Small block mopar overheating

I've searched and educated myself a bit but I want to hear what you guys suggest.

My 1950 dodge has a 360 chrysler motor, 1966 v8 mustang radiator with a 13 pound cap, a 195* thermostat, and a 10 inch flex fan with no shroud. Also, I'm running a mechanical advance distributor out of a 1979 Chrysler Cordoba(what the 360 came out of)

When driving on the highway it never goes above 195*. But today I made my first voyage through town in 80 degree temps outside. The temp gauge quickly went up to about 235* in the stop and go traffic and puked everywhere when I got home.

Should I mess with putting a higher pressure cap on it?? Should I change the thermostat to a 180* or 160*?? Or should I look into changing my fan and getting a shroud?? My fan has to be that small to clear the lower radiator hose so my only other option is an electric fan.

Thanks for the help.

 

I have had some problems with my 360 in PHX but it was 125 degrees out in stop and go traffic, it could be any way at that temp but I put electric fans on and it helped a little, but a shroud is probabily the problem.

 

Yeah I know that not having a shroud was a no-no, but there really isn't very much room in the engine compartment... I'm thinking a combination of all of these is my problem. I'm also going to check and make sure the fan is turning in the right direction and sucking air in the morning.

 

Definatly put a shroud on it first. It will drastically improve low speed cooling.

 

make sure everything is good, water pump, etc.
and that the heater core if you have one hooked up is not plugged up..

check the small bypass hose from intake to pump mine would weep thru the hose with no visible holes and cause it to overheat changed it and no problem since

 

Water pump is brand new and no heater in the car.

 

That 10 inch fan is not going to cut it hold a piece of paper up to the radiator and see if it is drawing air across the entire radiator. if not try a shroud. My 360 will run all day in any temp and never overheat but it is a 15 inch fan and shroud

 

Pull your thermostat and test it to see if it's opening and closing properly and at the right temperature. I've had several bad ones right out of the box. Fan shroud should be first and foremost, though. What is the condition of the radiator? Did you have it boiled or anything before using it?

 

My fan is 10 inches because any bigger and ill be slicing my lower radiator hose. I cant mount my radiator any lower because of the front crossmember. The mustang radiator is brand new. But the motor has never been rebuilt and the water passages could have crap in them.

 

Do you guys recommend building a shroud or is there someone out there selling universal fit ones??

 

Have you considered the fact that the heat exchanger you're using might be undersized for the application? You have a radiator sized for a 289ci on a 360ci, a 71ci difference. A Dodge Ramcharger with a 360 would have run something like an 18"x26" core size while a '66 Mustang would run approximately 16"x17". That's a good bit of surface area to sacrifice.

 

Im running into that problem myself, I think building one is the only way to go for odd ball applications.
My radiator is to high in comparison to my mechanical fan, the fan sticks a few inches below the radiator. I dont know if thats the same problem you have. my radiator is the stock case and stock upper tank. the core has been updated from the old honeycomb to the newer style. but even with that issue it still runs all right temperatures ( usually not above 210) in PHX during summer as my daily driver. so maybe your passages are plugged up, its one of those things you are gonna have to chip away at. my advice would be start at the cheapest point and work you way up.

 

A non vacuum advance dizzy in the late 70s? That seems bizare, but never messed with late 70s. A part of the "Lean Burn" system, maybe? Not that it nessisarily has anything to do with overheating, but I'd think you'd do better with a vac advance dizzy in it.

 

Yes a vacuum advance dist will let it run cooler in traffic.

 

That's another thing there wasn't any room for. It's a stock application distributor, so I figured it would work. The motor is close to the fire wall to the point that I wasn't able to time it properly with the vacuum can hanging off the side.

 

Don't start throwing $100 solutions at a possible .10 problem.

As previously stated, check the thermostat and fan pull.

Check for flow, it wouldn't be the first time a "new" water pump was no good.

Check for a kinked or collapsed hose. When hot, possibly pulling dissimilar pressures, hoses will do the "golf ball through a garden hose" routine.

 

Yep, ditch that lean burn crap. If the carb is off the same engine, it will need rejetting too. lean burn had the vacuum advance on the computer, not the distributor. You must run the full system, all or nothing, for it to work.

 

It's got an edelbrock manifold and 1405 carb on it. The car already had the lean burn stuff replaced when I got it. It had a vacuum advance distributor on it, but I had an oh shit moment when I was setting up my motor mounts and noticed that the advance can was way too close to the firewall. I went to the auto parts store and told them and was told that there's a mechanical advance distributor for my application. So I gave it a shot, totally unaware of the headaches it would cause.

 

Greetings! One thing not mentioned yet, you need to make sure the inlet and outlet are on opposite ends of the radiator tanks (like upper on driver's side, lower on passenger side of radiator), not the same side (I.E., both on driver's or passenger side). If they are on the same end, the water will "bypass" part of the core. Friend had this problem on his '66 Fairlane, changed to a later radiator, problem fixed.

 

BHF will fix that clearance problem for the vac advance . . .

I think your Fan is way too small, and with no shroud is doing nothing. Logically thinking, at speed it cools okay, so the rad is probably just adequate. Get enough air through it and it will work. It would seem with your clearance issues that an electric fan (such as one off a Ford Taurus) is your only option here.

 

just clock the wires around the cap to get where you need, then use the little room for turning to fine tune the timing where you want it.

 

A teeny radiator would be enough if enough air is forced thru it.

Checking (measuring) the temperature profile across the radiator face when it is overheating will provide some idea if the pump is pumping enough.

Could the distributor be clocked differently to make clearance for a vac advance?

 

Well I fired her up and checked to see if the fan was running the right way and it sucked a piece of paper so tight to the radiator that I had a hard time pulling it off.

I have the vacuum advance distributor that came off the 360, should I swap it out first thing? Because not having any advance at idle makes sense, it would make it run like a pig right?? Rough and rich??

Also, do you guys think I should mess with changing the radiator cap to something like 15psi??

And should I put a lower temp thermostat in??

 

A higher pressure cap won't bring the temp down, it will just let the temp rise higher before it releases and lets the radiator puke.

On your fan, I don't think it is covering enough of the radiator although the radiator may be too small for the Mopar 360, those things usually have hell for big radiators even in the mid size cars.
I've a fan very similar to what you have on that on the 250 in my 48 for very similar reasons and it did the same thing in warm weather. It ran 180/183 or so running down the highway with a 180 Thermostat and then as soon as you hit town and got in traffic the temp shoots up because the fan just won't pull enough air through the radiator and doesn't pull any air though a big portion of it. I don't care for electric fans on older rigs but I think that would most likely be the simple fix for you. I'd go with a fan off a production front wheel drive car rather than an aftermarket fan though. A lot of guys run the Ford Taurus fans with good luck and one off a mid 80's or later Cad Deville might work pretty well as they are fairly thin and pull a hell of a lot of air. The fans on the 88 Deville I had would just about suck a cat through the radiator when they came on.

 

I had the same problem on a '52 Chevy. It ran fine when the freeway was wide open but would get up to 210 in traffic. I switched to a 4 row triple pass radiator but it still ran hot in traffic. I checked the timing and the advance was frozen in full retard, Swap distributors and now she runs at 140, 180 with the A/C on.

 

The higher pressure cap will allow the water to run hotter before boiling than a lower pressure cap. The 195 should be good, but get a shroud in place before putting in a 180, & I wouldn't go any less.

 

late timing will make it idle a bit rough because you will have to open the throttle more to get the speed up - when you have them open just too far you uncover the transfer slots and start pulling more fuel in. It will also make it run hot at idle, which may be a large part of your issue.

I would the put the vac advance distributor back in and get the timing set properly - should be like 8-10 degrees advanced (with the vac advance line off and plugged) to start, about 34-36 total.

 

From experience I can tell you that you radiator is at best marginal as far as size for your application. A larger fan and more importantly a shroud will be a great help in this deal, but you will end up making your own shroud. Drop that thermostat down to 180, too. I had basically the same problem with my Plymouth in the early days when I was running a radiator that would fit within the stock core support. I solved the issue by building a new core support and hanging one of Ron Davis's huge stock car crossflows across the front and machining a Moroso Small block Chevy thermostat filler neck to work on my Edlebrock manifold. With that and a 7 blade Caddy clutch fan and shroud I can idle on any 125 degree day all day with the A/C blowing ice cubes, aluminum heads and all!

For your distributor woes, Mopar performance sells a distributor kit with a properly curved vac advance dist and H.P. control box for lots cheaper than you would think and it makes a big difference in the car's performance. So many of their seventies distributors had a super lazy curve that was intended to enhance emissions control, not performance. Just for grins, set your timing at 18 initial, and shoot for 34-36 total. a vacuum advance correctly hooked into ported vacuum realy shouldn't effect low RPM idle temps. It's deal is to pull a bit more advance at mid range cruising speeds.

 

I had a 1978 360 Magnum with 202 heads, and Crane Cam in my '33 Ply. 727 tranny. with 8" Ford rear & running 411 gears, and i never had any trouble. The difference, i used a Walker Radiator. I found out a long time ago, not to go cheap when it comes to cooling.. You need a three core radiator at the minimal.

If you wish, you can find a original radiator, and take to radiator shop, and have them re-core it. Good Luck. Check with some area radiator shopps and pick their mine !

 

Took a minute to step out and Photograph what I was yammering about. I designed this whole thing as a unit around an easily replaceable and inexpensive high performance radiator that had lots more capacity than I actually needed. Just an idea for ya...