory scheme serve same purpose as the thermostat bypass on 60-up systems. Useful info if you want to reverse cool a Pontiac. Cool cylinder heads help make more power.

[demonic68]

Thanks for the post it very helpful

[LMSRACER]

First Off, Thanks Guys, I'm glad to Help....

Check out what I did to a 400 Chevy Dart Block Engine. This is for a Street Car and uses a Thermostat. A Dart Block doesn't have a Thermostat Bypass Passage. So, I used the Heater Core as the Thermostat Bypass.

The Silver Fitting that the Heater Hose slips over on the Intake Manifold has a Calibrated Restrictor inside to Control the Volume of Coolant that Bypasses the Thermostat.

Too much Volume through the Heater Core will cause the Engine to Run Hot. The reason is that the coolant that bypasses the thermostat also doesn't make its way through the radiator.

I did this to promote coolant circulation throughout all of the coolant passages whether or not the thermostat is open.

BTW, I did this in steel line because going the "Hoses and Fittings Route" was just too big to clear everything, such as the Vacuum Advance Canister and the Fuel Log.





It's not very noticeable now that it's installed in the vehicle.

It's been in the car for two years now.......

Thanks,
Larry S.

[Dave Polichena]

Good info Larry!

Not sure if this has been asked and may be a stoopid question, have you or anyone drilled in the center on the intake side in a HiPort? I've seen eheads and tigers done.

[LMSRACER]

Originally Posted by Dave Polichena

Good info Larry!

Not sure if this has been asked and may be a stoopid question, have you or anyone drilled in the center on the intake side in a HiPort? I've seen eheads and tigers done.

Hey Dave,
No I haven't. Although if you wanted me to I would. What I mean to say is that if you feel uncomfortable doing it, send the heads to me and if it can be done I'll do it for you and guarantee that it will be good to go. I'll do the Intake Manifold Flanges too if you'd like.

Although, I feel sure that someone here has done it and will elaborate on the process.

Thanks for asking...

BTW, for the Guys here with High Output "Street Cars", I'm working on a "Y" Manifold, Hoses and Fittings in a Kit to Allow Plumbing both Heads to the Heater Core instead of just the P.Side Cylinder Head. I plan to design it so that the Thermostat is retained and so that the flow of coolant through the heater core will not be excessive.

As most probably already know, the factory fitting in the P.Side cylinder head actually has a restrictor built into it. (In Most Cases.)

Therefore, the actual flow through the heater core is much less than what the Inside Diameter of a 5/8" heater hose fitting would indicate. So when you design fittings from both cylinder heads to flow coolant through the heater core it's important to consider the "Combined/Total Volume" of coolant that is flowing through the heater core and therefore bypassing the radiator.

Keep in mind that bypassing the radiator with a small volume of coolant reduces the overall "Cooling Efficiency" of the cooling system to a small extent. Although the benefit comes from the improvement of coolant circulation through the entire cooling system at "All Times". The reduction and/or elimination of steam pockets and trapped air along with a more consistent coolant temperature throughout the engine is where the benefit is.

Thanks,
Larry S.

[slowbird]

Originally Posted by Dave Polichena

Good info Larry!

Not sure if this has been asked and may be a stoopid question, have you or anyone drilled in the center on the intake side in a HiPort? I've seen eheads and tigers done.

There is no problem doing it. Pics of my test head where I did it

[Chupa]

What pressure is the optimal pressure?

Isn't all this dependent on the pump volume for a given pressure? Typically pumps are rated at free flow; which doesn't help us much.


Anyone have pics of installing a 3/8 npt port on the center of edelbrock heads that have an exhaust crossover? Trim this section of the intake off? Pics?

I was planning on -8 from rear, center then installing drilled plugs in the front to balance flow and run it all through the water crossover.

[LMSRACER]

Originally Posted by slowbird

There is no problem doing it. Pics of my test head where I did it

Good God that Casting is thick..... Thanks for sharing that.....

Anyone that wants to drill this passage in any cylinder head has to do some basic measurements before drilling.
1) Measure the distance from the deck surface of the cylinder head to the highest point in the coolant passage (Inside the Cylinder Head.) where you intend to drill.
2) Determine the size of the threaded hole that you want to have and divide that hole size by two (2).
>> This is not the same size as the drill size if you're threading the hole for a NPT Pipe Thread. <<
3) Subtract meaurement number 1 by measurement number 2.
4) Measure from the deck surface up to this point (The answer to #3.) on the outside of the intake flange and mark this point for drilling.
5) This point is usually an equal distance from the front coolant outlet passage and the rear coolant outlet passage along the intake flange surface.

Larry S.

[LMSRACER]

Originally Posted by Chupa

What pressure is the optimal pressure?

Isn't all this dependent on the pump volume for a given pressure? Typically pumps are rated at free flow; which doesn't help us much.

Anyone have pics of installing a 3/8 npt port on the center of edelbrock heads that have an exhaust crossover? Trim this section of the intake off? Pics?

I was planning on -8 from rear, center then installing drilled plugs in the front to balance flow and run it all through the water crossover.

You are correct.. Determining any "Water Pumps" Volume at a given pressure is not something that you'll find published. What you can determine is whether or not the sizing and quantity of your coolant lines or manifolds actually exceed the rated volume output of your pump. If the lines or manifolds installed have a greater volume capacity than the rated water pump volume then there will be no chance of developing a positive pressure in your engine's cooling system. Also, the velocity of the coolant in the lines that you install CAN be determined and for that there definitely is a range of acceptance.

Here's a good example....
Let's say that you start installing fittings and hoses and restrictors and such. Then you plumb them all together in the water crossover. Let's say that the capacity of your pump is such that the velocity becomes slow and therefore the pressure of the coolant becomes very low. What's to say that the coolant would ever actually flow to the "Rear Most" portions of your coolant passages? Let alone aid in evacuating trapped air or quenching "ALL" of the internal coolant passages.

In my original post I say "APPROXIMATE" alot. The reason for that is that determining the Discharge Coefficient of a "Block Passage" or a "Cylinder Head Passage" is difficult if not impossible. (Discharge Coefficient Calculation for a Crusty Passage, NOT Likely.)

Determining the Discarge Coefficient of a "Nozzle" or a "Sharp Edged Orifice" like the restrictor that replaces the Thermostat is much easier to calculate.

My intention here is that, I want people to take a minute to think about their cooling systems and how they actually operate and not just start installing hoses, throwing in a restrictor in place of the thermostat and calling it good.

Thanks,
Larry S.

[Dave Polichena]

Originally Posted by slowbird

There is no problem doing it. Pics of my test head where I did it

Thanks for sharing, next time it comes apart I think I will be doing this, hopefully that won't be for a while Do you feel that the height of that hole is sufficient enough, first thought would be to lower it down a little.

[Dave Polichena]

[QUOTE=LMSRACER;5153359]Hey Dave,
No I haven't. Although if you wanted me to I would. What I mean to say is that if you feel uncomfortable doing it, send the heads to me and if it can be done I'll do it for you and guarantee that it will be good to go. I'll do the Intake Manifold Flanges too if you'd like.
QUOTE]

Thanks Larry but after looking at Brians pics, I think I should be able to handle it.

[jm455ho]

Debating with myself whether to do the middle hole on my High Ports. Strictly race, 12:1 compression, and around 750 HP. Not sure the benefits merit the extra complexity of fittings and hose at that level. I am presently set up to pull water from front and back holes only. Engine is not assembled yet, so now would be the time if I decide to do it.

[LMSRACER]

Originally Posted by jm455ho

Debating with myself whether to do the middle hole on my High Ports. Strictly race, 12:1 compression, and around 750 HP. Not sure the benefits merit the extra complexity of fittings and hose at that level. I am presently set up to pull water from front and back holes only. Engine is not assembled yet, so now would be the time if I decide to do it.

Assuming that you're running a stock block, stock deck arrangement here's my opinion. Do It.....

Here's why I feel that way. Every pontiac engine that I've ever built and raced always showed signs of excessive heat between the center two cylinders. Some more than others. I feel that by offering the coolant a path out of the cylinder head in the center promotes alot of additional coolant flow from the engine block, through the deck, around the center two exhaust ports and out through the fittings.

Otherwise the coolant is pumped into the engine block, then around the cylinders, through the deck at the path of least resistance and out through the water crossover manifold or a combination of the water crossover manifold and the two hoses running from the rear outlets.

Without the center two hoses who's to say that the coolant flows readily around the center two exhaust ports where the greatest heat is generated.

I don't think that you need to run large lines fron the center of the heads. You could just run some -6 lines from the center to ensure that coolant flows readily in that area.

I also believe in drilling the additional coolant hole in the deck surface of the engine block and the cylinder head just above the lower head bolt/stud between the center two exhaust ports. Once again, as stated earlier, I don't know if that hole can be drilled in a KRE High Port Head.

Just My

Larry S.

[jm455ho]

Running an aftermarket block (IAII). My Cometic gaskets don't have the addition cooling hole, so I can't add it (and as you stated, not sure if you can on HP heads). I am leaning towards adding the holes.
Thank you for your comments, very helpful.

[jm455ho]

I am thinking 2 #10 lines out the front, 2 #8 lines out the back and 2 #6 lines out the center.

[LMSRACER]

Originally Posted by jm455ho

I am thinking 2 #10 lines out the front, 2 #8 lines out the back and 2 #6 lines out the center.

What Water Pump are you using?
Did you drill the deck surface of the block to match the coolant passages in the KRE HP Heads?
What type of coolant manifold are you going to use at the front of the engine?
What size line are you going to run back to the radiator?

Larry S.

[jm455ho]

Meziere electric pump. Holes were drilled to match Cometic gaskets as supplied by Jim Robertson. Haven't checked the holes on the HP's as previously the engine was built with KRE D ports. I have a water manifold in the front from Marcella. I will measure all hole diameters and get back to you. Thanks again for your help.