My Cooling Improvement Project (hopefully)

["Dart67"]

This will be a long post by the time I am done.

I have been trying to resolve a cooling problem with my 512 EFI "Home-Brewed" Dart GT convertible for some time now.
I started this project late last summer.
The project was put on hold while I recovered from Left Total Hip Replacement.
I am now about to finish up.
The following is what I have changed, added, made or upgraded to hopefully improve or resolve the cooling issues.

CHAPTER 1 - The Water pump
After reading the water pump test results in this thread Overheating issue resolved....interesting read !
I decide to change from the Edelbrock pump (Pump 2 in the test) to a MOPAR Performance 8 blade impeller pump with the addition of a cavitation plate.
I made a cavitation plate from sheet metal and welded it to the back side of the impellers.
Here are a few photos of the water pump before and after the addition of the cavitation plate.

 

["Dart67"]

CHAPTER 2 - Crank and Water pump Pulleys
The next thing I changed was the crank and water pump pulleys.
I did this to try to get back as close as possible to the factory pulley ratios.
According to the information on this site:
http://www.bouchillonperformance.com/BPEpulleys.asp
The factory single groove crank pulley is 6 9/16" and the single groove water pump pulley is 6 7/8".
This is a pulley ratio of .95 to 1.
With a crankshaft speed of 1000 RPM the water pump RPM is 1047.62.
The pulleys I had on the engine were:
Crank Pulley Diameter = 6 7/8" or 6.875" and Water Pump Pulley Diameter = 4 3/4" or 4.75"
This combination has a Pulley Ratio of .69 to 1 or a water pump speed of 1447 RPM.

I THINK the water pump speed was too high and not allowing the coolant to stay in the radiator long enough.
I had spare crank and water pump pulleys that are both 5 7/8" which is a 1 to 1 ratio.
At a crank RPM of 1000 the water pump will be 1000 RPM or about 47 RPM slower than stock. I am hoping that slowing the coolant flow thru the system will help lower the engine temps.

 

["Dart67"]

CHAPTER 3 - Heater Hoses
I had my heater hoses routed down and to the rear between the block and headers. I think they were also picking up heat from the block and most of all the headers.
If you look at the first pulley photo above, you will see how the hoses were run.
I have made up "pass thru" fittings and ran the heater hose thru the frame rail and into the passenger side front wheel well to try to remove any heat from the engine bay.
Sorry, I did not get any photos of the brass fittings that I made. What I did was to get two 5/8" brass flare fittings and two 4" X 3/8" brass nipples.
I used a 3/8"NPT tap and treaded the inside of the flare fittings. Then I cut and retheaded the nipples to the required length and assembled the flare fittings on to the brass nipples and silver soldered them together.
With the brass fittings thru the frame rail, I added 3/8" black iron 90* elbows and black iron nipples. I cut 6" x 3/8" black iron nipples in half, then turned groove with my metal lathe to help hold the 5/8" heater hose.

See the following photos.

 

["Dart67"]

Chapter 4 - Radiator
Now to the big part of the project.
I ordered a 26" 67 Charger aluminum radiator from Wizard Cooling and had it upgraded to 1 1/4" tubes from the 1" tubes.
I chose to spend my money on an AMERICAN made product even though it cost more. This is a very well made product.
The upper hose is a Gates 20875.
The lower hose is a Gates 20558. I added a spring to the inside of the hose to keep it from collapseing.

When I first built the car, I had a factory 22" 3 core radiator in the car. It did not seem to cool like it should, so I ordered a "26 inch aluminum two 1" tube cross flow" from Summit and installed it.
What I did not realize at the time, the core size was no larger than the factory 22" radiator.
I have now compared the coolant capacity of these two radiators as well as my new replacement radiator.
I capped the lower hose nipple on the radiators and measured and added water until it just ran out of the top hose nipple.
The factory 22" 3 core radiator held right at 5 quarts of water.
The "26 inch aluminum two 1" tube cross flow" held 3 quarts of water.
The new Wizard Cooling 26" two row 1 1/4" tube radiator holds right at 6 quarts of water. Double what I have been trying to cool the engine with.
The new Wizard Cooling radiator also has 70 sq. in. more surface area then the other radiators.

To install the new 26" radiator, the stock core support has to be cut and widened.
Here is the before photo with the lower portion of the core support removed.(more on that later)

After cutting and widening the core support, I welded 1/8" X 1 1/2" steel to the engine side of the core support to reinforce the mounting points.

I then cut an slotted the top of the core support at the top of these reinforcements so that the flange of the new radiator sets on the front side of the core support.
The aluminum mounting flange of the new radiator is right at 1/8" thick and the core support is right at 1/16" thick.
By mounting the radiator this way you gain right at 5/16" addition fan clearance.

Since I was relocating the new radiator, I decided to lower it so that the bottom of the top tank now sets at the same level as the inside lip of the upper core support.
This will expose ALL of the core to air flow.
This is the reason that I had removed the lower core support in the previous photo.

Due to the fact that I lowered the lower core support, the latch support had to be lengthened.
I cut two spare parts at the large hole and welded them to the correct length.
I also lowered the latch to below the surface of the top of the latch support.
This was done so that I could make a block off plate between the top of the grill and upper core support, again to force ALL air flow thru the core.

The addition of this block off plate forced the redesign and relocation of the hood release to the lower portion of the center latch support.

 

["Dart67"]

Chapter 5 - Fan Shroud

I am using a factory seven blade 18" fan and a Jaguar fan clutch.

The Fan Clutch is a Hayden - Heavy Duty Thermal Fan Cluthc Part# 2675 from O'reilly's.

To help this combination cool better, I decided to make my own shroud.
After researching, I found this how to and followed it.
FanShroud.html has moved
Here are a few photos of the process.

 

["Dart67"]

Chapter 6 - Air Dam
My buddy Shawn gave me the idea for this part of the project.
I have added an air dam below the front bumper, again to direct as much air flow as possible thru the radiator.
This is an air dam from a 1983 Dodge Dakota.

It is mounted to the front bumper brackets with four 1/4" x 1" bolts and 1/4" fender washers.
The air dam is drilled at each of the four bumper bracket locations.

It has to be heated with a hot air gun to form it in place.
Then heat is applied to each end and bent about 90* and trimmed to finish it off.

A side benefit of the air dam is that it has an extension flap on the bottom that extends back to and the width of the lower core support to seal that area.

At this time the car has not been driven due to front suspension work in progress, so I do not know if all my work has helped improve the cooling or not.

Once I get back from the Indy Swap and my trip to Illinois, I will finish the suspension work and take the car for a drive and report back.

Herb

 

[2darts]

Subscribed, Nice detailed pics. Like the shroud idea, Nice work Herb!

 

[Johnny Dart]

Nice fab work,that car should run cool now.
Another thing to look into,is antifreeze to water ratio. Instead of the 50/50 ratio
recommended.Water is better at cooling,so I like to run a 70/30 or 80/20 water/coolant ratio,along with some anti corrosive Water Wetter. This one change alone dropped the temp of my hot running 360 by close to 10degs. Maybe not recommended for the freezing winter months(no worries here in SoCal) but works well when the temps warm up.

 

[pauly v.100]

Very nice work, i especially like the air dam and the thru bulkhead heater hose ideas. thinking of doing this to my remote trans cooler lines.

 

["Dart67"]

2darts,

Thank you for the kind comments.

Johnny Dart,

I run almost pure water here in West Central Arkansas and drain the cooling system for what winter we usually have.

pauly v.100,

I have my trans cooler mounted in in the left front wheel well in front of the tire.
It is a Large Dereale with its own cooling fan and temp switch. I am using AN-6 braided lines and have the lines ran from the trans to the cooler thru the center of the frame rail to hide and protect them.

Herb
I will go out to the shop later and try to get a couple of photos for you.

 

["Dart67"]

Here is a photo of how I have my trans cooler located and mounted.

Herb

 

[74DartSwinger360]

Wow Herb that looks great and should help with coolin problems.
SUBSCRIBED!

 

[BillGrissom]

That is some amazing re-engineering and fab work. The "heater hoses thru frame rail" setup should earn brownie points at a mod. car show, not that I would do it my car and risk rusting out the frame rails.

The aluminum radiator and shroud should be a great improvement. I got a new Be-Cool one on ebay for $80, but ended up putting on my Newport because it would have required cutting off the frame rail lips on the Dart to gain another 1" width, but would probably fit the wider 66+ A bodies.

I have heard the "water moves too fast thru radiator" theory before. It doesn't match anything I learned in engineering and 35 yrs design experience. Indeed, my M.S. theory was experiments in liquid heat transfer. Could be right for some esoteric reason, but more likely another example of how mysterious thermodynamics is to the un-schooled.

 

[GGs66GT]

Check out http://www.evanscooling.com for waterless coolant. It costs more but you will never have to replace it and it won't boil.

 

[KitCarlson]

Nice job on your cooling work.

Since it sounds like you have EFI, and the exhaust is hot. The thought came to me that the ignition timing may be too retarded in places. Retarded timing can easily overheat engine, exhaust, and significantly reduce power and economy.

 

["Dart67"]

Kitcarlson,

The timing is Ok, at one time I did have a problem with it being retarded to far, but that has long since bee corrected.

I think and hope most of my cooling issues are/were due to too small of a radiator and incorrect pulley sizes.
Time will tell.

Herb

 

[Dorian]

That is some amazing re-engineering and fab work. The "heater hoses thru frame rail" setup should earn brownie points at a mod. car show, not that I would do it my car and risk rusting out the frame rails.

The aluminum radiator and shroud should be a great improvement. I got a new Be-Cool one on ebay for $80, but ended up putting on my Newport because it would have required cutting off the frame rail lips on the Dart to gain another 1" width, but would probably fit the wider 66+ A bodies.

I have heard the "water moves too fast thru radiator" theory before. It doesn't match anything I learned in engineering and 35 yrs design experience. Indeed, my M.S. theory was experiments in liquid heat transfer. Could be right for some esoteric reason, but more likely another example of how mysterious thermodynamics is to the un-schooled.

This " theory" is actually fact due to the whole premise of airflow cooling the hot water in the radiator. Same idea as a/c ( hot travels to cold). If the hot water moves too fast thru the rad it does not have enough time in the cooler airflow to transfer.

 

[duster2]

Wow , great work Dart67 , you have got some really inovative ideas ....

Frank

 

[Tony Fields]

Hi Herb

Just read the whole thread after talking to you today at Indy.

You're doing some good stuff there. I really like the shroud.

See you Saturday

Tony

 

[plum crazy dart]

Might have to try that shroud idea my self, yours looks amazing!

 

[Oldmanmopar]

I had to put a restrictor in the thermostat housing to slow the water down. 1" hole. Just a thought. Steve

 

[Oldmanmopar]

I too like the shroud fab work. That is really nice. Steve

 

[inkjunkie]

This " theory" is actually fact due to the whole premise of airflow cooling the hot water in the radiator. Same idea as a/c ( hot travels to cold). If the hot water moves too fast thru the rad it does not have enough time in the cooler airflow to transfer.

Nice work.....and thanks for the detailed write up. Years ago I had a Ranger that I swapped a 302 into it. When I first built it I just used what ever pulleys were laying around.....and it ran hot as hell. I found a matching set at a friends wrecking yard and it solved the problem.
Again, thanks for the great write up....

 

[blue missile]

Great job, Im a front spoiler man as well.
Andrew

 

[cudavert]

I'm totally impressed!.....especially the fabbed up shroud, lowered core support and lengthened latch support! I'm a big fan of oil coolers too......have you considered running one? I had to use one on an A-100 pickup I had with a built 340 in it. When I'd see traffic coming to a standstill on the freeway (from a 70 MPH cruise) it just gave me chills! So I installed an oil cooler and that dropped the coolant temp by about 25~30 degrees in those situations.