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Circle Track Overheating Issue 351C
#1
Any suggestions will be greatly appreciated!!

I run a 72 Mustang at the local 3/8 pavement circle track.  I cannot keep water in the radiator.  It seems to run cool (around 200 degrees) during the race, but if a caution or red flag comes out and I drop rpms below 2k, it starts flowing out the overflow and building temp.

351 Cleveland, Bypass Block off plate installed, AFCO 80102FN radiator, 6 blade mechanical fan, Good fan shroud, Duct work in front side of radiator to direct air flow. Jegs high flow water pump, slightly smaller crank pulley, no thermostat or restrictor (Although I have tried everything). I’ve tried different caps ranging from 20-35 psi.

I have ran without the nose cone to see if it was blocking air and I had the same issue.  Plenty of air is directed from underneath to the radiator with the duct work.

I have recently ordered AFCO dual electric fans with a shroud made specifically to my radiator but I have not installed it yet.  That will happen this week but I not certain it will fix my problem.  I am mainly doing it for horse power reasons.

Thanks for any help in advance!
Jim


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#2
Who assembled the motor? A member on here had the same issue recently. Turned out one of the head gaskets was installed backwards.

73 Grandé H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

- Jason


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#3
Cool car!

Since your issues manifest when the car isn’t moving my guess is insufficient air flow through the core.

Where is your temp sending unit, and do you see an increase when it starts pushing water out?

-Matt
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#4
jdwest 711,
Are you allowed to use an electric water pump ?
I would suspect that your water pump speed may be a tad low at lower rpm's and with your gearing not enough air flow, perhaps a Pantera aftermarket water pump pulley ?
Without a thermostat (or thermostat shell) you run the risk of pushing the coolant too fast at race rpm and that does not cool well either.
would be interesting if you could measure water pump speeds at rpm's compared to what stock is and somehow convert that to coolant flow, still pretty sure that you do not have enough air flow at slower track speeds due to gearing.
I would play with pulley sizes until you are compromised at race rpms.
With an electric water pump you could select your water pump speeds regardless of engine rpm.
Boilermaster
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#5
Many race cars don't use the static fan -- they opt for High flow electric - also they don't use water for coolant -- they have the engine set up to run Evans fluid. https://www.evanscoolant.com/products/hi...e-coolant/  - this has a far higher boiling point -- although may need a rad and pump change to do it.

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#6
(06-09-2019, 06:11 PM)73pony Wrote: Who assembled the motor? A member on here had the same issue recently. Turned out one of the head gaskets was installed backwards.

I built the motor, and I am very sure they are on correct.  I was aware of that possible issue when I built it and I have built several Clevelands.
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#7
(06-09-2019, 06:29 PM)mjlan Wrote: Cool car!

Since your issues manifest when the car isn’t moving my guess is insufficient air flow through the core.

Where is your temp sending unit, and do you see an increase when it starts pushing water out?

-Matt

The sending unit is in the water pump right below the capped off heater core hose tube.  Yes, it starts pushing out water and temp starts climbing.  Hopefully my new dual electric fans from AFCO pull more air thru the core.
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#8
(06-09-2019, 06:37 PM)boilermaster Wrote: jdwest 711,
Are you allowed to use an electric water pump ?
I would suspect that your water pump speed may be a tad low at lower rpm's and with your gearing not enough air flow, perhaps a Pantera aftermarket water pump pulley ?
Without a thermostat (or thermostat shell) you run the risk of pushing the coolant too fast at race rpm and that does not cool well either.
would be interesting if you could measure water pump speeds at rpm's compared to what stock is and somehow convert that to coolant flow, still pretty sure that you do not have enough air flow at slower track speeds due to gearing.
I would play with pulley sizes until you are compromised at race rpms.
With an electric water pump you could select your water pump speeds regardless of engine rpm.
Boilermaster

The rule states: Aftermarket rocker arm covers, oil pans, water pumps and pulleys permitted.

So I assume, yes we can run an electric water pump.  I did not know you can select the speed on it.  Thanks for that tip.
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#9
(06-10-2019, 12:20 AM)1sostatic Wrote: Many race cars don't use the static fan -- they opt for High flow electric - also they don't use water for coolant -- they have the engine set up to run Evans fluid. https://www.evanscoolant.com/products/hi...e-coolant/  - this has a far higher boiling point -- although may need a rad and pump change to do it.

Track rules, I have to run water.  Everything else it just as hard to clean up as oil on the pavement track.
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#10
Ok when something like this takes place you do not start throwing parts at it. I would go back to the basics.
First I am the one that bought the car off ebay that had sat in a Sprint car racers garage for 25 years. He claimed that his pit crew built the engine, bored .050", flat top pistons, cam, headers, 2-V heads with a Edelbrock performer and holley. MSD ignition.
When I asked why he did not drive he gave me the story that he had taken the car from California to Reno to his summer home and just never drove it.
When I got the car it sat another two years while I cleaned it up and checked it all out. All I did to the engine was pull the valve covers and everything was new and spotless. I changed the oil and the first time I drove it would almost get hot while going and when you stopped and turned the engine off it would blow the coolant out.
I researched the shape of the Cleveland head gasket and found that the rear bottom corner has a radius on it and the front bottom corner is almost square. I looked with mirror and he had put the R.H. gasket on backwards. They are stamped FRONT. That does not allow the correct flow of water in the head so when you shut it off it boils the water in a hot spot in the head and blows the coolant out.
#1 Verify head gaskets on correct way.
#2 I would put the factory baffle back in the block and get the correct 192 deg. thermostat and install it back like factory. There was nothing wrong with the design of the water flow in the Cleveland.
#3 When I worked in race shop we always put a thermostat in or a know size washer in place of the thermostat. With the dual flow pattern of the Cleveland you need the thermostat. On local tracks my boss knew from trying different hole sizes what to put in a 327 Chevy or a 289 Ford to take away the possibility of the thermostat sticking closed or open. The C engines got 192 deg. thermostat.
If you do not have a restriction for sure the water just gushes through the radiator and does not have time to drop any heat off.
I have also found that the Lucas gas additive drops the engine temp significantly. When I drive the 73 vert with the built engine in 90 deg. + heat I have no over heating issues and have not blown any water out. Catch can always empty and radiator full when I check. I drive in town in stop and go and no issue. I got stuck in traffic on interstate the other day with a crash and was 30 of moving a few feet at a time and no issue. This car is automatic with cooling still in radiator and also AC. I do put out of gear when stopped to prevent the high stall converter from building so much heat.
If you cannot find a thermostat I can get them here for sure.
I believe with you sitting still the water is just gushing through the radiator and without an air flow to take some heat it just keeps building until you boil.
You could get very inventive with say an adjustable restriction in the thermostat housing that you could control the amount of flow. Maybe even with a remote adjustment. Like a gate valve with a cable and nob on the dash that you could open and close.
I would not just go start throwing parts at it. It for sure sounds like a flow issue or head gasket. You can check the gasket without pulling head that is easy with mirror. Just look at a gasket to know what to expect to see.
If you have the tool to check for blown head gasket I would do that to take that question off the table. The blue liquid changes color in the presence of exhaust gas in the radiator.
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When a man is in the woods and talks and no women are there is he still wrong??
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David
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