Overheating issues

[SparkyRnD]

Couple of questions, about when does it overheat:
1. does it overheat when sitting, or when moving (or both)?
2. if it overheats when sitting, does it go down when you start moving?
3. does it overheat below 45mph, above 45mph, or both?
4. does it overheat when driving on the highway?

Each of these things can tell you more info about the possible culprit. Once you reply we can start looking at what may be causing it.

[WorkinLonghorn]

Originally Posted by SparkyRnD

Couple of questions, about when does it overheat:
1. does it overheat when sitting, or when moving (or both)?
2. if it overheats when sitting, does it go down when you start moving?
3. does it overheat below 45mph, above 45mph, or both?
4. does it overheat when driving on the highway?

Each of these things can tell you more info about the possible culprit. Once you reply we can start looking at what may be causing it.

How is 210° overheating? The Thermostat on my 350 is set to 195° as a minimum operating temperature which is less than 1/3 of a gauge. I think overheating is something like 265°. -BA

[BigMike]

Originally Posted by WorkinLonghorn

210° in NOT an overheating problem. Fuel line touching a heater hose or near a header? 210+ is when the problem starts - Nothing near headers

When it won't start for 15 minutes after dying does the accelerator pump in the carb squirt a good stream when hand operated? Yes,
fuel will spray into carb when doen by hand, but drips as well (which I've seen caused too much fuel pressure in videos)

What does the spark look like during this no-start period? Solid blue or orange and weak. I've checked both, when running good and when it dies, strong blue spark

During the no-start period after dying, does it start if you tip in a little gas into the carb? No, it feels like it floods. Just before it dies it runs really rough and I have to peddle the gas to keep it running. Then it just gets worse and dies.

What is the vacuum reading during idle and how does the needle look? -BA Don't remember, will check when I get all the parts I need for the regulator

My response is in red ^

[BigMike]

Originally Posted by truckdude239

have you tried a normal t--stat? i dont understand the whole high flow tstat deals if your coolant is moving to fast though the radiator it will not cool off enough and just keep building heat

Yes, had a standard thermostat in it before trying the high flow. Thought the high flow would help since I have a high volume water pump. Made no difference.

Originally Posted by b454rat

I ran an edelbrock carb on a couple different motors, 2 were 454s, and they didn't over heat. I think one had an issue of flooding because the fuel pressure, but swapped for a Holley. I'd try tuning the carb, lean of course can make a motor run warm.

Once I get all the parts to hook up a regulator I will re-tune and adjust the carb

Originally Posted by SparkyRnD

Couple of questions, about when does it overheat:
1. does it overheat when sitting, or when moving (or both)?
2. if it overheats when sitting, does it go down when you start moving?
3. does it overheat below 45mph, above 45mph, or both?
4. does it overheat when driving on the highway?

Each of these things can tell you more info about the possible culprit. Once you reply we can start looking at what may be causing it.

The few colder days we get in Southern California it runs awesome! As long as the temps stay under 210 it does awesome. When it starts creeping over that then it's no fun anymore. Last time I drove it after having both fans come on at low temps it seemed like over 45 it did fine, but I got in slower traffic and had to drive at 40-45mph and it started getting hot again. The fan controller is set to turn off the fans at 45. It gets hot fairly quickly if I am just sitting in traffic and not moving much (again, result of living in SoCal) Both fans are pullers.

I have nothing but issues if the temps here are 80+ (which is most of the year) no matter what speed I drive

Originally Posted by WorkinLonghorn

How is 210° overheating? The Thermostat on my 350 is set to 195° as a minimum operating temperature which is less than 1/3 of a gauge. I think overheating is something like 265°. -BA

I really wish I knew the answer to this, if I did I wouldn't be here asking for help. I've owned muscle cars and trucks for nearly 40 years and have never had this problem on any other vehicle. Or if I did I was able to fix it easily. I have been fighting this for several years. I built my son a 72 Nova for his 17th birthday. We put a 350 in it & he has nearly the exact same setup as I do with the intake, carb, radiator and fuel pump. We put in a single 15" fan and it never overheats. Why I am having so much trouble with the truck is beyond me.

[homemade87]

This may sound like a stupid question but is the fans running in the right direction . Check air flow to be sure when fans are on .

Also did you buy the radiator and fans and shroud together . If so check between the shroud and radiator to be sure there is no packing/cardboard to block airflow .

Just thinking out loud . These are simple things to check of your list . Its got to be something simple . You have covered most of the bases .

[BigMike]

Originally Posted by homemade87

This may sound like a stupid question but is the fans running in the right direction . Check air flow to be sure when fans are on .

Already covered that, but yes they are both pullers and both come on & off at the selected temps

[PGSigns]

Post some pictures of your engine and your fan setup. Pull the plugs and post some pictures. From your description and what is going on it is lean, the float level may be low and it is vapor locking. On your fans is one set to run all the time and the second one set to come on at like 170? I went through this with my edelbrock and with the heat around here in the summer it would do the same thing. We fattened it up, added a heat shield spacer and ran the fuel level in the bowls up. It did better but never was able to completely stop it in the spring when it would get hot and we were still on winter mix fuel. It also never liked more than 4 psi fuel pressure. It has a holley on it now.
Jimmy

[BigMike]

It's a bit dusty...

[BigMike]

Originally Posted by PGSigns

Post some pictures of your engine and your fan setup. Pull the plugs and post some pictures. From your description and what is going on it is lean, the float level may be low and it is vapor locking. On your fans is one set to run all the time and the second one set to come on at like 170? I went through this with my edelbrock and with the heat around here in the summer it would do the same thing. We fattened it up, added a heat shield spacer and ran the fuel level in the bowls up. It did better but never was able to completely stop it in the spring when it would get hot and we were still on winter mix fuel. It also never liked more than 4 psi fuel pressure. It has a holley on it now.
Jimmy

Initially I had it setup for one to come on at 195 & the other at 210. That didn't work from the get go so I changed it to 185 & 195. Ran that way with the same issues so I never drove for more than about 15 minutes at a time. I recently changed it to 185 for the first fan & 186 for the second fan (although I have relays and 12 gauge wire I didn't want too much load at one time so I staggered them coming on). No difference, still gets up in temps.

I really think it is too much fuel pressure, combined with timing being a little off and it more than likely a little rich. Once I get the regulator mounted and the psi at 5 I will re-time it and re-adjust the carb. It is not a daily driver.

[Hollow65]

Delete.

[68c10airstream]

I was a dealer mechanic when the mechanical fans (without a freewheeling clutch) were the norm and if there was a suspected alternator or water pump slipping i would grab the fan blades and see if i could turn the engine over. If i couldn't the belt was not tight enough. I noticed your alternator looks like it is at the end of the adjustment slot, so try this trick and see what happens. Obviously engine turned off, take a big screwdriver or prybar and wedge it between 2 of the fan bolt heads at the face of the water pump and try to turn the engine over and see if it slips. Good luck!!

[geezer#99]

There is a remote possibility that your lack of inner fenders is contributing to your problem.
The air trapped in the wheel wells doesn’t allow the hot air to escape behind and below the rad.
That’s just a theory developed from when I ran a set up like that with fender well headers on an L-88 in a 56 210. It ran hotter and the lack of inner fenders was thought to be the culprit. I did use a 7 blade fan and shroud which helped somewhat.

Has your truck always been without inner fenders?
Nice lookin’ engine bay btw!!

[WorkinLonghorn]

I think it is time to go through the carb, blow out all the passages and put in a "rebuild" kit. Then change the fuel filter and also the air cleaner.
Forget any talk about fans or overheating because this is CLEARLY NOT the issue.
You should think about losing that air cleaner that sucks up hot air that has gone through the radiator. Even the stock air cleaner was designed to pick up air that had gone AROUND the radiator. Why run hot air into your carb? I know it looks cool and sounds cool but it robs tons of power and I'm sure it contributes to your carb problem. Run a cold air intake or even a stock one for testing, and go through your carb.
If it was running rich from too much pressure you would have sooty plugs and black smoke.

[cadillac_al]

This all sounds like a radiator problem to me. The radiator is new so here we are. I run a 400 sbc in an Impala with a wimpy thin radiator and a flex fan 6 inches behind the radiator with no shroud. My nice temp gauge shows me the temp going up to 210 before the thermostat opens and drops to a perfect 195 and stays there all day. Up here in Maine we get lots of 80 degree days but not a lot of 90's. It runs fine on any hot day we have though.

Nobody wants to change a new radiator so that causes us to do everything else under the sun first. It's like the tire balance threads where nobody wants to hear that it needs new tires but finally new tires will cure it. The only answer that makes sense here is the one nobody wants to hear. Something is not right with that radiator. A good radiator should be able to sit in traffic on a hot day without overheating. If they work fine at 50 mph but not in town, it is usually the radiator. I hate to say it.

If this was happening to me I would have a known good radiator that I could swap in there to try.

[BigMike]

Originally Posted by cadillac_al

This all sounds like a radiator problem to me. The radiator is new so here we are. I run a 400 sbc in an Impala with a wimpy thin radiator and a flex fan 6 inches behind the radiator with no shroud. My nice temp gauge shows me the temp going up to 210 before the thermostat opens and drops to a perfect 195 and stays there all day. Up here in Maine we get lots of 80 degree days but not a lot of 90's. It runs fine on any hot day we have though.

Nobody wants to change a new radiator so that causes us to do everything else under the sun first. It's like the tire balance threads where nobody wants to hear that it needs new tires but finally new tires will cure it. The only answer that makes sense here is the one nobody wants to hear. Something is not right with that radiator. A good radiator should be able to sit in traffic on a hot day without overheating. If they work fine at 50 mph but not in town, it is usually the radiator. I hate to say it.

If this was happening to me I would have a known good radiator that I could swap in there to try.

Radiator has been swapped out twice from the original oem style one I started with.

Installing a fuel regulator definitely helped. It is running a lot smoother now and no more dribbling fuel at idle.
I think from everyone's help as well as researching more into carburetor and fuel I think I have narrowed it down to fuel boiling in the lines. When I run it and it starts acting up I cannot touch the fuel filter because it is way too hot. Then it starts running really rough and wants to die, which it eventually does. All of my lines are far from headers and other direct heat sources but I think that is the issue. I always felt like the engine compartment got super hot so I always assumed it was getting too hot. I think I will try a return line back to the tank. After seeing several videos on the subject it makes sense to me now. I will eventually get rid of the carb and go with an EFI setup so I will need a return line anyways. Another (added) option is to put in an in tank fuel pump that I can either run with the current carb setup and eventual EFI setup. I have seen where that helped the problem further.

[61K10]

Over my many many years of knowledge working on sbc/bbc engines, one thought came up and it's pretty rare. Casting in the water jackets slowing flow? I have heard of this but never had a block that had this problem. Man, you have did everything else!

[BigMike]

Originally Posted by 61K10

Over my many many years of knowledge working on sbc/bbc engines, one thought came up and it's pretty rare. Casting in the water jackets slowing flow? I have heard of this but never had a block that had this problem. Man, you have did everything else!

Not quite everything. I think the return line to the tank and then electric fuel pump will solve it. After spending the last several days online looking at videos of similar issues as mine & what worked for them, I think this is it. There was one cool video where the shop put on a clear fuel line between the filter & carb. You could see after it warmed up good little bubble started appearing in the line. Then the little bubbles went to big bubbles until there was mostly vapor with just a little fuel, all from boiling fuel in the lines. After they put in an electric fuel pump and a return line the bubbles never appeared again and the car ran perfect.

Here is that video. One of several I watched on the subject.

https://www.youtube.com/watch?v=cadNfSNi_Oc

[PGSigns]

The return setup will help a lot. I would also set one fan down to about 130. This will blow air over the motor and help get rid of the heat that is heat soaking your carb. You need some airflow all the time with a carb. The return system will help the fuel temp but you need to give the carb some help also.
Jimmy

[cadillac_al]

I remember a guy having overheating problems when his heater hoses were hooked up wrong. I am not familiar with your water pump set up to know if that hose fitting is an inlet or outlet. Possibly that could be messing with the water flow. Just more food for thought.

[homemade87]

I think I would also relocate or remove the billet fuel filter right behind that fan . I bet that thing really gets heat soaked . In the earlier picture you had it up by the carb which is a better location .

Also that steel braided line does not help either with heat . If you could change it out to a nylon cover it should help . This may get you by until you change to efi .

If mine I would go to a cooler thermostat as well .

[BigMike]

Originally Posted by homemade87

I think I would also relocate or remove the billet fuel filter right behind that fan . I bet that thing really gets heat soaked . In the earlier picture you had it up by the carb which is a better location .

Also that steel braided line does not help either with heat . If you could change it out to a nylon cover it should help . This may get you by until you change to efi .

If mine I would go to a cooler thermostat as well .

I am thinking along these same lines. I will be working on putting together a good quality in tank fuel pump and return lines. I also read the black nylon lines reflect heat better than the stainless ones. I think once I do the electric pump, return lines and the nylon hoses my problems should go away. Carb is adjusted properly and the timing is dead on and the regulator set at 5psi helped a lot as well, truck runs awesome....till the heat attacks the fuel in the lines.

[BigMike]

Okay, putting together my grocery list of items I want. I know I can do it for less $$$ but I want the best for my truck. Going to start with the Aeromotive Stealth 340 in-tank pump. Here is my question. The Aeromotive setup is $487 or so and requires a $58 adapter from Boyd's to make it fit. Boyd's Welding (the tank I have) offers their own mounting setup that bolts right in and uses the Aeromotive stealth pump...and it's only $349. So I will go with the Boyd's setup.

Next I am going to ditch all of the stainless lines and pick up a 20ft roll of Russell Proclassic II black nylon wrapped fuel line and Russell 6-AN fittings. I will plumb it away from all heat sources and up the backside of the engine to a Aeromotive 13301 Universal Bypass Fuel Regulator ($156) and is adjustable from 3-20psi, and then the return line back to the tank. Just have to figure the best location for the filter. The PSI gauge will be right at the input at the carb.

Before your guys help I was asking the wrong questions. I knew 210 wasn't necessarily "overheating" but it was pi$$ing me off that I couldn't fix it. I had done all of the things that I knew worked in the past but have never dealt with vapor lock/heat soak/fuel boil in the lines. Once I started researching those key words I watched video after video, read page after page of my exact symptoms. Since everything else in the truck has been replaced and upgraded, timed, tuned and adjusted, I should never have to worry about getting hot again (knock on wood).

It will take a week or so to get everything in, once I get it all installed I will post an update. Will be amazing to be able to cruise it to car shows all over Southern California without worrying about being stuck on the side of the road.

[geezer#99]

Well at least you haven’t succumbed to ‘Mores Law’ yet. You know that law. If some is good, more is better!
New a guy once who had a bad overheating issue. Everybody told him his rad wasn’t big enough. 2000 bucks later he had a custom 5 core rad. Didn’tchange Nothing.
A 10 dollar air dam under the rad cured it.
Do you have an air dam?
If not research it. It could drop your temp 20 degrees.

[homemade87]

Sounds like a good plan . The in tank pump will make a huge difference . I am sure this will take care of the running problem . But I never liked my SBC to run more that 190 to 195 at the most depending on my engine set up and performance level . They were more happy at around 185 to 190 if not cooler . I would put in a 160 stat and see what the engine does . This may put you in the 180 + range and further better your situation with your environment .

[68gmsee]

Yo, BigMike, I don't have an answer for your problem but I do want to commend you on the pics you have posted. Great looking engine and the pics could help someone wanting to customize their trucks.

I will add that I have fought overheating issues in the past but nothing like you are having. Good luck.