427 390 HP Engine Temperature Issues
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427 390 HP Engine Temperature Issues
OK - I'm the GUY that purchased & installed the Ecklers HEI distributor w/ vacuum advance to obtain improved ignition timing which I hoped to lower engine temperatures, for my 1966 427 390 HP Convertible. The HEI was curved 11 dist all in @ 2,800 RPM & 5 dist deg vacuum advance. Initial timing is set @ 14.
The car came w/ a dual point , no vacuum advance, that was scavenged from a 1962 327 - 340HP Vette motor.
Let's take the eBay purchasing of a 40 years old dist & rebuilding it off the table for now! Thanks!
Let's get to the problem:
I purchased the following Infrared Thermometer
http://www.harborfreight.com/cpi/cta...emnumber=93984
The infrared thermometer reads 200 deg & stock gauge read 210 deg which is middle of the gauge. I'm running all stock cooling components with a 160 Mr. gasket high flow Tstat.
How much heat can this motor take?
I would like to see 180 Deg on 93 Octane gas.
Does anyone have a stock 1966 427 390 HP engine that runs in this range.
When I put my hand on the front of the radiator to measure temp it seems to be working fine!
top of the radiator is hot, middle warm, bottom cooler.
The radiator is in excellent shape - Harrison stock brass!
Any suggestions that may help using stock parts?
The car came w/ a dual point , no vacuum advance, that was scavenged from a 1962 327 - 340HP Vette motor.
Let's take the eBay purchasing of a 40 years old dist & rebuilding it off the table for now! Thanks!
Let's get to the problem:
I purchased the following Infrared Thermometer
http://www.harborfreight.com/cpi/cta...emnumber=93984
The infrared thermometer reads 200 deg & stock gauge read 210 deg which is middle of the gauge. I'm running all stock cooling components with a 160 Mr. gasket high flow Tstat.
How much heat can this motor take?
I would like to see 180 Deg on 93 Octane gas.
Does anyone have a stock 1966 427 390 HP engine that runs in this range.
When I put my hand on the front of the radiator to measure temp it seems to be working fine!
top of the radiator is hot, middle warm, bottom cooler.
The radiator is in excellent shape - Harrison stock brass!
Any suggestions that may help using stock parts?
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
OK - I'm the GUY that purchased & installed the Ecklers HEI distributor w/ vacuum advance to obtain improved ignition timing which I hoped to lower engine temperatures, for my 1966 427 390 HP Convertible. The HEI was curved 11 dist all in @ 2,800 RPM & 5 dist deg vacuum advance. Initial timing is set @ 14.
I am guessing. Is your mechanical advance and vacuum advance listed in DISTRIBUTOR DEGREES and the initial in CRANKSHAFT DEGREES?
Race Director
Joined: Jan 2003
Posts: 17,721
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From: Central Arkansas
Your probably as close as your going to get depending on traffic and ambient temperature. Right now my aluminum head, solid lifter 427 runs well below the half way point of the gage and I've checked it with an infrared gun. But in summer, sitting at a long traffic light, it's going to creep up and up until it's a over the half way point and I start looking for some open road. if your car is running around 200 in cool weather on the highway it may be a little warm, but not much. I'm a big believer in vacuum advance. It dropped the temperature on my car big time. If you haven't, you might try a recovery system and reservoir but it probably won't make enough difference to see it on the gage. You might also check out your fan clutch to see if it is working right.
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Your probably as close as your going to get depending on traffic and ambient temperature. Right now my aluminum head, solid lifter 427 runs well below the half way point of the gage and I've checked it with an infrared gun. But in summer, sitting at a long traffic light, it's going to creep up and up until it's a over the half way point and I start looking for some open road. if your car is running around 200 in cool weather on the highway it may be a little warm, but not much. I'm a big believer in vacuum advance. It dropped the temperature on my car big time. If you haven't, you might try a recovery system and reservoir but it probably won't make enough difference to see it on the gage. You might also check out your fan clutch to see if it is working right.
14 crank?
Le Mans Master
Joined: Apr 2004
Posts: 7,106
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From: Newark DE
I caught that too!
If the original rad is still being used that would be the first place I'd start looking at to replace.
After all these years the corrosion build-up inside is enough to greatly diminish cooling capacity.
Time to call DeWitts for a nice aluminum replacement unit.
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Team Owner
Joined: Mar 2003
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From: Greenville, Indiana
OK - I'm the GUY that purchased & installed the Ecklers HEI distributor w/ vacuum advance to obtain improved ignition timing which I hoped to lower engine temperatures, for my 1966 427 390 HP Convertible. The HEI was curved 11 dist all in @ 2,800 RPM & 5 dist deg vacuum advance. Initial timing is set @ 14.
The car came w/ a dual point , no vacuum advance, that was scavenged from a 1962 327 - 340HP Vette motor.
Let's take the eBay purchasing of a 40 years old dist & rebuilding it off the table for now! Thanks!
Let's get to the problem:
I purchased the following Infrared Thermometer
http://www.harborfreight.com/cpi/cta...emnumber=93984
The infrared thermometer reads 200 deg & stock gauge read 210 deg which is middle of the gauge. I'm running all stock cooling components with a 160 Mr. gasket high flow Tstat.
How much heat can this motor take?
I would like to see 180 Deg on 93 Octane gas.
Does anyone have a stock 1966 427 390 HP engine that runs in this range.
When I put my hand on the front of the radiator to measure temp it seems to be working fine!
top of the radiator is hot, middle warm, bottom cooler.
The radiator is in excellent shape - Harrison stock brass!
Any suggestions that may help using stock parts?
The car came w/ a dual point , no vacuum advance, that was scavenged from a 1962 327 - 340HP Vette motor.
Let's take the eBay purchasing of a 40 years old dist & rebuilding it off the table for now! Thanks!
Let's get to the problem:
I purchased the following Infrared Thermometer
http://www.harborfreight.com/cpi/cta...emnumber=93984
The infrared thermometer reads 200 deg & stock gauge read 210 deg which is middle of the gauge. I'm running all stock cooling components with a 160 Mr. gasket high flow Tstat.
How much heat can this motor take?
I would like to see 180 Deg on 93 Octane gas.
Does anyone have a stock 1966 427 390 HP engine that runs in this range.
When I put my hand on the front of the radiator to measure temp it seems to be working fine!
top of the radiator is hot, middle warm, bottom cooler.
The radiator is in excellent shape - Harrison stock brass!
Any suggestions that may help using stock parts?
I don't know if you have the correct radiator or not. Do you?
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Seeing dramatically different temps in different areas of the radiator would be a red flag to me as far as flow.
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I caught that too!
If the original rad is still being used that would be the first place I'd start looking at to replace.
After all these years the corrosion build-up inside is enough to greatly diminish cooling capacity.
Time to call DeWitts for a nice aluminum replacement unit.[/QUOTE]
The current GM Harrison Radiator was purchase from a local Chevy dealer in 1990. Yes, I realize it is 18 years old but it has spent many years out of the car. I flushed it out during a recent engine rebuilt & it was perfectly clean! No rust, just clean antri-freeze. I used a high pressure water nozzle & water flowed through the radiator effortlessly.
Where is the most accurate spot to measure engine temp with the laser thermometer? Base of the brass sending unit? Orange painted Thermostat housing? Black painted Radiator inlet?
Any other way to verfiy water pump & radiator functionality?
Thanks in advance for helping!
Andy
If the original rad is still being used that would be the first place I'd start looking at to replace.
After all these years the corrosion build-up inside is enough to greatly diminish cooling capacity.
Time to call DeWitts for a nice aluminum replacement unit.[/QUOTE]
The current GM Harrison Radiator was purchase from a local Chevy dealer in 1990. Yes, I realize it is 18 years old but it has spent many years out of the car. I flushed it out during a recent engine rebuilt & it was perfectly clean! No rust, just clean antri-freeze. I used a high pressure water nozzle & water flowed through the radiator effortlessly.
Where is the most accurate spot to measure engine temp with the laser thermometer? Base of the brass sending unit? Orange painted Thermostat housing? Black painted Radiator inlet?
Any other way to verfiy water pump & radiator functionality?
Thanks in advance for helping!
Andy
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Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
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Joined: Nov 2008
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6:40 138 178 203 210 118 200 84
6:42 126 197 207 210 141 206 112
6:44 157 200 212 212 126 214 111
6:46 158 203 212 212 147 212 83
6:48 164 202 213 212 149 211 97
6:50 154 202 207 212 140 197 83
6:52 152 201 207 212 140 211 97
6:54 174 209 219 216 160 212 108
6:56 174 209 219 216 160 212 100
6:58 176 213 220 216 166 213 110
Sum 1573 2014 2119 2128 1447 2088 985
Avg 157 201 212 213 145 209 99
Is this motor runnig hot?
The Factory recommends a 195 Deg T-Stat?
Mid gauge - 210 Deg
The avg temp out of the rad is 99 Deg!!
Temp going to heater core is 209 Deg
Gauge & T-Stat are almost the same - maybe the gauge is working!
Even though it never returns to the lowest mark on the gauge.
It seems like everything is working correctly.
However, I would like to see lower tempatures.
Anybody have any info to share on this?
Thanks in advance for helping!
Andy
Last edited by dewhurstaj; Dec 13, 2008 at 02:52 PM. Reason: Easier to read & understand - the columns did not line up.
Race Director
Joined: Jan 2003
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From: Central Arkansas
Team Owner
Joined: Mar 2003
Posts: 26,118
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From: Greenville, Indiana
Does your chart indicate an average of 209* radiator "in" temperature and 99* "out" temperature? If it does, there is nothing wrong with your fan or radiator.
You information kinda' runs together and is hard to decipher but I'll give you credit for much detail.
You information kinda' runs together and is hard to decipher but I'll give you credit for much detail.
Safety Car
Joined: Feb 2000
Posts: 4,977
Likes: 38
From: Massachusetts , USA,
Your probably as close as your going to get depending on traffic and ambient temperature. Right now my aluminum head, solid lifter 427 runs well below the half way point of the gage and I've checked it with an infrared gun. But in summer, sitting at a long traffic light, it's going to creep up and up until it's a over the half way point and I start looking for some open road. if your car is running around 200 in cool weather on the highway it may be a little warm, but not much. I'm a big believer in vacuum advance. It dropped the temperature on my car big time. If you haven't, you might try a recovery system and reservoir but it probably won't make enough difference to see it on the gage. You might also check out your fan clutch to see if it is working right.
My 66 BB , W /alum heads runs cool .....180 thermostat , I actually install a 190 thermostat from Nov to April >>.In my case MSD ignition & pro billet dist, 12 initial 24 Dist (all in 2800 rpm) & full vacume ........Have owned since 1994 never has overheated , I drive minimum 1000 miles a season ....... 
The Dog
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From: Rochester Minnesota
Somethings wrong with your temperature measurements. No way that you get anything close to a 100 degree temperature drop across a radiator. It's been a long time (30+ years) since I was involved in radiator testing, but I recall the temp drops to be more in the area of 10-20 degrees with a good cooling system.
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I edited the data to make it easier to read!
All of the reading were obtained ~1" away from the objects except the radiator temp out which was ~4" but still w/i range of the Infrared Thermometer.
http://www.harborfreight.com/cpi/cta...emnumber=93984
Does anybody know the coolant temp spec of a big block chevy Radiator inlet & radiator outlet?
If the temp data is correct - it seems like it should be more then enough to cool the motor!.
Again! Thanks for helping!
Le Mans Master
Joined: Nov 2000
Posts: 7,246
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From: Going too fast over the hill. Iowa
Somethings wrong with your temperature measurements. No way that you get anything close to a 100 degree temperature drop across a radiator. It's been a long time (30+ years) since I was involved in radiator testing, but I recall the temp drops to be more in the area of 10-20 degrees with a good cooling system.