My 86 F250 4x4 with 4brrl carb was recently rebuilt (460v8). Runs smooth but still a bit touchy when this Nevada heat hits about 120 deg. I have to punch the accelerator to free up the floats. Before the rebuild they totally stuck! Anyone know of a way to avoid this in the desert heat?

Also, I have the large core radiator but when stopped in traffic the temp (aux gauge)rises to 205 and will drop down when moving. And I hold my speed down on the highway to maintain good temp generally running 190 at about 60-65mph unless climbing a hill. Should I change out the thermostat to a lower temp or should I add an electric fan to the radiator to increase cooling? The radiator has already been flushed.

Fuel. High prices really hurt here. I run 91 octane for optimum performance as I have had problems in the past with fouling and rough engine if I use anything lower. Anyone else have similar problem with the old carb 460's?

Thanks for your input.

 

205 is not that hot a 195 stat opens when engine temp hits 195 it does not limit heat to 195 remember you have a pressurized cooling system and anti-freeze anti boil in you radiator for every pound of pressure in your radiator the boiling point of coolant raises 2 degrees if you have a 14 pound system pure water would boil at 240 degrees with the anti-freeze its probably up aruond 260 is your carb the holley 4160? if so lower your float level a touch the fouling and miss are caused by a rich mixture

 

Electric fan will help with the temp rise when stopped but wont matter much when moving. I am going to do this for mine as getting stuck in traffic on the 405 and having to turn the air off due to climbing engine temps is no fun.

Unfortunately for us, the 295/298 flex fan is the only one desiggned for our trucks and it costs about $300. I have read where people have rigged up fans from cars in junk yards but not sure if they have to deal with teh same amount of heat we do. ( I am in the middle of the Mojave Desert here and the truck sees 100 plus every day of summer sometimes going up to 115.)

I am going to play it safe and get the expensive fan but that is just me. I t may be worth pursuing a regular 16 inch fan from some other vehicle and see if it works. The expensive fan is actually dual 13" if I recall correctly and has fancy hinged vent doors to let in extra air when moving but then shut to force air to be drawn by the 2 fans when stopped.

Good Luck,

Lee

 

Most likely a Motorcraft (Holley) 4180C Carburetor. Fuel level should be just at bottom of inspection port (screw plug on side of float chambers). Have you replaced the thermostatic fan clutch? If it is bad it won't pull enough air through the radiator (either fails to switch speeds or slips). If you replace it, be sure to get the heavy duty unit. Also, consider using a 180 deg. F. thermostat in the engine. A four row radiator (Super Cool Option) rather than the standard three row might be a good choice, too (my '83 has it, yours may have an aluminum radiator). Also, search this forum for "Hot Fuel Return" to see my posts concerning an internal carburetor leak and rich under high vacuum.

 

Some very good thoughts/ideas regarding fuel and radiator. Thanks for the input. That fan at 300$ is a bit high. That will take a bit of waiting. Fan clutch appears to be operational but need to look at closer to confirm. And another project passed on to me is to install a tranny cooler. Lot's of good things.....may need second job to accomplish!

 

If the fan clutch slips you will not get max air through the rad.
One way of easily finding out if it locks when hot is to CAREFULLY try to stop it when engine is hot and idling.
Using a heavy duty thick hide mitt such as a welder's mitt will make it possible.
NOTE that it can be dangerous reaching in to put drag on the fan. It is like trying to stop a small desk fan on the back side of the blades. It doesn't hurt. But if you try it on the front side, it will slice your fingers.
Not recommended for everyone.
If the blades slip, you will be able to slow or stop the fan. If you can't, the fan clutch is good.

 

The 460's had a "hot fuel handling" feature from the factory. Does your truck still have this? It consists of an electric fuel pump(s) in the tank(s), a special fitting at the carb, and a return line to the tank. This keeps the fuel circulating all the time, instead of it sitting in the lines and getting hot, causing vapor lock.

 

Laughingman,
Your 460 should run just fine on 87 octane, mine does. Run a can of Seafoam engine cleaner through it to get rid of carbon buildup. Set base timing (at idle with vacuum advance line disconnected and plugged) to original specification specified on underhood placard. Make sure your catalytic converter (if so equipped) is not partially stopped up (exhaust restrictions can cause overheating problems as well as poor performance).

 

One thing that people often do not think about when stuck in traffic. Bump the transmission into neutral, and take the vehicle out of the "load" situation. Not only are you wasting fuel with it in drive with your foot on the brake pedal, you're also forcing the engine run hotter. Idle speed is higher in neutral, which will give you a few more rpm's on that fan, and reduce the work load of the engine.

Interestingly enough, while I live in a much cooler climate over-all, many of my summer days are in the 105-115 degree F bracket. I've never seen my mechanical guage go over 190 degrees.

 

I got a cheap solution for a mega tranny cooler. Does your truck have A/C? If it doesn't work, you can use the A/C condenser in front of your radiator as a cooler. I just removed the hoses, put some 3/8 elbow fuel fittings on the ends of the condenser, and spliced into the tranny cooler lines. I did it to my truck(85 F-250 460/C6)and it's working great. If you don't have A/C, I am sure you can get the part from a salvage yard real cheap, and it should bolt right in.

 

Sorry. Have not been here for a short while. Appreciate the responses to carb/fuel/radiator question.
Stopping fan while running.....well, knowing my luck lately I'll probably skip this for now! LOL. I probably could try 87 Octane again as I've not tried it since rebuilding the carb. I'll partially fill one of the tanks and try it again. Regarding "HOT FUEL" option.............it doesn't appear I have this. I'll have to relook at it to be sure. I have found that by turning the ignition key forward w/o starting and after buckling up etc. I will go ahead and start engine. I find it cranks right over where it takes a bit longer to start when I don't.

Oh! The other night at storage I had to run the truck so I could have lighting in my storage while we unloaded a moving truck. Although only about 85 deg's the temp on truck was running about 190 idling and slowly rising. Out of curiosity I opened the hood and the temp went down to 180 and held until we finished. Gee....I'll just take the hood off! LOL

Anyway, over the past year the engine was rebuilt, tranny replaced, carb rebuilt, ignition module replaced(keep an extra one always!) and the wife is insisting I sell it off. So let's see...........wife.........or truck?..........tuff one! LOL.

Thanks again. Ron

 

Thanks Sycostang67........That sounds like a good idea. I do have A/C and do not use it as I get no cool air anyway. I will look at this option. Great idea.
Ron

 

As plowpusher said, 205 is not really hot. Lots of vehicles run even hotter by design. My truck has no fan shroud but it never overheats, but in the past I have solved the hot idle by adding a good fan shroud.

 

Your temperature is fine, by design ALL motors run better and last longer when operating in the higher temperatures (say 190-210), so your good there, as my flareside consistently runs in the 200-210 range wether its -35 degrees or 120 degrees.