Thread: ZZ 502 Running Hot?, then stalls - help!

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Hi All,
Just got a 1940 ford w/zz502 crate motor, single 4 barrel holley, phoenix automatic, walker zac-497 cobra z-series radiator with a "cooling components" shroud fan putting out 2700 cfm. I've had it to 50/60 mph on local roads and the temp continues to rise to over 200. I'm told that the zz502 should run at about 200' and after reading some that seems to be right. The car was built over the past 5 years and had 78 miles on it when I got it,, so it's new but never really driven. I just put in a 160' thermostat after talking to walker radiator (replacing the 180 that came with the car). Here's the symptoms:
1- starts great and idles at about 850-900 rpm.
2- after driving for approx 3-5 min the temp starts to rise and will hold for a short time at 195
3- as soon as it reaches 200 or more the motor runs rough and will stall.

It's not been on the freeway yet because of the cooling problem so I don't know how it will behave at freeway speeds but (in the short time I've owned it I've never seen the temp go down after it heats up). The "Cooling components" guy said to idle it and see what happens,, did that and the same thing happened after approx 20 min at idle but this time I was in the driveway and when it stalled I could swear I heard the gass boiling in the carb. The carb has no spacer intsalled which makes me think I have a gass boiling problem and not a cooling problem. Both walker & cooling components say their products are sufficient enough to keep the motor cool. Also the bottom radiator hose does NOT have a spring in it and the cc guy said the water pump could be crushing the hose causing water flow problems and that hose should be replaced (which does make sense to me). He also said it could be the altinator not putting out enough amps to run the fan properly,, (the car has a russ francis wiring system).

I'm happy to give you guys more info if you want,, just let me know.
Thanks for your help,
Jack

May have the wrong water pump. Serpentine systems and V-belt pumps rotate in opposite directions.

The motor is probably vapor locking. Gas boiling. Under hood temps to high. Crappy gas. Does it have a electric fuel pump? Removeable hood sides. Insulate the fuel lines. Move them away from the exhaust. Make heat sheilds. Ceramic coated headers. Header wrap. Spacer under the carb. Just how hot is the motor getting? Does the shroud have baffels that open at speed to let the air thru the radiator? What temp does the fan come on?

as fitzwilly said, the water pump rotation is suspect. I would assemble the following information:
1. What is the water pump direction (was it intended for a belt system or a serpentine system?)
2. What direction is it turning now?
3. What kind of fan shroud seal do you have? Is there gaps between the shroud and the radiator? Does the shroud cover the entire radiator? Is the fan on the back side of the radiator?
4. Have the pulley ratios been changed?
5. Put a piece of paper in front of the radiator with the engine idling. Does the paper suck to the radiator or blow off? (this tells you if the fan is turning the correct direction)
6. Have you changed the thermostat? Is it oriented correctly? Have you tried it without a thermostat?
7. Did you observe the lower radiator hose when the engine is getting hot? Did the hose collapse?

mike in tucson

Which intake manifold is on the engine?
Did you install it or did it come installed?
Suspicious symptoms of an intake getting over heated.

2700 cfm air flow isn't enough---you need the tauris or lincoln Mk8 fan ( 4500/5000)

This car probably has underdrive pulleys on it also ---there are some street rod drive kits that overdrive the accessories

Your 502 uses the same surp setup as my 572 and requires a short nose reverse rotation pump. As you have described the symptoms, things are fine until the thermostat opens at 190 then quickly go to H**L in a handbasket. Your problem sounds like you have the incorrect rotation pump.

There are insulator spacers that you can buy commercially. There are even thick insulating gaskets. I have used these in the past, but wasn't particularly enamored with the results. I like to make my own from solid wood. Here's how....

First, go online and order longer carburetor studs and two new carb gaskets...
www.summitracing.com
2- MRG55C Holley carb base gasket
http://www.summitracing.com/parts/MRG-55C/
1- AED-6125 long stud kit
http://www.summitracing.com/parts/AED-6125/

Go by any of the cabinet shops I have linked for you and pick up a nice, solid piece of hardwood (not particle board) about an inch thick or maybe a little less and large enough to make a carb spacer from.
http://www.google.com/#hl=en&source=...be5f418103de0b

If you have a drill press at home, you can make the spacer yourself. If not, ask the cabinet shop how much they would charge to hole-saw the throttle bore holes and drill the stud holes for you. Once the holes are sawed/drilled, trim the piece to size and install. It works better if you can leave it an inch or so wider and longer than the carb base. You can coat it inside and out with polyurethane varnish, but unless you have some on hand or know someone that has some, it's pretty expensive to buy just for this project. There's a possibility that some of the boat shops would coat it for you when they are doing another polyurethane varnish job. I've made and run these wood spacers before without coating them, but don't have any long-term results to report.

Oh, and by the way, when this thing is in place, it becomes quite the "show and tell" piece.

CAUTION....Resist the urge to make an open spacer unless the intake manifold is open also. If it's a dual-plane design, than make your spacer a 4-hole design. Bolting an open spacer onto a dual-plane manifold will make a single plane manifold out of it and you will not be happy with the reduced low-rpm performance.

OP--1 post back in Feb and hasn't been back!!!

Originally Posted by jerry clayton

OP--1 post back in Feb and hasn't been back!!!

Yeah, I figure these guys post on several different forums, then run with the first answer they get that sounds reasonable. I thought I would go ahead and answer, just for the benefit of others reading this thread. Thanks Jerry.