temp rises on freeway

[68DCharger383]

Guys,

Ive got a got thermostatic fan pulling air through a shrouded stock radiator on what used to be a stock 2b 383 with single exhaust. It is not a daul exhuast 750 pefromer on dual plane edelbrock intake with performer rpm package. If i crusie at 65 which is about 3500rpm with the 3.91 rear, the temp guage will steadily climb to the right nearly touching the 230 mark. Based on the facti can feel air moving at my ankles when standing next to car at idel, im sure its not an airflow issue, besides it is at 65 where the problem occurs. Am i simply under radiated? If so, what can i get the drops in without fabrication and will clear the fan. As it is now. you can barely get the fan belt passed the core and the fan blades. It takes some manuvering for sure. Water pump is stock and flows well, you can see the steady brick flow when looking into the radiator opening.

[wilks3]

I know this is going to sound dumb, but try this. Take the fan off, yes off, of the car. Use shorter bolts to hold the water pump pulley on. Go drive the car down the road. I'll bet with the fan being so close to the radiator that its actually blocking the air from going "through" the radiator.
You are supposed to have at least 1 1/2" between radiator and the fan. Try it, its free.

[wilks3]

Did you change the fan clutch or radiator? The fan blades should be half in and half out of the shroud. Is the radiator plugged up in the bottom coils? Blip the throttle and watch bottom rad hose, is it sucking closed? Anybody else?

[5spdcuda]

The point about the lower radiator hose is well taken. If the spring in the hose is defective the hose could restrict the flow. It is also possible but unlikely to have a head gasket leak into the water jacket and not have any noticable water in the oil. I think the most likely explanation is either a dirty or undersized radiator. If it turns out to be a size problem, then width is more important than depth. If you decide to go with an aluminum radiator, a 26in. two row Afco will cool just about anything. The Afco unit will require you to make brackets, but it's cheaper than most others and very tough as they are used by a lot of dirt track stock car racers. Don't forget to check the thermostat.

[wilks3]

Thermo fan off, runs cooler, now what? Flex fan with the correct spacer to get clearance between rad and fan. Or electric fans. A bigger, wider, radiator will work but you will have to cut the support (22" to 26" wide) out to fit the new rad. The changes you made shouldn't have made car run that much hotter. If you can drive around town and not get hot but out on the road it does, still sounds the air is being blocked somehow. Hope any of this helps.

[volare360]

I had a /6 that would get hot like you have
it was the water pump
wasnt circulating the water fully
It LOOKED fine through the rad and everything
no leaks ect
swaped pumps and fixed the prob
doesnt sound like your issue
but food for though

also
is your fan going the right way
helped a freind with his car,and the electric fan he cobbled in was pushing the air out the rad
at highway speeds it wasnt cooling

again
just a few things I have personally came across
the last one I got right away,when I was looking at it was pushing the hot air at me--stupid chevy guy anyways

[68DCharger383]

Interesting points on the lower hose, which is not collasped. Perhaps i do need a higher volume pump. I am running a stock pump now, but the motor is putting out 100 more horse then it did bone stock. I just assumed the same radiator was used on 440 and therefore should be adequate, but thats why im here. I really do not want to cut brackets and make a mess of this. But its to the point i cannot cruise far at 65, and when ishut it down i get horrible vapor lock. I have to crank the hell out of it to get it to run, and even then, after hear soak, it wants to stall. I have to blip the gas to keep her going at some red lights. I plan to reroute the fuel line, as right now it passed under the bottom of the disty and rest on the block for a bit before changing to rubber for the rest of the journet to the carb. Any ideas on that too.

Do any of the chain stores have radiators for me? per, autozone, nappa etc?

[wilks3]

The Paddock Parts Co has 3 & 4 core 22" radiators that bolt in. My clutch fan was 3/8" from the rad and would get hotter as you drove down the highway. Took it off just to see, car would not get over 195* with no fan going down the road. A stock 22" shroud woundn't fit new rad because of different top tank used. Don't know if the new shrouds fix this. I made my own out of sheet metal. I used a 16" flexfan with a 1" spacer and made shroud so the blades were half in, half out per Flex-a-lite. Fan is 2" from rad. Got stuck on interstate last summer with no where to get off and car would not get over 210*. Your fuel lines cannot touch any part of engine with todays gas. Buy Edelbrock carb insulator so carb will not heat soak as bad. Did you block off heat cross over on the intake? If not, do so, again because of todays gas. What is your fuel pressure? Stock pump? Make sure timing is right, 30* to 34* total.
Hope this helps.

[Dick]

I shouldn't think that your mods would cause overheating. Your radiator, if original, could very well be partially blocked.

Is your water pump original or has it been replaced? If original, the impeller could be partially corroded away.

[John Kunkel]

What is the history of the fan clutch? Used? New?

Contrary to popular belief a faulty fan clutch can cause overheating at highway speeds.

An old dealer mechanic once showed me how he tests fan clutches. He uses 3/4" masking tape and tapes one fan blade to the shroud, if the clutch is faulty it won't pull the tape loose at idle or slightly above but will cause quite a strong breeze when allowed to run free.

[909duster]

this might sound completely nuts but, I had the same heat up at freeway speeds w/and older 360 in my duster. As you I had a big cooling system, fan and clutch and shroud, an old time mechanic told me to back my timing down and it worked I cannot remeber the settings its been 2 engines ago but I thought he was smoking grass but it sure worked. I don't think mine hit the 230 degree mark.

[superbee1970440]

Kind of a stupid question, but do you have a thermostat installed? Some people believe that removing it will cool the motor but it is not true. You need the resritriction of the thermostat so the coolant has enough time to draw heat out of the motor.

Just a thought....

Sam

[68DCharger383]

Great insight guys. I think i may look into the paddock parts radiator, as today i went for a drive today ( 60 F max air temp ) and the car never went over 200. When it is 30 degrees warmer IE 90 degrees, the car will appraoch the 230 mark, which as you know is at the upper ned of the operating range, and not where you want to be. I think the car respinds best, and start easier when it stays between 180 and 200.

Yes i have a thermostate, and i cant pit anything else under the carb, as the air cleaner is already touching the hood with the high rise intake. Can i run rubber hose right from the mechanical pump outlet up over the passender valve cover and over to the carb inlet? Right now it is solid line bent around the base of the disty cap and does rest on the head for short stink, then inclines up the carb with about another foot of rubber hose. Im more then sure i have a vapor lock issue, and in the summer it is terrible. How can i insulate the line. Is there something i can do ( special hose ) from local stores, IE pep boys autozone etc?

[crisser]

If the cooling system checks out ok, i`d run the car in the condition where it overheats. If safe, i`d cut the engine off and pull over to do a "plug check".
The fuel curve of the carb might be too lean at those rpm`s causing an overheat.

[superbee1970440]

You can run the rubber line like you stated but if you ever want to visit the drag strip, they most likely won't let you run. Tech inspectors do not like to see more than 12 continuous inches of rubber fuel line.

Sam

[68DCharger383]

I am running a carter mechanical (stock type ) fuel pump, which is feeding a EDL 1407 performer carb. The metering rods and jets are all stock, as they are supposed to be idel for the rpm package i installed. I would hope it is not lean. I may have too much timing thought, as when i accelerate moderatley, i do hear some pinging, even with 93 octane. Which way to i turn the allen wrench to back of the rate of advance on the mopar electronic distributor with orange box. what size wrench is it?By the way, ive got too much cam for the streat. I lost some low end for sure, but the 2500 and up range is very nice. I will run rubber line for now, see if can notice a difference with the vapor lock issue. Anyway, ruybber should not soke up the heat as readily as metal lines anyway. It is more of an isulator then metal.

[crisser]

Do a plug check anyway. The engine will tell you if it`s rich or lean. Do it at the speeds that you have problems with. Dark-rich White-lean. Dark specks-detonation = bad. Carbs will run different on different engines. So a buddies engine or a magazine article engine combo will not necesarily run the same as yours. Even if you follow the combo exactly.

[dodger1]

Are you referring to the allen wrench adjustment in the vacuum advance mechanism? If so, that won't affect your initial timing, only the total advance under light-throttle high-vacuum (cruise) conditions. That vacuum line should be connected to the PORTED vacuum source on the carb - not manifold vacuum. Then do the usual timing check with the vacuum advance disconnected and the line plugged. Someone here will know the right baseline numbers for your engine - I only know the small-block stuff. Crisser's advice is also good, and an easy test to do.

[68DCharger383]

You saying i should have my mopar electronic ignition kit with orange box connected to the timed vacuum port? That is to say, no vacumm at idel. I agree, and i must check to see if thats the case. For some reason i think i have it connected to the manifold port. This may be causing the ignition to be too advanced at lower speeds correct?How do i know of my distributor has timed or full vacuum advance?Thanks much man.

[DanL]

If you have it hooked to manifold vacuum while you set it, your basic timing would be late (vacuum advances it, then you turn the distributor to back it down to where you want it).

Late timing causes overheating, too.

Should be connected to ported vacuum, and the hose removed and plugged while setting the timing.

After you set the initial timing, leave the vacuum hose off and run 'er up to 2500 RPM or so while you watch with your light. You'll see if the mechanical advance is working. Then, plug in the hose, and the timing should advance even more.

Some will tell you to leave the vacuum advance unhooked and locked out. I disagree, as long as the distributor is in good shape. It won't hurt you under heavy load, and will help with fuel economy under light load.

[dodger1]

DanL said it. The dist. has both centrifugal (mechanical) advance and vacuum advance. It's the mechanical that should be all in by 2500 which is why it's set with vacuum disconnected and plugged. Somewhere around 32-34 degrees total mechanical - somebody here will correct me if that's not right, then look and see where the initial advance (at idle - no vacuum) winds up. Those numbers will tell you how much mech. advance the dist. has and some recent posts have indicated quite a variation here.

[crisser]

Originally Posted by dodger1

DanL said it. The dist. has both centrifugal (mechanical) advance and vacuum advance. It's the mechanical that should be all in by 2500 which is why it's set with vacuum disconnected and plugged. Somewhere around 32-34 degrees total mechanical - somebody here will correct me if that's not right, then look and see where the initial advance (at idle - no vacuum) winds up. Those numbers will tell you how much mech. advance the dist. has and some recent posts have indicated quite a variation here.

But, when you have a quick mechanical curve plus vacunm advance, the engine will have too much timing at low speeds/high vacumn conditions causing light throttle pinging that goes away when you stomp on it.

[68DCharger383]

Well turns out i do have the hose connected to the manifold port, reason being it says to do so in the Edelbrock manual when using a radical camshaft. Now mines not the most radical, but it is 238/246 with .480/.495 lift @.050", so i thought that fit the bill as radical ( not stock or close to it). So should i set my initial at 15 degrees and move over to the timed vacuum port on the carb? EDL-1407. I am pretty positive i have too much advace under light load and that is causing the detonation. When i givemore fuel, so quites down.

Also, should the 1/4" port on the back be plugged as i do not have power brakes, or should it be connected to the vacuum modulater on the 727 tranny? Maybe this is why my car does not downshift from 3rd to 2nd at all, but only to first when under 5mph.

[dodger1]

Plug the rear port. I didn't know that earlier Torqueflites had a vacuum modulator. My 76 B-van did not, nor do 904s but maybe some did. Also, Try setting the (mech) advance at the 32-34 degree mark/2500-3000 rpm first, and see where the idle advance ends up. If it comes too far back (like less than 5 degrees, for example) then the advance curve is too much. And yes, use ported vacuum so that there's no vacuum advance at closed or light throttle.

[dodger1]

If you haven't already done so, check page 2 of 440dakota's "Major problems...."post from yesterday - similar issues are dealt with

[68DCharger383]

I think Wilks theory is correct. My fan seems to be too close to the rad and at sustained speeds above 60mph the fan itself is actually restricting the air flow through the radiator. My shroud is also partially broken on the bottom and top sides, so its not well sealed around the fan. I can complete the circle of the shroud with some tape and see if that helps. ? how can i move the fan futher from the rad and closer to the engine? RIght now i have about 1/2" clearence at most. Maybeless as the fan belt was hard to sneak passed the fan hub and the radiator.

[Ray Bell]

Move the radiator forward?

[68DCharger383]

I put in a 160, as there was noting there at all, and she still climbs up to 225 in 85 degree weather. Car warms up faster, as is expected with a Tstat, but overall, she still runs hot. Timing is correct. Carb is EDL1407. I heard they run kinda fat out of the box, but i cant say for sure it isnt leane cruising. How many rows is the original radiator, and will a new one with the same amout of rows make a difference, if it is aluminum and not steel, and a cross flow, not a down flow. I think it is safe to say if i can get more surface area exposed to the air, the more cooling i will see. Any suggestions? What did the 440 and hemi use. If they can be cooled, mine surely can.

[plymouth71]

Have you got the cooling problems fixed? I am having the same problems at highway speed 65 mph. On the vapor lock problem have you tried a fuel filter with the vapor outlet.

[70Ted]

i assume he didnt fix it