Solving an overheat problem
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Joined: Nov 2000
Posts: 11,591
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From: Pflugerville, tx
Sdetweil-
I have just completed Overheating 101 with my truck (1955 F100 390/C6). After reading all the posts, I have one suggestion that wasn’t previously mentioned. Here goes… Is your carburetor running lean? Your idle circuit could have a good A/F mixture thus, you are not overheating when idling in the driveway. However, if you are lean with your primaries this could cause you to run hot as you transition out of the idle circuit into your primaries. This is an easy adjustment to make and could rule out another variable. Just a thought.
Lance
I have just completed Overheating 101 with my truck (1955 F100 390/C6). After reading all the posts, I have one suggestion that wasn’t previously mentioned. Here goes… Is your carburetor running lean? Your idle circuit could have a good A/F mixture thus, you are not overheating when idling in the driveway. However, if you are lean with your primaries this could cause you to run hot as you transition out of the idle circuit into your primaries. This is an easy adjustment to make and could rule out another variable. Just a thought.
Lance
vac secondaries, electric choke.
Sam
More Turbo
Joined: Apr 2007
Posts: 528
Likes: 4
From: Charelston, Illinois
Sam,
I am not familiar with Holley carburetors, but I am sure there are a few experts here on the forum that can explain how to richen up your primaries. If it was an Edelbrock, I could help you.
With my truck, I am running a 1406 Edelbrock carb. I recently took a 400 mile trip and was running hot (my specs: 160 t-stat, flex fan, shroud, dessert cooler stock radiator, transmission cooler). When I got home, I checked the majority of the things previously mentioned on this thread and then went to my local speed shop for suggestions. The suggestion I received after providing them with all the details was to “make sure I wasn’t running lean”. So, like you, I asked how can I do that. They said, Air/Fuel ratio gauge (http://www.summitracing.com/parts/SUM-G2995/ ). I didn’t want to spend the money for the gauge so I bought an Edelbrock Calibration Kit so I could richen up the carb and do the “trial” approach. I changed my step up springs to the next larger size which held my rods up higher resulting in a richer air/fuel mixture. I immediately took the truck out for a long drive with a combination of slow cruising (5-10 mph) as well as highway driving. Believe it or not, my temperature dropped and never got over 180 degrees. I couldn’t believe it!! I have since been driving the truck with no overheating problems (knock on wood).
Lance
I am not familiar with Holley carburetors, but I am sure there are a few experts here on the forum that can explain how to richen up your primaries. If it was an Edelbrock, I could help you.
With my truck, I am running a 1406 Edelbrock carb. I recently took a 400 mile trip and was running hot (my specs: 160 t-stat, flex fan, shroud, dessert cooler stock radiator, transmission cooler). When I got home, I checked the majority of the things previously mentioned on this thread and then went to my local speed shop for suggestions. The suggestion I received after providing them with all the details was to “make sure I wasn’t running lean”. So, like you, I asked how can I do that. They said, Air/Fuel ratio gauge (http://www.summitracing.com/parts/SUM-G2995/ ). I didn’t want to spend the money for the gauge so I bought an Edelbrock Calibration Kit so I could richen up the carb and do the “trial” approach. I changed my step up springs to the next larger size which held my rods up higher resulting in a richer air/fuel mixture. I immediately took the truck out for a long drive with a combination of slow cruising (5-10 mph) as well as highway driving. Believe it or not, my temperature dropped and never got over 180 degrees. I couldn’t believe it!! I have since been driving the truck with no overheating problems (knock on wood).
Lance
Posting Guru
Joined: Jul 2006
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From: Westminster,Md
Sorry..I have no direct experience with your 460/TCI converter/radiator combo..
I would suggest using your new thermometer on your daily driver though,jot down some #'s..temp out of t/stat,across the inlet hose,at the radiator inlet...several points across and down the radiator ,then the outlet back to the engine.
Fans 'on' vs fans 'off {two sets of recordings) ,then compare.
Take a short test drive to get the engine temp 'scenario' that troubles you ..pull-over and do a third set of recordings...information is knowlege. Get some knowns...
I would expect to see at least a 10-15 deg drop in temp from the top of the Radiator and out the bottom( or the other side of rad if a cross-flow). Don't forget to check any by-pass hose temps.
BTW, Lance makes a very good point..leaner = hotter, use your new tool to check header tube temps, cylinder heads etc...
Somehow I see a trans cooler in your future...lol...makes me wonder if the higher converter stall (2200 rpm???) vs the stock 800-900 rpm isn't warming things up a little too much for cruising at slow speeds...If and when you do install a seperate cooler,..checking it's effectiveness will be a breeze with your new tool.I plan on using a 351w/AOD with the same general converter so I'll be watching this thread..thank's for the head's-up and good luck!
I would suggest using your new thermometer on your daily driver though,jot down some #'s..temp out of t/stat,across the inlet hose,at the radiator inlet...several points across and down the radiator ,then the outlet back to the engine.
Fans 'on' vs fans 'off {two sets of recordings) ,then compare.
Take a short test drive to get the engine temp 'scenario' that troubles you ..pull-over and do a third set of recordings...information is knowlege. Get some knowns...
I would expect to see at least a 10-15 deg drop in temp from the top of the Radiator and out the bottom( or the other side of rad if a cross-flow). Don't forget to check any by-pass hose temps.
BTW, Lance makes a very good point..leaner = hotter, use your new tool to check header tube temps, cylinder heads etc...
Somehow I see a trans cooler in your future...lol...makes me wonder if the higher converter stall (2200 rpm???) vs the stock 800-900 rpm isn't warming things up a little too much for cruising at slow speeds...If and when you do install a seperate cooler,..checking it's effectiveness will be a breeze with your new tool.I plan on using a 351w/AOD with the same general converter so I'll be watching this thread..thank's for the head's-up and good luck!
Thread Starter
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Hotshot
Joined: Nov 2000
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Likes: 14
From: Pflugerville, tx
thanks Mertz.. wasn't asking for SPECIFIC 460/C6 temp info, but rather your experience with temp change.. you gave it to me , 10-15 degree change in to out.
this is a 2600 rpm stall converter. so, a bit more than stock at 1000.
yes, with the laser temp should be able to get all kinds of interesting readings..
( I wanted to measure the header temps as I built them and had them coated inside and out)..
too bad on the temp units broad defection angle (8:1).. as I also need to measure a home heat problem but the vent is 20ft up. 3in at 2 ft -> *10 = 30in at 20ft. (want like 4-6in).
Sam
this is a 2600 rpm stall converter. so, a bit more than stock at 1000.
yes, with the laser temp should be able to get all kinds of interesting readings..
( I wanted to measure the header temps as I built them and had them coated inside and out)..
too bad on the temp units broad defection angle (8:1).. as I also need to measure a home heat problem but the vent is 20ft up. 3in at 2 ft -> *10 = 30in at 20ft. (want like 4-6in).
Sam
Thread Starter
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Hotshot
Joined: Nov 2000
Posts: 11,591
Likes: 14
From: Pflugerville, tx
Sam,
I am not familiar with Holley carburetors, but I am sure there are a few experts here on the forum that can explain how to richen up your primaries. If it was an Edelbrock, I could help you.
With my truck, I am running a 1406 Edelbrock carb. I recently took a 400 mile trip and was running hot (my specs: 160 t-stat, flex fan, shroud, dessert cooler stock radiator, transmission cooler). When I got home, I checked the majority of the things previously mentioned on this thread and then went to my local speed shop for suggestions. The suggestion I received after providing them with all the details was to “make sure I wasn’t running lean”. So, like you, I asked how can I do that. They said, Air/Fuel ratio gauge (http://www.summitracing.com/parts/SUM-G2995/ ). I didn’t want to spend the money for the gauge so I bought an Edelbrock Calibration Kit so I could richen up the carb and do the “trial” approach. I changed my step up springs to the next larger size which held my rods up higher resulting in a richer air/fuel mixture. I immediately took the truck out for a long drive with a combination of slow cruising (5-10 mph) as well as highway driving. Believe it or not, my temperature dropped and never got over 180 degrees. I couldn’t believe it!! I have since been driving the truck with no overheating problems (knock on wood).
Lance
I am not familiar with Holley carburetors, but I am sure there are a few experts here on the forum that can explain how to richen up your primaries. If it was an Edelbrock, I could help you.
With my truck, I am running a 1406 Edelbrock carb. I recently took a 400 mile trip and was running hot (my specs: 160 t-stat, flex fan, shroud, dessert cooler stock radiator, transmission cooler). When I got home, I checked the majority of the things previously mentioned on this thread and then went to my local speed shop for suggestions. The suggestion I received after providing them with all the details was to “make sure I wasn’t running lean”. So, like you, I asked how can I do that. They said, Air/Fuel ratio gauge (http://www.summitracing.com/parts/SUM-G2995/ ). I didn’t want to spend the money for the gauge so I bought an Edelbrock Calibration Kit so I could richen up the carb and do the “trial” approach. I changed my step up springs to the next larger size which held my rods up higher resulting in a richer air/fuel mixture. I immediately took the truck out for a long drive with a combination of slow cruising (5-10 mph) as well as highway driving. Believe it or not, my temperature dropped and never got over 180 degrees. I couldn’t believe it!! I have since been driving the truck with no overheating problems (knock on wood).
Lance
Sam
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Joined: Jan 2002
Posts: 583
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From: Augusta, Georgia
You have gotten good council from everyone else; I too believe that, beautiful as it is, the shroud needs to go. It covers a good percentage of the core, which needs air through all of it at highway speeds. HTH
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Hotshot
Joined: Nov 2000
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From: Pflugerville, tx
Sam
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Brett Foote
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Joined: Aug 2001
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From: Glendale, AZ
My vote would also be to remove the shroud and mount fans direct to radiator. Looks like you could do that fairly easily for testing purposes. I also agree with the 10 -15 degree drop across radiator. Higher temp drop = low flow and lower temp drop = high flow. If the waterpump is same as stock you wouldn't think you would have a coolant flow issue tho. Nor can I think of ever seeing a too much coolant flow problem. Usually the rad gets plugged up or waterpump is not moving coolant. Also in your area you can bring your coolant ratio to more like 60/40 or 70/30. Water removes heat better than antifreeze but obviously has no corrossion protection. Possibly check on heat transfer of aluminum rad vs copper???
Posting Guru
Joined: Jul 2006
Posts: 1,276
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From: Westminster,Md
One more thing I thought about..during your testing,pay particular attention to the ' autotrans cooler' portion/area of the radiator for rising temps.Again ,you probably won't see a temp rise at idle in the driveway..but when you go for a slow cruise and your temp starts rising..point the tool at the cooler and see if 'that' temp has climbed too much..40 deg difference? at least at that point you have 'isolated' the problem to the trans fluid. Also the trans cooler lines should be pretty toastie at that point....and from the get-go,the return should be just a little cooler...if your cooler is working.Alot of radiator coolers are not much more than a tube with fins inside the lower tank ,in a 'stock' vehicle...this helps,but in the 'heavy-duty'enviroment, most will agree that removing the cooler from a 180-200 deg liquid saturated enviroment ,redesigning( more fins/tubes) and sticking it in the airstream works better,some have added 'scoops' and/or a small fan...just more ideas....I can hear the gears turning ...
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Joined: Feb 2006
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From: cleveland,Oh.
I have a 3000 stall convertor on my trans c-6 I went with the cooler fan combo. My trans builder told me that my trans will heat up quickly and it does. I can run my engine for around ten minutes and my trans temp is already at 130*, thats sitting in my drive way. I'am using a Hayden Model 526 Rapid cool, and a Hayden temp gauge,these 2 items were money well spent.
Thread Starter
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Hotshot
Joined: Nov 2000
Posts: 11,591
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From: Pflugerville, tx
My vote would also be to remove the shroud and mount fans direct to radiator. Looks like you could do that fairly easily for testing purposes. I also agree with the 10 -15 degree drop across radiator. Higher temp drop = low flow and lower temp drop = high flow. If the waterpump is same as stock you wouldn't think you would have a coolant flow issue tho. Nor can I think of ever seeing a too much coolant flow problem. Usually the rad gets plugged up or waterpump is not moving coolant. Also in your area you can bring your coolant ratio to more like 60/40 or 70/30. Water removes heat better than antifreeze but obviously has no corrossion protection. Possibly check on heat transfer of aluminum rad vs copper???
on the aluminum vs copper.. we couldn't find an aluminum downdraft body to fit the rad U.. and a side draft was too small.. (this based on the limited amount of room I have)..
sam