78 runs too hot
01-16-2019, 06:48 PM
#21
Le Mans Master
Member Since: Aug 2017
Location: Cool Northern Michigan
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Yup. All the way down the foodchain to chipmunks.
After tapping a few curbs in parking lots, I see the owner of that air dam backing into every parking spot forever.
After tapping a few curbs in parking lots, I see the owner of that air dam backing into every parking spot forever.
01-16-2019, 06:55 PM
#22
While i have an 80 and its slightly different to get better cooling i added my own extension on the front air damn using rubber baseboard from home depot for 10 bucks and some bolts. Keeps car a bit too cool at times this past winter in southern california while driving on highway. The rubber flexes plenty while driving over speed bumps etc.
01-16-2019, 07:10 PM
#23
Former Vendor
Member Since: Aug 2006
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You win the prize.. 
Yes, I'm the manufacturer of the extension and most major vendors carry it. It's made right here in the USA! Zip and CC both carry it....
Willcox
Yes, I'm the manufacturer of the extension and most major vendors carry it. It's made right here in the USA! Zip and CC both carry it.... Willcox
Last edited by Willcox Corvette; 01-16-2019 at 07:11 PM.
01-16-2019, 07:26 PM
#25
Le Mans Master
If you have a normal ride height C3, you will have zero issues with the spoiler extension that was a GM option and factory installed in 1979 on L-82's with heavy duty cooling , for the uninformed, from the factory. Keep in mind that the GM piece in my photo and I am sure made by Willcox is FLEXIBLE and designed to retract back if it encounters road debris. I can tell you mine has been on my car for 28 years and I have RARELY had an issue with the stock ride height and the spoiler extension. I repeat, my spoiler extension bought from GM in the late 80's is STILL on the car, undamaged........
In 2015, I did install front springs that were 1 inch shorter than stock and I do have to be more careful now....BUT again, for the misinformed, this piece is FLEXIBLE and will bend back if it encounters a soild object on the road...jeezzzzzz
One last point, the spoiler extension from the 79 L-82's is one of the BEST ways to make our cars run lower normal temps..BY FAR. Most C3's probably could use one but unfortunately, it took the raging hot running 78 L-82's to finally force GM to offer the spoiler extension for the 79 L-82's with heavy duty cooling. I have to surmise that the 80-82's with the revised front facia which incorporated a deep front air dam helped solve the heat issues with the emission clogged engines in 80-82.........without a spoiler extension....
In 2015, I did install front springs that were 1 inch shorter than stock and I do have to be more careful now....BUT again, for the misinformed, this piece is FLEXIBLE and will bend back if it encounters a soild object on the road...jeezzzzzz
One last point, the spoiler extension from the 79 L-82's is one of the BEST ways to make our cars run lower normal temps..BY FAR. Most C3's probably could use one but unfortunately, it took the raging hot running 78 L-82's to finally force GM to offer the spoiler extension for the 79 L-82's with heavy duty cooling. I have to surmise that the 80-82's with the revised front facia which incorporated a deep front air dam helped solve the heat issues with the emission clogged engines in 80-82.........without a spoiler extension....
Last edited by jb78L-82; 01-16-2019 at 07:38 PM.
01-16-2019, 08:48 PM
#26
Le Mans Master
If you have a normal ride height C3, you will have zero issues with the spoiler extension that was a GM option and factory installed in 1979 on L-82's with heavy duty cooling , for the uninformed, from the factory. Keep in mind that the GM piece in my photo and I am sure made by Willcox is FLEXIBLE and designed to retract back if it encounters road debris. I can tell you mine has been on my car for 28 years and I have RARELY had an issue with the stock ride height and the spoiler extension. I repeat, my spoiler extension bought from GM in the late 80's is STILL on the car, undamaged........
In 2015, I did install front springs that were 1 inch shorter than stock and I do have to be more careful now....BUT again, for the misinformed, this piece is FLEXIBLE and will bend back if it encounters a soild object on the road...jeezzzzzz
One last point, the spoiler extension from the 79 L-82's is one of the BEST ways to make our cars run lower normal temps..BY FAR. Most C3's probably could use one but unfortunately, it took the raging hot running 78 L-82's to finally force GM to offer the spoiler extension for the 79 L-82's with heavy duty cooling. I have to surmise that the 80-82's with the revised front facia which incorporated a deep front air dam helped solve the heat issues with the emission clogged engines in 80-82.........without a spoiler extension....
In 2015, I did install front springs that were 1 inch shorter than stock and I do have to be more careful now....BUT again, for the misinformed, this piece is FLEXIBLE and will bend back if it encounters a soild object on the road...jeezzzzzz
One last point, the spoiler extension from the 79 L-82's is one of the BEST ways to make our cars run lower normal temps..BY FAR. Most C3's probably could use one but unfortunately, it took the raging hot running 78 L-82's to finally force GM to offer the spoiler extension for the 79 L-82's with heavy duty cooling. I have to surmise that the 80-82's with the revised front facia which incorporated a deep front air dam helped solve the heat issues with the emission clogged engines in 80-82.........without a spoiler extension....
01-16-2019, 09:03 PM
#27
Le Mans Master
That air dam extension was utilized on 79 L-82's with air IF you didn't get the factory Pace Car spoiler option. I added a Pace car spoiler to my 79 L-82 with air and for whatever reason it didn't have the extension on the previously installed air dam, but once I added the actual Pace car spoiler, it made a significant difference in how cool my car runs. It actually would run hotter on the interstate than slower speeds. To the OP's question, all the bases have been covered here. Seals around the radiator, make sure the bottom hose has a spring in it, make sure the fans are shrouded, make sure there's no air in the system. 230 is definitely warmer than you want to run regularly.
01-16-2019, 09:32 PM
#28
Team Owner
Member Since: Jan 2007
Location: Southern Cal Ca
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St. Jude Donor '22
ask you mechanic what base timing he has it set to.
ask if the distributor has stock "adv curve".
you car was a smog car and the factory specs
will cause your engine to run hot.
depending on his answers, more work may be needed.
ask if the distributor has stock "adv curve".
you car was a smog car and the factory specs
will cause your engine to run hot.
depending on his answers, more work may be needed.
01-16-2019, 10:20 PM
#29
Just FYI- I don't have a special spoiler extension on my 68 and it does NOT overheat.... and I've taken it out in the desert on summer days (well, it doesn't overhead since I've gotten the timing half-azzed correct).
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing through the radiator. I couldn't go much faster or the temperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing through the radiator. I couldn't go much faster or the temperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.
Last edited by carriljc; 01-19-2019 at 01:51 PM.
01-16-2019, 10:41 PM
#30
1st Gear
Member Since: Jan 2019
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Some thoughts
A lean running engine can cause engine over heating. Ignition timiming can also cause it. Over heating can cause run on when the engine is shut off.
i would look at the plugs or find a gas analyzer to check for lean conditions. Are you using the same carb from the 350 engine to feed the larger engine?
i would look at the plugs or find a gas analyzer to check for lean conditions. Are you using the same carb from the 350 engine to feed the larger engine?
01-17-2019, 06:17 AM
#31
Le Mans Master
Just FYI- I don't have a special spoiler extension on my 68 and it does NOT overheat.
What I am saying is that the spoiler extension will INCREASE the cooling efficiency of any year C3...just look at the pictures posted above and logically understand that directing air that normally would flow under a C3 at speed is forced into the gaping holes in the nose towards the radiator...Basic Physics folks and not hard to understand if you think about it for more than a fleeting moment..................Glad this info helped a few folks.
Last edited by jb78L-82; 01-17-2019 at 06:19 AM.
01-17-2019, 08:34 AM
#33
Advanced
Thread Starter
Last call for me on this topic, I am certainly NOT saying that you need the 79 only GM L-82 spoiler extension to ensure that your C3 runs normal temps! Again, the spoiler extension is NOT necessary to achieve a normal operating temp C3.
What I am saying is that the spoiler extension will INCREASE the cooling efficiency of any year C3...just look at the pictures posted above and logically understand that directing air that normally would flow under a C3 at speed is forced into the gaping holes in the nose towards the radiator...Basic Physics folks and not hard to understand if you think about it for more than a fleeting moment..................Glad this info helped a few folks.
What I am saying is that the spoiler extension will INCREASE the cooling efficiency of any year C3...just look at the pictures posted above and logically understand that directing air that normally would flow under a C3 at speed is forced into the gaping holes in the nose towards the radiator...Basic Physics folks and not hard to understand if you think about it for more than a fleeting moment..................Glad this info helped a few folks.
My spoiler below. I’ll post more photos in a few.
01-17-2019, 08:43 AM
#34
01-17-2019, 09:05 AM
#35
Le Mans Master
Nice looking car! The NACA ducts are backwards, and either do nothing, or do the opposite of what you want. Instead of scavenging hot air out of the radiator, they force more air into the engine compartment, limiting flow through the radiator. Or they are purely decorative.
I'm sorry for your loss, and glad to see you are enjoying the car. Hopefully we can help you enjoy it more.
I'm sorry for your loss, and glad to see you are enjoying the car. Hopefully we can help you enjoy it more.
The following users liked this post:
Penelopegirl (01-17-2019)
01-17-2019, 11:52 AM
#36
Drifting
My 78 has a 383 stroker crate engine and Upgraded aluminum radiator with electric fans. After an 18 month upgrade inside and out she’s running beautiful but she’s running hot. Heats quickly to 190-195 and 200. Mechanic reworked the fans and replaced the switch as they were not coming on. Ordered a new thermostat. Today I had her out and up to 225-230 by the time I got home. So not steaming but a bit of diesel when I switched ignition off. Just looking for other experience with these electric fans. What size are you using? These temps in line? I’m old school and they just feel way too hot for me. Appreciate any incite you can add without the insults please. I do have a competent mechanic but he’s a general guy and I’m hoping you guys have more specialty that can help. 
01-17-2019, 01:45 PM
#37
Advanced
Thread Starter
Well until a few days ago she had 15 yo tires, so I was afraid of interstate speeds. So she’s heating in town. After heating in town I’m leary of trying an interstate run. Now new wheels and tires. She’s feeling much better. 🤩
01-17-2019, 01:53 PM
#38
Advanced
Thread Starter
Engine photos
Just FYI- I don't have a special spoiler extension on my 68 and it does NOT overheat.... and I've taken it out in the desert on summer days (well, it doesn't overhead since I've gotten the timing half-azzed correct).
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing the radiator. I couldn't go much faster or the termperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing the radiator. I couldn't go much faster or the termperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.
01-17-2019, 02:12 PM
#39
Race Director
Impressive.
Everything looks to be nicely done.
You definitely need a shroud on the radiator.
Check out DeWitts Radiator.
They are a Forum Vendor, have top quality parts and they can help you get the right shroud.
Plus DeWitts is having a 15% off sale for the next few days.
Do yourself a favor and replace the rubber fuel line with solid tubing.
The slightest fuel leak from the rubber hose could cause a fire.
Everything looks to be nicely done.
You definitely need a shroud on the radiator.
Check out DeWitts Radiator.
They are a Forum Vendor, have top quality parts and they can help you get the right shroud.
Plus DeWitts is having a 15% off sale for the next few days.
Do yourself a favor and replace the rubber fuel line with solid tubing.
The slightest fuel leak from the rubber hose could cause a fire.
Last edited by OldCarBum; 01-17-2019 at 02:17 PM.
01-17-2019, 02:30 PM
#40
Tech Contributor
Member Since: Jun 2004
Location: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Posts: 18,367
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Just FYI- I don't have a special spoiler extension on my 68 and it does NOT overheat.... and I've taken it out in the desert on summer days (well, it doesn't overhead since I've gotten the timing half-azzed correct).
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing the radiator. I couldn't go much faster or the termperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.
I actually drove my car home on the freeway for about 20 miles without the fan working in ~75° outside temperature. I had to stay about 55 mph and the temperature was maintained at 200°F with just the car moving and air flowing the radiator. I couldn't go much faster or the termperature would start rising.
I really think the suggestions to check your timing are the best. Also, you really need to double verify that temperature independently. Here are a couple of bonehead things to check...not trying to insult, but might as well check.
1. Check that you have a normal rotation water pump (you haven't shown us a picture of your belts so we don't know if you have a serpentine belt, or regular belt). If serpentine, then check that you a have a reverse rotation water pump.
2. Ensure the fans are pulling air thru the radiator and not trying to push it forward (I'm assuming you have a puller fan here?)
3. If your temperature indicator is incorrect, then coordinate with Willcox to get that gauge working correctly. I know Willcox makes a fantastic gauge compensator which I installed on my 68.
Just some ideas..... but you really should post some engine compartment pics.