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Cooling problems with 502 Supercharged motor

10K views 24 replies 11 participants last post by  racecar100 
#1 ·
I bought a 37 Ford Manotti bodied car. It is beautiful. But I seem to have cooling problems.

The coolant has been changed and it takes about 2 gallons, does that seem enough?

The radiator is narrow and tall with an electric fan between the motor and the radiator. The fan is on all the time.

The coolant is all new and fresh.

I just bought a 180 degree as well as a 195 degree thermostat to put in if the existing one is bad. I thought I would pull it out and put it in some boiling water with one of the new ones and see if it comes open at the same point and as wide.

I had it on the road the other day doing a test drive because I want to take it on the Hot Rod Power Tour, but the temp shot up on the gage when we were going down the freeway when it was at 195 degrees to about 210 when we got off the freeway. We were running 50mph off the freeway and slowed down to 30mph when we went past Norwalk Dragway, turned around and came back.

The temps when I got back on the freeway never really came back down to the 195, hovering between 205 and 210.

If it isn't the thermostat, anyone else got an idea? Seems to me that with the 502 and an 871 Littlefield Supercharger with two Demon carbs on top that it probably puts out some horsepower, even though the compression ratio is not so high as to require hi octane fuel. I can get away with 92 octane no problem.

Other thoughts or comments? Is the 2 gallons of fluid really enough for a 502? :confused: If it isn't anyone got a way short of a new radiator to get addiotnal cooling capacity into the motor?

I will post a photo of the car later tonight....
 
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#3 ·
Sounds like you have air trapped in the block. Did you drill a hole in the thermostat flange? This will help allow trapped air out. Also, parking with the front of the car elevated while filling the radiator can help. I don't know big blocks, but 2 gallons doesn't sound like you have it filled.
 
#4 ·
You would have to drain the block to get all the coolant out, draining the radiator only gets out about 1/2-2/3 of the capacity. Without calibrating your temp gauge and checking your thermostat for opening temp its hard to say if you really have a problem or not.

I would start with a thermostat change after testing the new one, running a 180 F one will give you some overhead for hot conditions or driving in traffic.

I will say 210F is not excessive, most newer cars run in that zone when its hot outside. Hitting 240F or higher would be overheating and dangerous to your motor, hitting 260 would be a reason to shut it off for safety. Remember just because the thermostat says 195 on it does not mean the engine will never get hotter than that, it just means that is the full open temp.

Since the car is new to you you will have to get used to the way it operates, changing the coolant for a mixture thats proper for your environmental conditions is important as well as using DI or distilled water for mixing with the glycol. 50/50 mix is ideal for most areas unless you get -40C in your area. Some people swear by using water wetter in the coolant but I have only used it for plain water in a race car where glycol is prohibited, I can't really recommend using it with glycol since it already contains water wetting agents.

I would take a wait and see attitude to your engines operating coolant temperature, holding 210F in traffic or just coming off the highway with a supercharger is not unusual and quite normal. An engine driven 7 blade flex fan designed for air conditioned vehicles is far superior to any electric fan on the market and will cool better on the highway.

Drive it for awhile and see how it goes.
 
#5 · (Edited)
If a system won't cool back down at highway speeds, it is one of only two things. Airflow is either restricted into or out of the radiator core, or the radiator isn't large enough for the system to have enough heat transfer capacity.

First, airflow into the radiator. Is there an AC condenser in front of it? This will degrade the airflow into the radiator.
Is the area in front of the radiator sealed with metal panels, rubber strips, weatherstrip, plastic etc so that none of the air can go around the radiator?
How well is the engine compartment ventilated? Can the hot air get out?
Something that may help is to fabricate an air dam/spoiler from rubber or sheet metal right below the radiator support like many new cars have, this creates a low pressure zone and keeps air traveling under the car from pressurizing the engine compartment and holding the hot air in.

If none of this helps, you can almost bet that the radiator just isn't big enough, a common problem even with smaller engines when they are in a narrow-nosed street rod. Hard to get enough radiator into such a small space.

EDIT: I agree with what Chuck says entirely about the temps and the mechanical fan.
 
#6 ·
ericnova72 said:
If a system won't cool back down at highway speeds, it is one of only two things. Airflow is either restricted into or out of the radiator core, or the radiator isn't large enough for the system to have enough heat transfer capacity.
I'm not entirely sure I agree with that.
Incorrect ignition timing can cause a heat issue at highway speeds. water flow can cause heat issues also. A siamese block engine (I'm assuming it's siamese) with forced induction would be a heat producing worry already. To be honest, I would check the tune FIRST, find out if you are running overdriven, what the timing is set at (initial and total) and make sure it is running as best as possible FIRST, before trying the cooling system itself...
 
#7 ·
Crazy Mopar Guy said:
I'm not entirely sure I agree with that.
Incorrect ignition timing can cause a heat issue at highway speeds. water flow can cause heat issues also. A siamese block engine (I'm assuming it's siamese) with forced induction would be a heat producing worry already. To be honest, I would check the tune FIRST, find out if you are running overdriven, what the timing is set at (initial and total) and make sure it is running as best as possible FIRST, before trying the cooling system itself...
Mopar Guy, good point. I was basing my response off the fact that the OP asking mostly about the cooling system.

To me, the siamese block is a non-issue, it is mostly myth that they run hotter. Otherwise, none of the aftermarket blocks would be this way, and they are. If the cooling system is big enough siamese is never a problem. As far as the blower causing more heat... not at cruise speeds, it's just along for the ride. This assumes the carbs are set correctly, they can add to a heat problem if incorrectly calibrated.

HP is heat, if your not making power, your not making heat, and it only takes 60 hp or less to keep a vehicle rolling at highway speeds

Ignition timing can definately be a problem, blower engines don't like to be even slightly retarded from optimum setting.

I doubt the 8-71 is overdriven if he can run it on 92.
 
#8 ·
ericnova72 said:
Mopar Guy, good point. I was basing my response off the fact that the OP asking mostly about the cooling system.

To me, the siamese block is a non-issue, it is mostly myth that they run hotter. Otherwise, none of the aftermarket blocks would be this way, and they are. If the cooling system is big enough siamese is never a problem. As far as the blower causing more heat... not at cruise speeds, it's just along for the ride. This assumes the carbs are set correctly, they can add to a heat problem if incorrectly calibrated.

HP is heat, if your not making power, your not making heat, and it only takes 60 hp or less to keep a vehicle rolling at highway speeds

Ignition timing can definately be a problem, blower engines don't like to be even slightly retarded from optimum setting.

I doubt the 8-71 is overdriven if he can run it on 92.
I've seen headers glow red from incorrect timing, it wasn't at peak HP levels.
I've seen engines stripped that were detonating like crazy where the owner had no idea the engine was detonating... "I didn't hear knocking/pinging"...
;)

I would check the basic tune and the boost level first, then check the actual cooling system. It surely won't HURT matters, even if it's in good tune.
I eliminate the influencing factors first, then address the problem, but that's my line of thinking, obviously not everyone will agree...
 
#9 ·
Here is the car.....the front has a grill that is wide open...



The 502 with supercharger is shoe horned in there......




The electric fan is up tight against the radiator. There really isnt any room between the front of the motor and the radiator, just enough room for the electric fan.

When you say to drill a hole in the thermostat, does anyone have a photo of what you are talking about? Sorry, never heard of that.....
 
#10 · (Edited)
An 1/8" hole is drilled near the edge of the thermostat plate so air is purged from the engine side. Many thermostats have this feature already from the manufacturer, you may have seen one...there is a small brass pin peened in the hole that is loose and can float. Some mfg's call them a jiggle valve.

Here is an example of a drilled thermostat.



Here is one with a jiggle valve.



Beautiful car BTW. ;)
 
#11 · (Edited)
Beautiful car, outstanding looking, but a small cramped engine compartment, and what appears to be a pretty small space for the radiator. No room for airflow around the engine. I think your gonna have your hands full maximizing every inch of the cooling puzzle to keep it cool enough for highway speeds. Good Luck ;)

IMO, airflow OUT of the engine compartment is going to be your biggest problem.
 
#14 ·
Crazy Mopar Guy said:
Yup, nice car, I love the hood too!
:thumbup:

Is the temperature issue your ONLY issue that you have as far as drivability goes?
the only issue so far.....had a brake issue, seems that someone before had tried to take a wire brush and got metal pieces in to the brakes....new brake job and a good bleeding solved that problem.

Would tend to be a handful when getting on the gas, but after looking at the underneath that panhard bar (not sure that was correct terminology) did not have the back end centered. It is now centered and seems to be a bit easier to goose.

The whole car is a work of art. Everything and I mean everything was put together with an eye to detail. The bottom of the car is equally as nice as the top of the car.

I am planning on putting the car in my trailer and taking it out to Hot Rod Power Tour in a few weeks. Worse come to worse, it will ride in the trailer more than I might like, but it is a real bad ride. It gets peoples attention as it drives down the road between the rumble of the big block and the roar fo the super charger, it is a bit wild.

I have driven the car a few times before this and the temp never went above 195 and that trip was much further than this one. No problems with it over heating more than the 195. I am hoping it is just the thermostat.

Car has Ford 9" w/4.11 gears, 4 link set up. MT 18" wide tires on the rear. 8 point roll bar, trunk and interior finished in leather. Built in dash DVD player.
 
#16 ·
ericnova72 said:
Beautiful car, outstanding looking, but a small cramped engine compartment, and what appears to be a pretty small space for the radiator. No room for airflow around the engine. I think your gonna have your hands full maximizing every inch of the cooling puzzle to keep it cool enough for highway speeds. Good Luck ;)

IMO, airflow OUT of the engine compartment is going to be your biggest problem.
maybe that is an issue too. I loked at the engine compartment and it is tight with not a lot of ways for air to flow out. I might have to make up some new side panels with louvers and see how it works...if it was to solve the problem, I will have to figure out how to get it painted to match.....
 
#17 ·
firstgear said:
Would tend to be a handful when getting on the gas, but after looking at the underneath that panhard bar (not sure that was correct terminology) did not have the back end centered. It is now centered and seems to be a bit easier to goose.
A panhard rod for a locating device on a short rear end will pull the diff side to side more through the suspension travel. The longer the panhard length the better...

195 isn't really very hot, 210 is livable also... if you want to try airflow can you just remove the hood side panels and drive the same route, see if it makes any difference in temps?
 
#18 ·
I work for a cooling company. We had a guy with a similiar motor in his car. The blown cars make much more internal heat than a carbureated one. After beating our heads against the wall for weeks, I finally told the guy to make sure the carbs were set up for the blower. He assured me they were, but with some doubt he took the car to a chassis dyno. Well, at speed they found the carbs were leaning out , making the motor run hotter. They fattened up the jetting and he has a hard time making heat now. Also, I want to tell you that 200-210 IS NOT HOT!!!. Most hi-po motors need to run arond that temp to achieve efficient burn in the cylinders..........240-250, that's hot.
 
#19 ·
Crazy Mopar Guy said:
195 isn't really very hot, 210 is livable also... if you want to try airflow can you just remove the hood side panels and drive the same route, see if it makes any difference in temps?
good suggestion....I will keep that in the back of my mind in case I really run into problems on the HRPT. We will be at the first 3 stops, debating right now on going up to Detroit area or not.....but the first three stops are near enough to my kids for us to get a cheap place to stay overnight.
 
#20 ·
sunsetdart said:
I work for a cooling company. We had a guy with a similiar motor in his car. The blown cars make much more internal heat than a carbureated one. After beating our heads against the wall for weeks, I finally told the guy to make sure the carbs were set up for the blower. He assured me they were, but with some doubt he took the car to a chassis dyno. Well, at speed they found the carbs were leaning out , making the motor run hotter. They fattened up the jetting and he has a hard time making heat now. Also, I want to tell you that 200-210 IS NOT HOT!!!. Most hi-po motors need to run arond that temp to achieve efficient burn in the cylinders..........240-250, that's hot.
hmmm, chassis dyno might be an answer as well. There is one near me and I had the guy fuss with my '60 EFI Corvette and he did a nice job. This might be the ticket as well.

I have driven the car before to where I work, about 35 miles one way and did not have a problem with the temps spiking to 210, they pretty much stayed at 195. I am going to take a run at the thermostat first. I bought a 195 and 180 from Summit.
 
#21 ·
Timing and coolant

1) check timing. Blower motors usually have low CR and need lots of timing to run cool. On my SBC, 671 at 1:1, CR 8.5, I run 30 initial plus 20 centrifugal.

2) Coolant: antifreeze is not a good coolant; use only enough for your climate. I live in TX and use no antifreeze, just distilled water and Red Line Water Wetter.

3) As long as the motor doesn't boilover (boiling water and steam from the overflow and the temp soaring), don't worry. My car runs 230 in the summer with no problems. I run a 7# cap in winter and switch to a 16# cap in the summer. Higher pressure gives more margin before boilover.

4) The carbs should be boost-referenced to avoid leaning at high load. Some folks just run them rich to avoid the problem, but that leads to fouled plugs and poor mileage.
 
#22 ·
That thing is nice!!

I agree with the others. I was initially thinking head gasket prob between Mark IV & Gen V blocks, but it would be in the 240*+ range.

Is there a underbody pan?

Just remember, the radiator needs plenty of air, but the engine compartment also need an bigger exit area so all that heated air can get out.
 
#24 ·
Tweakman said:
1) check timing. Blower motors usually have low CR and need lots of timing to run cool. On my SBC, 671 at 1:1, CR 8.5, I run 30 initial plus 20 centrifugal.

2) Coolant: antifreeze is not a good coolant; use only enough for your climate. I live in TX and use no antifreeze, just distilled water and Red Line Water Wetter.

3) As long as the motor doesn't boilover (boiling water and steam from the overflow and the temp soaring), don't worry. My car runs 230 in the summer with no problems. I run a 7# cap in winter and switch to a 16# cap in the summer. Higher pressure gives more margin before boilover.

4) The carbs should be boost-referenced to avoid leaning at high load. Some folks just run them rich to avoid the problem, but that leads to fouled plugs and poor mileage.
I live in northernOhio, so we need to protect for -20 dead winterworse case.

I wasnt hard on the motor, just crusing down the freeway at say 55-60, about 2800 or so RPM. It is a scarey thing when you get on it hard, things happen real quick and the car can get away form you if you are not careful. So my spirited run ups are with caution these days.....I would imagine as I get used to it then there will be enough predictability and more spirited driving.
 
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