454 over heating problem
Melting Slicks
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
Where did you hook up the hoses to your mini radiator? I like the idea actually... Mine is working without it with my advanced curve .... But you can never have enough cooling when it's 100*+ and you wand the A/C
I run an ezefi 2.0 and can control the timing via computer 100%... Thus how I have it set up.... I run a light weight high tq mini starter with 11:1 compression and have no problem
I run an ezefi 2.0 and can control the timing via computer 100%... Thus how I have it set up.... I run a light weight high tq mini starter with 11:1 compression and have no problem
You can have a custom radiator built in any size you want ($$) and sneek it for some extra cooling.
My cammed 454 needed a electric 16" running 100% of the time for 200 degrees.
I added a Roots blower, dual Quads, and this extra radiator I do NOT have to run my fan as long as I am moving 30 mph or so.
The air flow on the C-3 is crap according to my measurement device. I mounted meter behind the radiator and drove the car- Not much air flows thru these radiators at all without a factory shroud.
You shouldn't have to add an extra radiator for cooling a stock engine. But who runs stock? This will help pull more air thru the radiator . http://www.ebay.com/itm/69-72-Corvette-014-AC-FAN-SHROUD-EXTENSION-3974014-big-block-427-454-a-c-/110740459033?pt=Vintage_Car_Truck_Parts_Accessories&fits=Model%3ACorvette&hash=item19c8a54e19&vxp=mtrhttp://www.ebay.com/itm/Environment-Meter-Air-Wind-Speed-Velocity-Flow-Meter-Hand-Held-Thermo-Anemometer-/171178015295?pt=US_Weather_Meters&hash=item27db013a3f
Last edited by illenema; Jun 28, 2014 at 06:54 PM.
Thread Starter
Intermediate
Joined: Dec 2011
Posts: 31
Likes: 0
Thanks for all the response. I was able to mess with the timing the other day trying several different combinations. To keep the car cool at idle it defiantly wanted more timeing. I had to hook the vacuum advance up to manifold vacuum to achieve this. The car stays cool at idle. The car heats up the more i drive it. I have to double check but I think the mechanical advance is adding to much timing. Not to the point of detonation but seems high. Above 36 degrees. I will also look for the seals and air dam. Thanks again.
Burning Brakes
Joined: Sep 2012
Posts: 818
Likes: 0
From: coon rapids mn
a thermostat housing that has a radiator cap on top of it ,helps with bleeding air out of the system .I like using a water pump with a turbine impeller .what size are you crank and water pump pulley .what thermostat do you have in the car ?
Safety Car
Joined: Sep 2007
Posts: 4,454
Likes: 328
From: Indy Indiana
remove your thermostat, see if it overheats. that will tell you everything about the capacity of your radiator. Its as simple as that.
A stock system that you state it has, will have plenty of capacity. Standard factory timing and advance curve should be fine also.
You are chasing very low probability reasons. Could be as simple as your gauge is off.
A stock system that you state it has, will have plenty of capacity. Standard factory timing and advance curve should be fine also.
You are chasing very low probability reasons. Could be as simple as your gauge is off.
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
Thanks for all the response. I was able to mess with the timing the other day trying several different combinations. To keep the car cool at idle it defiantly wanted more timeing. I had to hook the vacuum advance up to manifold vacuum to achieve this. The car stays cool at idle. The car heats up the more i drive it. I have to double check but I think the mechanical advance is adding to much timing. Not to the point of detonation but seems high. Above 36 degrees. I will also look for the seals and air dam. Thanks again.
I don't think there is a repro of that special piece...but the AIM has a page showing how it was installed . You can buy some material and make one up .
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Hi,
One thing not mentioned as being replaced, but check the bottom radiator hose for weakness. It should have a spring inside it to keep it from collapsing, since it is on the 'suction side' of the water pump. Warm it up, open the hood, rev the engine and see if it is collapsing. Some newer hoses have no spring and are thicker/more rigid to compensate (this comment could take a disturbing turn right about here). :-) Check that hose.
A C3 big-block WILL run warmer, but should be able to handle warmer temps. However, the closer you are to 100 degrees with the a/c on, the more 'perfect' your cooling system needs to be - hoses, shrouds, seals, radiator condition, etc.
Good luck.
walt z.
One thing not mentioned as being replaced, but check the bottom radiator hose for weakness. It should have a spring inside it to keep it from collapsing, since it is on the 'suction side' of the water pump. Warm it up, open the hood, rev the engine and see if it is collapsing. Some newer hoses have no spring and are thicker/more rigid to compensate (this comment could take a disturbing turn right about here). :-) Check that hose.
A C3 big-block WILL run warmer, but should be able to handle warmer temps. However, the closer you are to 100 degrees with the a/c on, the more 'perfect' your cooling system needs to be - hoses, shrouds, seals, radiator condition, etc.
Good luck.
walt z.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Racer
Joined: Aug 2005
Posts: 355
Likes: 18
From: Corona Ca
Every time I see discussions about overheating in Big Blocks, I think on write-ups I have seen on "Series Flow" and "Parallel Flow" in these engines. Have read that putting gaskets for one type of flow into a motor that should have the other can cause overheating. Could this be the issue?
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
you have air in the system, I fought the same symptom you have have.
I have a a BB with OEM radiator
I filled my system about 6-8 times thinking each time I did a complete job.
each test run the temp would continue to climb. finally got all the air out,
by holding the top radiator hose up in the air while filling.
If your system is working properly get all the air out,
and the Temp will climb right to the T-Stat temperature, and stop there.
another method to ensure the air is out, make sure your radiator overflow tube goes into a catch can,
keep that full the system will suck in liguid and release the air, as it cools back down.
good luck !
I have a a BB with OEM radiator
I filled my system about 6-8 times thinking each time I did a complete job.
each test run the temp would continue to climb. finally got all the air out,
by holding the top radiator hose up in the air while filling.
If your system is working properly get all the air out,
and the Temp will climb right to the T-Stat temperature, and stop there.
another method to ensure the air is out, make sure your radiator overflow tube goes into a catch can,
keep that full the system will suck in liguid and release the air, as it cools back down.
good luck !
Last edited by 69Vett; Aug 6, 2014 at 12:07 PM.
Team Owner
Joined: Jul 2008
Posts: 23,419
Likes: 22
From: In limbo
St. Jude Donor '13-'15, '17 thru '22
Thanks for all the response. I was able to mess with the timing the other day trying several different combinations. To keep the car cool at idle it defiantly wanted more timeing. I had to hook the vacuum advance up to manifold vacuum to achieve this. The car stays cool at idle. The car heats up the more i drive it. I have to double check but I think the mechanical advance is adding to much timing. Not to the point of detonation but seems high. Above 36 degrees. I will also look for the seals and air dam. Thanks again.
FWIW: My car is a '70 454 with AC.
Team Owner
Joined: Oct 1999
Posts: 34,034
Likes: 222
From: Land of Thunder
2018 C2 of Year Finalist
St. Jude Donor '12-'13-'14-'15, '19
so you have had the system apart,... my bet is air in system,
took me about 4 attempts to get ALL air removed.
you will know when the temp gauge stops at your thermostat temperature.
(you do know your Thermostat temp. right ?)
use the radiator hose like a fill hose, holding it up above engine,
let water run out of top radiator hose connection.
you also must verify Every part they gave you is correct.
they can do stupid stuff like give you incorrect parts.
(like incorrect water flow direction in the water pump)
took me about 4 attempts to get ALL air removed.
you will know when the temp gauge stops at your thermostat temperature.
(you do know your Thermostat temp. right ?)
use the radiator hose like a fill hose, holding it up above engine,
let water run out of top radiator hose connection.
you also must verify Every part they gave you is correct.
they can do stupid stuff like give you incorrect parts.
(like incorrect water flow direction in the water pump)
you have air in the system, I fought the same symptom you have have.
I have a a BB with OEM radiator
I filled my system about 6-8 times thinking each time I did a complete job.
each test run the temp would continue to climb. finally got all the air out,
by holding the top radiator hose up in the air while filling.
If your system is working properly get all the air out,
and the Temp will climb right to the T-Stat temperature, and stop there.
another method to ensure the air is out, make sure your radiator overflow tube goes into a catch can,
keep that full the system will suck in liguid and release the air, as it cools back down.
good luck !
I have a a BB with OEM radiator
I filled my system about 6-8 times thinking each time I did a complete job.
each test run the temp would continue to climb. finally got all the air out,
by holding the top radiator hose up in the air while filling.
If your system is working properly get all the air out,
and the Temp will climb right to the T-Stat temperature, and stop there.
another method to ensure the air is out, make sure your radiator overflow tube goes into a catch can,
keep that full the system will suck in liguid and release the air, as it cools back down.
good luck !
Couple questions on your method here: If I'm reading this correctly, you remove the top radiator hose from the radiator side, raise it up and fill. How does this work if the t-stat is closed? And how do you reconnect without losing a bunch of fluid and introducing air back into the system?
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
This method involves hot water use proper precautions. it will flush your system completely.
undo Top hose at radiator, stick water hose in radiator with water running and fill it, let it over flow.
start engine, keep the thermostat radiator hose, up high as possible .
wait until thermostat opens you will know when it opens from lots of water coming out.
Shut off engine, still holding hose up, remove garden hose filling radiator.
do a quick top off off your hose if needed.
now quickly move hose from up position onto the radiator connection.
now, fill / top off your system thru the radiator cap.
your system will actually be over full once you put he cap back on.
next start up/ warm up cycle it will push excess water out of the over flow
even with this method it took a couple attempts.
you will know when you have the air out by the thermostat,
it will stop right at your T-stat temp.and not continue to climb.
After you get the system working with water,
I then drain a gallon of water and replace for antifreeze.
alternate method, install a catch can on the radiator overflow
keep it full, after a couple warmup cylcles the system will suck in liquid and push the air out.
This is how I do it, ... good luck.
undo Top hose at radiator, stick water hose in radiator with water running and fill it, let it over flow.
start engine, keep the thermostat radiator hose, up high as possible .
wait until thermostat opens you will know when it opens from lots of water coming out.
Shut off engine, still holding hose up, remove garden hose filling radiator.
do a quick top off off your hose if needed.
now quickly move hose from up position onto the radiator connection.
now, fill / top off your system thru the radiator cap.
your system will actually be over full once you put he cap back on.
next start up/ warm up cycle it will push excess water out of the over flow
even with this method it took a couple attempts.
you will know when you have the air out by the thermostat,
it will stop right at your T-stat temp.and not continue to climb.
After you get the system working with water,
I then drain a gallon of water and replace for antifreeze.
alternate method, install a catch can on the radiator overflow
keep it full, after a couple warmup cylcles the system will suck in liquid and push the air out.
This is how I do it, ... good luck.
Last edited by 69Vett; Aug 19, 2014 at 12:28 PM.
Burning Brakes
Joined: Oct 2001
Posts: 911
Likes: 5
From: TN
My experience is that improper timing, either too advanced or retarded, can cause the engine to run hot. Timing that's too advanced can cause pre-ignition (pinging if severe, but can be inaudible), which in turn can cause higher combustion chamber temperatures.
Over advanced timing can be caused by improper initial timing, a mechanical advance that's too aggressive, or vacuum advance that's too aggressive. These are often caused by improper adjustment, improper mods (like by-passing TCS using full manifold vacuum), or component wear.
Lars has a great post about distributor wear, which can lead to erratic timing- and overheating:
http://forums.corvetteforum.com/c3-t...e-them-in.html
I'm not a professional mechanic, but I was in my teens and twenties in the 70s-80s when muscle cars were affordable. I didn't have much money for mods, so I focused on the basics: a super tuned ignition and carburetor. I found a few $ spent on fresh plugs, good secondary wiring, coil, cap, rotor, points, condenser, and a properly working distributer not only made a good car run better but often cured other symptoms (over heating, poor gas mileage, starting issues, hesitation, etc.) Once the ignition (and car) is working properly, then spending time on fine tuning the advance curve is one of the most effective yet cheap ways for more power.
This involves a lot of time and experimentation, but it's fun. It's also an example of "wits beats wallet": I would end up with a "stock" engine (stock intake, exhaust, tuned Q-jet) that ran faster, cooler, quieter and more reliably than many of my buddies' cars with a bunch of aftermarket "performannce" mods.
So bottom line: Spend time to find the cause of over heating. This means make sure everything GM installed is working properly (ignition, fuel, radiator seals, fan clutch, radiator, thermostat, air dams, etc.) before adding stuff on your own (like extra coolers or fans). Unless you're racing or have a modified engine, extra stuff isn't needed and may only be compensating for the root cause of the problem.
Over advanced timing can be caused by improper initial timing, a mechanical advance that's too aggressive, or vacuum advance that's too aggressive. These are often caused by improper adjustment, improper mods (like by-passing TCS using full manifold vacuum), or component wear.
Lars has a great post about distributor wear, which can lead to erratic timing- and overheating:
http://forums.corvetteforum.com/c3-t...e-them-in.html
I'm not a professional mechanic, but I was in my teens and twenties in the 70s-80s when muscle cars were affordable. I didn't have much money for mods, so I focused on the basics: a super tuned ignition and carburetor. I found a few $ spent on fresh plugs, good secondary wiring, coil, cap, rotor, points, condenser, and a properly working distributer not only made a good car run better but often cured other symptoms (over heating, poor gas mileage, starting issues, hesitation, etc.) Once the ignition (and car) is working properly, then spending time on fine tuning the advance curve is one of the most effective yet cheap ways for more power.
This involves a lot of time and experimentation, but it's fun. It's also an example of "wits beats wallet": I would end up with a "stock" engine (stock intake, exhaust, tuned Q-jet) that ran faster, cooler, quieter and more reliably than many of my buddies' cars with a bunch of aftermarket "performannce" mods.
So bottom line: Spend time to find the cause of over heating. This means make sure everything GM installed is working properly (ignition, fuel, radiator seals, fan clutch, radiator, thermostat, air dams, etc.) before adding stuff on your own (like extra coolers or fans). Unless you're racing or have a modified engine, extra stuff isn't needed and may only be compensating for the root cause of the problem.
Earlier big block Corvettes used full time vacuum.
3rd Gear
Joined: Nov 2014
Posts: 3
Likes: 0
454 overheating
Thanks for all the response. I was able to mess with the timing the other day trying several different combinations. To keep the car cool at idle it defiantly wanted more timeing. I had to hook the vacuum advance up to manifold vacuum to achieve this. The car stays cool at idle. The car heats up the more i drive it. I have to double check but I think the mechanical advance is adding to much timing. Not to the point of detonation but seems high. Above 36 degrees. I will also look for the seals and air dam. Thanks again.
Racer
Joined: Aug 2005
Posts: 355
Likes: 18
From: Corona Ca
abpost
Can you post pics of the gasket surfaces of your heads and block, which are parallel flow, and the series flow head gaskets?
I have not been able to find pics of these and want to learn what the differences actually look like. Would like to make sure this is at least correct on my big block before I have an issue with it.
Thank you,
Tom
Can you post pics of the gasket surfaces of your heads and block, which are parallel flow, and the series flow head gaskets?
I have not been able to find pics of these and want to learn what the differences actually look like. Would like to make sure this is at least correct on my big block before I have an issue with it.
Thank you,
Tom
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Thanks for all the response. I was able to mess with the timing the other day trying several different combinations. To keep the car cool at idle it defiantly wanted more timeing. I had to hook the vacuum advance up to manifold vacuum to achieve this. The car stays cool at idle. The car heats up the more i drive it. I have to double check but I think the mechanical advance is adding to much timing. Not to the point of detonation but seems high. Above 36 degrees. I will also look for the seals and air dam. Thanks again.
i think I was your first answer:-)
in cruse timing will go well into the high 40's... at WOT it will back down to around 32-34*,,, at least this is how it is supposed to work when operating properly.
people just don't get the timing problems and the heat it makes...
Instructor
Joined: Nov 2005
Posts: 137
Likes: 6
From: Seattle WA
Having owned a '70 non A/C auto coupe and now a '72 L-48 converted to LS-5 all GM, I now conclude that a BB C-3 is loaded with overheating problems. Even if everything is PERFECT as to air dams ,timing, radiator,seals etc. You WILL have overheating problems. If I could have a do over I'd give up on the wow!,cool! factor of the BB and go with the SB hands down. Chasing bad engineering by GM does get really old and exspensive. Have a look at BB problems on this forum, most are overheating problems. See?
SW
SW
