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Cooling the MGA

Moss Motors
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ghnl Avatar
ghnl Silver Member Eric Russell
Mebane, NC, USA   USA
1961 MG MGA "Calvin"
Seeking advice & BTDT's for cooling my MGA. I have a blanking sleeve (no T-stat) and an aluminum radiator - approx same size/capacity as the original MGA radiator. 10 row oil cooler mounted on top of the shelf in front of the radiator. I don't have an oil temp gauge.

When I was running it with the engine driven fan & Moss shroud coolant temps would stay in the 180-185F range. Without the engine fan temps would be in the 200-220F range.

Last year I had a single 10" electric fan (pusher), this year I tried two 9" fans side by side but it still runs >200F without the engine fan (and it was quite cool at VIR last weekend).

Any ideas about keeping my cool and avoiding the HP drag of the engine fan..?. I'm thinking of re-mounting the oil cooler below the shelf to avoid blocking the radiator. What else?



Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

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billjamesSTJames Avatar
billjamesSTJames Bill James
Southport, NC, USA   USA
I assume you have removed every other tooth in the grille. You can added "shark gills" to the inner fender. If you remount the oil cooler (19 row?) under the rad panel with ducting. You can seal the other ducting openings so you force the air through the rad.

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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"

Not allowed per the rules.

Eric, a couple of tips that have worked well for me, give your oil cooler and radiator dedicated separate duct work, a oil cooler sitting in front of your radiator doesn't always work. I don't believe in the blanking sleeve while they do block flow to areas not needed for racing, they still let too much flow happen too quickly. You need slow the flow down, so the water stays in the radiator longer, I do that with limiting washer where the thermostat normally sits, about 5/8" hole, now this has been debated here before, but I never see over 200 degrees on the hottest of days, and I done this now for many years with success as you well one in one of the hottest places to race in the country in the summer. All the work I did to my ducting has paid off well,and even allowed me to run a smaller oil cooler and have lower oil temps that I did with a bigger oil cooler.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 3 time(s). Last edit at 2018-04-16 10:04 AM by Speedracer.


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ghnl Avatar
ghnl Silver Member Eric Russell
Mebane, NC, USA   USA
1961 MG MGA "Calvin"
Yes, I have removed every other slat in the grill and made sure the remaining slats are aligned with the air flow.



Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100


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730MGA John Bries
Denver, CO, USA   USA
Hi Eric,

I had problems with my A's cooling and found the best solution for me was to create a closed system with a air bleed at the highest point. Learned this from a Civic I had years ago. I took a late MGB thermostat housing, the one with the alternator arm and bleed screw on top. Cut off the arm, rotated the housing closer to the original position on the A, then modified the bleed screw to accept an elbow with a hose that runs to a header tank mounted on the heater shelf which uses a pressure cap, maybe 12lbs?

Had to reinstall a 180 thermostat since it runs so cool.

I rarely use the pusher fan even on the hottest days racing at Pueblo in August = upper 90's at altitude!

I've also bent the grill vanes to allow more airflow and the oil cooler is below the rad duct panel. The biggest help was the closed system.

Also need to mention I am running a closed aluminum radiator, no fill or overflow.

Best of luck and have a great season!



Edited 1 time(s). Last edit at 2018-04-16 09:38 AM by 730MGA.

fast-MG.com Avatar
fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
I agree with Hap. Maximize air flow through the grill and duct the air so all goes through the rad.


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kabover John F B
Mukwonago, WI, USA   USA
1969 Lola Race Car "Big Blue"
In reply to # 3717823 by Speedracer
Not allowed per the rules.

Eric, a couple of tips that have worked well for me, give your oil cooler and radiator dedicated separate duct work, a oil cooler sitting in front of your radiator doesn't always work. I don't believe in the blanking sleeve while they do block flow to areas not needed for racing, they still let too much flow happen too quickly. You need slow the flow down, so the water stays in the radiator longer, I do that with limiting washer where the thermostat normally sits, about 5/8" hole, now this has been debated here before, but I never see over 200 degrees on the hottest of days, and I done this now for many years with success as you well one in one of the hottest places to race in the country in the summer. All the work I did to my ducting has paid off well,and even allowed me to run a smaller oil cooler and have lower oil temps that I did with a bigger oil cooler.



Dumb Question???

If you are slowing the water flow down to keep it in the radiator longer, so it has time to cool, are you not also keeping it in the engine longer, to heat the water up more?
Just as you are trying to increase the air flow through the radiator for more/better heat transfer, you should also increase the water flow through the system for better flow. A pressurised system will do a better job of heat transfer that non pressurised as small air bubbles are not created. Your limiting washer is helping to pressurise the block side of the system helping to stop the creation of bubbles. Just my opinion.

john f

Hemidavey Dave Rudziensky
Grosse Isle, MI, USA   USA
Moving my oil cooler below the "shelf" and opening up the front valence to get airflow to it helped a lot. Would blocking off the round air ports in the core support to force the air through the rad core help? Also we have found that a pusher fan can block 15% of the core, the motors can be quite large on some models.

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Blueosprey90 Avatar
Blueosprey90 Jeff Sienkiewicz
New Milford, CT, USA   USA
Eric, I believe Hap's limiting washer is nothing more than a fender washer. I ran whatever he installed in the race motor. My question was always whether the motor ran too cool, as I had a hard time getting to about 160-165.

I should probably go to Home Depot and buy one for your/my new engine. I run the stock radiator, stock fan, oil cooler mounted in front of the radiator and every second slat removed with the Moss Motors radiator shroud.

ghnl Avatar
ghnl Silver Member Eric Russell
Mebane, NC, USA   USA
1961 MG MGA "Calvin"
In reply to # 3717872 by fast-MG.com Maximize air flow through the grill and duct the air so all goes through the rad.

I have the top of the radiator to bonnet space blocked off. The duct where the heater air supply would go is blocked off with a plastic cover from a can of snack peanuts (exact fit!). The carb side has a 4" hose to direct some outside air to the carbs. I have a 13 lb radiator cap - I've pressure tested the cooling system and it holds pressure for a few hours.



Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

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malcox Avatar
malcox Silver Member Malcolm Cox
Napa, CA, USA   USA
Hi Eric
We have alternate vanes removed.
We have a fan, usually switched off during racing.
On hot days >100 deg, using the fan while racing will drop temp by about 10 deg
The blades are about 11" dia (hard to measure) the fan plastic safety grille is cut away.
I think I could still remove some motor support struts if I could be bothered.

We have oil cooler under the radiator. When I installed a new valence, I tried to avoid cutting a hole for oil cooler airflow, didnt work, oil way too hot.
I don't have padding on top of the stock MGA radiator.

The first shot is my installation.
FYI, the second image is some MGAs running in UK
Cheers
Malcolm


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Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
I relocated my radiator more forward than stock on my B, I did this because I wanted to add a puller electric fan, but more so for if I have to spend more time in the paddock getting to the grid, or back to may paddock spot, it give me a ways to keep the temps down. I do not run the fan while on track and you should try your best to get enough air to cool your car while on track without the aid of electric fan. A pusher fan, will block airflow when not being running while on track, if your temps are good that way, then fine, if not, relocating the fan so you can so you can use a puller fan will eliminate this airflow block. Most of my cars never had a fan of any sort, but I now drive my car to the grid, and at some vintage races/venues can put you on quite a journey to get to the grid. I added the aftermarket fan after having to sit way to long on 63 car grid at the Mitty.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
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Rick Starkweather Avatar
Raleigh, NC, USA   USA
Hap:

Why do you think electric water pumps are not allowed? I have not seen anything in the rules on this, but may not be looking in the right place.

Rick

bills Avatar
bills Bill Spohn
W. Vancouver, , BC, Canada   CAN
1 - there is nothing wrong with running 200 F. In fact there is nothing wrong with running even higher as long as the coolant doesn't boil. Assume you have modified the radiator neck to allow the shorter modern pressure cap so you can run a 15 psi cap or whatever to allow a bit of additional margin in needed.

2 - there is a lot to be gained by ensuring good sealing around the radiator. That can include making sure the thick felt strip is still on the bonnet, blocking the heater duct hole so air that would escape that way has to go through the rad, and having the oil cooler under the radiator horizontal pan

3 - electric fans are of use only when you are sitting in pre-grid overheating because they take too long to get you on the track. Once you are moving, they are just in the way and will actually slightly reduce cooling by blocking a bit of the available flow area.

4 - not all organizations will allow this, but here is my engine bay with the radiator moved right up to the bonnet opening and well sealed. It is a double depth core - I used an MGB tank to make the bottom tank the same depth as the top tank on the MGA, with a modern optimal core. If the weather was cool (it happens up here in BC) I sometimes had to put racer's tape over half the radiator to get it up to proper running temp (I run a restrictor rather than a thermostat). The right side opening is there for the carbs, but the right side is blanked off.





Bill Spohn www.rhodo.citymax.com/carstuff.html
Current: 1958 MGA Twincam (race car (170 bhp)),1962 MGA Deluxe Coupe (98 bhp)
1957 Jamaican MGA (200 bhp)1965 1971 Jensen Interceptor (350 bhp)
2009 Pontiac Solstice GXP Coupe (350 bhp)
2007 BMW Z4M coupe (340 bhp)
Recent: 1969 MGC roadster (175 bhp),Jensen CV8 (375 bhp),
1969 Lamborghini Islero S (350 bhp), 1988 Fiero GT turbo (300 bhp)
North Vancouver BC

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