Engine 66 Mustang Coupe, 69 302,Runs hot&overheats,4 row alum rad, 3200 cfm elec fan&shroud,high cap water pump,Still hot,50/50mix,timing ok, runs rich,help!

edgraz66

New Member
Sep 9, 2018
5
1
1
78
Valencia, CA
66Mustang Coupe, 69 302 mild cam, 4 barrel Holley 4160 rebuilt, runs hot and overheats. New 4row alum rad, 3200cfm elec fan and shroud, high cap water pump, trans cooler,50/50mix, timing ok, runs rich, gas smell after running, no gas leaks anywhere. Will rich running cause heated engine? HELP!!!!
 
  • Sponsors(?)


08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
Many minor things can cause these symptoms, More than likely that’s true. Some major things can as well. Sounds like (2) issues.. Is The Overheating portion occur while driving, at idle or both Driving and at Idle?.Does the Car run well when it’s not yet in its high temp.range? Blowing very rich smelling fumes from the tailpipes? Simplest- is you’re Thermostat installed in the right direction, is it opening?, (upper line has flow, you can feel it in the upper Radiator line with your hand, when the Motor hits its normal operating Temperature.)
Is your Timing set with a light, correctly? (Vacuum Advance disconnected)...Have you tried flushing out the Coolant system, Prestone makes a good Cooling System flush, eliminates most possible obstructions.Does the coolant system possibly have trapped air inside; or is vaporlocked?
Try running your Heater on Hot, fan on, full blast- do you get lots of Heat out of the vents? If not, check for an airbound Coolant System, or Heatercore blockage- if you DO blow heat out- does the Car still overheat, or will it level off? BTW:?The Stock Water Pump should be more than adequate in keeping the Engine Cool.
A Rich condition usually won’t cause a Car to run Hot, that’s found more often in lean conditions. A Holley, unsure of the year- has a Powervalve on the Primary Metering Block (Pull off the front Fuel Bowl, and you will be staring at it in the lowercenter of the Metering Block, it’s a small spring assembly with a Diaphragm on back- simply threads in-out, they are inexpensive- replace it if nothing else is found). It controls the low end fuel metering. One backfire through the Carb- or age, will wipe it out & burn your eyeballs out by running too Rich.
I’d take a peek at that, they make new PowerValves that replace the older style and are not so prone to blowout, or you can run a Blank for testing... Ensure the Float level
Overflow Tube(s) are not leaking into the airstream into the Carb, If so, adjust the Float level(s) lower to proper specification.The other common issue with Holleys is the Secondaries are not completely closed, if they’re hanging open- even a tiny bit- extra Fuel will be added into the Mixture and cause a Rich condition... Verify the linkages are allowing 100% closure of the secondaries, even a small piece of Carbon on an offset Throttle Plate can cause this. Verify Accelerator Pump is not leaking into the stream when Throttle is not being actuated. Ensure Choke is wide open.
Check your Oil and Coolant to ensure there is no cross contamination of either, in either. If it’s been running super rich, check the Oil for Fuel
Presence, it can gas wash the Cylinders- not exclusive to the Pistons & Rings, it can also wipe out Main & Rod Bearings much more rapidly.
Replace Oil & Filter if you smell Fuel in your Oil, or it seems thin, or reads high on the stick. Pull & inspect the color of your Spark plugs for evidence of Coolant leakage into Combustion Chamber(s). Do a Compression Test, Cylinders should be within 10lbs of each other. A leak down Test is also another good test to run to locate leak paths.
With the 15lb Coolant Cap ON, you can usually see if Compression is making its way into the Coolant System as it will blow into the recovery Tank very quickly after you start the Motor every time you run it, meaning Combustion pressure is, by some path, leaking into the Coolant system-pressurizing it. & creating excessive heat, A Blown Head Gasket, Cracked Head or Block
are some of the possible Culprits..
Did this occur after you had the Carb rebuilt, engine rebuilt, at what point did it all start To occur? John
 

08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
Many minor things can cause these symptoms, More than likely that’s true. Some major things can as well. Sounds like (2) issues.. Is The Overheating portion occur while driving, at idle or both Driving and at Idle?.Does the Car run well when it’s not yet in its high temp.range? Blowing very rich smelling fumes from the tailpipes? Simplest- is you’re Thermostat installed in the right direction, is it opening?, (upper line has flow, you can feel it in the upper Radiator line with your hand, when the Motor hits its normal operating Temperature.)
Is your Timing set with a light, correctly? (Vacuum Advance disconnected)...Have you tried flushing out the Coolant system, Prestone makes a good Cooling System flush, eliminates most possible obstructions.Does the coolant system possibly have trapped air inside; or is vaporlocked?
Try running your Heater on Hot, fan on, full blast- do you get lots of Heat out of the vents? If not, check for an airbound Coolant System, or Heatercore blockage- if you DO blow heat out- does the Car still overheat, or will it level off? BTW:?The Stock Water Pump should be more than adequate in keeping the Engine Cool.
A Rich condition usually won’t cause a Car to run Hot, that’s found more often in lean conditions. A Holley, unsure of the year- has a Powervalve on the Primary Metering Block (Pull off the front Fuel Bowl, and you will be staring at it in the lowercenter of the Metering Block, it’s a small spring assembly with a Diaphragm on back- simply threads in-out, they are inexpensive- replace it if nothing else is found). It controls the low end fuel metering. One backfire through the Carb- or age, will wipe it out & burn your eyeballs out by running too Rich.
I’d take a peek at that, they make new PowerValves that replace the older style and are not so prone to blowout, or you can run a Blank for testing... Ensure the Float level
Overflow Tube(s) are not leaking into the airstream into the Carb, If so, adjust the Float level(s) lower to proper specification.The other common issue with Holleys is the Secondaries are not completely closed, if they’re hanging open- even a tiny bit- extra Fuel will be added into the Mixture and cause a Rich condition... Verify the linkages are allowing 100% closure of the secondaries, even a small piece of Carbon on an offset Throttle Plate can cause this. Verify Accelerator Pump is not leaking into the stream when Throttle is not being actuated. Ensure Choke is wide open.
Check your Oil and Coolant to ensure there is no cross contamination of either, in either. If it’s been running super rich, check the Oil for Fuel
Presence, it can gas wash the Cylinders- not exclusive to the Pistons & Rings, it can also wipe out Main & Rod Bearings much more rapidly.
Replace Oil & Filter if you smell Fuel in your Oil, or it seems thin, or reads high on the stick. Pull & inspect the color of your Spark plugs for evidence of Coolant leakage into Combustion Chamber(s). Do a Compression Test, Cylinders should be within 10lbs of each other. A leak down Test is also another good test to run to locate leak paths.
With the 15lb Coolant Cap ON, you can usually see if Compression is making its way into the Coolant System as it will blow into the recovery Tank very quickly after you start the Motor every time you run it, meaning Combustion pressure is, by some path, leaking into the Coolant system-pressurizing it. & creating excessive heat, A Blown Head Gasket, Cracked Head or Block
are some of the possible Culprits..
Did this occur after you had the Carb rebuilt, engine rebuilt, at what point did it all start To occur? John
BTW What # Primary Jets are you running?
 

edgraz66

New Member
Sep 9, 2018
5
1
1
78
Valencia, CA
Many minor things can cause these symptoms, More than likely that’s true. Some major things can as well. Sounds like (2) issues.. Is The Overheating portion occur while driving, at idle or both Driving and at Idle?.Does the Car run well when it’s not yet in its high temp.range? Blowing very rich smelling fumes from the tailpipes? Simplest- is you’re Thermostat installed in the right direction, is it opening?, (upper line has flow, you can feel it in the upper Radiator line with your hand, when the Motor hits its normal operating Temperature.)
Is your Timing set with a light, correctly? (Vacuum Advance disconnected)...Have you tried flushing out the Coolant system, Prestone makes a good Cooling System flush, eliminates most possible obstructions.Does the coolant system possibly have trapped air inside; or is vaporlocked?
Try running your Heater on Hot, fan on, full blast- do you get lots of Heat out of the vents? If not, check for an airbound Coolant System, or Heatercore blockage- if you DO blow heat out- does the Car still overheat, or will it level off? BTW:?The Stock Water Pump should be more than adequate in keeping the Engine Cool.
A Rich condition usually won’t cause a Car to run Hot, that’s found more often in lean conditions. A Holley, unsure of the year- has a Powervalve on the Primary Metering Block (Pull off the front Fuel Bowl, and you will be staring at it in the lowercenter of the Metering Block, it’s a small spring assembly with a Diaphragm on back- simply threads in-out, they are inexpensive- replace it if nothing else is found). It controls the low end fuel metering. One backfire through the Carb- or age, will wipe it out & burn your eyeballs out by running too Rich.
I’d take a peek at that, they make new PowerValves that replace the older style and are not so prone to blowout, or you can run a Blank for testing... Ensure the Float level
Overflow Tube(s) are not leaking into the airstream into the Carb, If so, adjust the Float level(s) lower to proper specification.The other common issue with Holleys is the Secondaries are not completely closed, if they’re hanging open- even a tiny bit- extra Fuel will be added into the Mixture and cause a Rich condition... Verify the linkages are allowing 100% closure of the secondaries, even a small piece of Carbon on an offset Throttle Plate can cause this. Verify Accelerator Pump is not leaking into the stream when Throttle is not being actuated. Ensure Choke is wide open.
Check your Oil and Coolant to ensure there is no cross contamination of either, in either. If it’s been running super rich, check the Oil for Fuel
Presence, it can gas wash the Cylinders- not exclusive to the Pistons & Rings, it can also wipe out Main & Rod Bearings much more rapidly.
Replace Oil & Filter if you smell Fuel in your Oil, or it seems thin, or reads high on the stick. Pull & inspect the color of your Spark plugs for evidence of Coolant leakage into Combustion Chamber(s). Do a Compression Test, Cylinders should be within 10lbs of each other. A leak down Test is also another good test to run to locate leak paths.
With the 15lb Coolant Cap ON, you can usually see if Compression is making its way into the Coolant System as it will blow into the recovery Tank very quickly after you start the Motor every time you run it, meaning Combustion pressure is, by some path, leaking into the Coolant system-pressurizing it. & creating excessive heat, A Blown Head Gasket, Cracked Head or Block
are some of the possible Culprits..
Did this occur after you had the Carb rebuilt, engine rebuilt, at what point did it all start To occur? John
 

edgraz66

New Member
Sep 9, 2018
5
1
1
78
Valencia, CA
08GT500,
Thanks for reply!!!
Replaced power valve. Timing off slightly, have corrected. Flushed engine with Prestone product and cleared up using distilled water. Thermostat in correct position-180 degree type with small hole drilled in to help release air. Adjusted carb using vacuum gauge. Heat coming out of heater, engine still gets hot with heater on full blast. Started engine with cap off to eliminate air. Performed gas detection at radiator, was negative.
Engine will sit all day at idle at 180 but take it out for ride temp climbs 20 to 30 plus degrees and more at times. No oil in water, no water in oil!!! Took off front bottom cowling for better air flow, no difference. Engine runs well at all rpm's.
Will perform compression test this coming week. Will also try gas detection again.
Getting frustrated!!!
 

08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
Sorry to hear you’re still fighting that, always welcome for the response! She certainly likes to run warm under a load, I see, lol! It’ll be nailed right quick- no worries..I’d had a thought regarding your fuel pressure, are you certain it’s maintaining between 5 and 8psi at all speeds, maintaining that pressure under all load conditions, because if it drops off at mid-higher rpms (Even Low Float levels, Motor uses more fuel when under a load) running the risk of going lean. ‘Near stock’ Carbureted engines like yours use roughly 14.1:1 to 13.4:1 air/fuel ratio at idle and slightly richer at high rpm’s. Lean will ramp engine heat up very quickly...
I’d prev.asked what #Jets you’re running in your Primaries (?) Pull your Plugs out and read them after a quick cruise. You should be Tan to a little bit of Carbon, White or Ash Color indicates lean, (good charts with pics of Plugs online under various conditions). It won’t hurt you to bump up a couple Jet sizes if need be- for Testing. We can get further into Carb Tuning, should you suspect, or you’re Plugs do read lean.
The other is your dynamic Timing advance rate possibly coming on too steep, so- too much Timing thrown at it too quickly (will still run very well) & also cause sudden uncontrollable Combustion Chamber Temp. spikes similar to what you’re experiencing..What Distributor setup are you running, it have a Centrifugal advance with Springs, weights & Shims to tailor your Timing curve, and also using an adjustable diaphragm Vacuum advance ?
Test it out, Hook up a Timing light- mark the balancer: @ TDC, then idle timing @12 degrees BTDC, then maximum advance @34-36 degrees BTDC. At operating temp and snap the throttle open and see where you are..How fast Timing is coming on in the RPM range is my concern, but too much TOTAL Timing will do the same, verify your Idle @ 12 Degrees BTDC (Or what your target is) & High RPM Max. of 34-36 Degrees BTDC (about right for most near Stock 1960’s Ford V-8’s). If it exceeds that, we should talk Cam Spec’s..
Try holding your throttle at 2,500-3,000RPM’s under no load for 2-3 Minutes & see what your Temperature does in that scenario..btw- Never intending to insult with questions- just trying to help & not overlook menial possibilities - :) . Is there any chance your Fans are not rotating in the correct direction? I’d also verify that you’re pulling a healthy 15-22 Hg’s of Engine Vacuum at Idle..Cam’s not that radical-correct? Post what you find if you’d like, I’ll see it- take it from there...
I like to keep a set of Mechanical Gauges Plate mounted Underhood for Tuning, nothing special- Temp, Oil Pressure, Vacuum- really does come in handy in situ’s like this. Good luck! Cheers!!
 

edgraz1941

New Member
Mar 31, 2010
1
0
1
Oakdale, NY
Sorry to hear you’re still fighting that, always welcome for the response! She certainly likes to run warm under a load, I see, lol! It’ll be nailed right quick- no worries..I’d had a thought regarding your fuel pressure, are you certain it’s maintaining between 5 and 8psi at all speeds, maintaining that pressure under all load conditions, because if it drops off at mid-higher rpms (Even Low Float levels, Motor uses more fuel when under a load) running the risk of going lean. ‘Near stock’ Carbureted engines like yours use roughly 14.1:1 to 13.4:1 air/fuel ratio at idle and slightly richer at high rpm’s. Lean will ramp engine heat up very quickly...
I’d prev.asked what #Jets you’re running in your Primaries (?) Pull your Plugs out and read them after a quick cruise. You should be Tan to a little bit of Carbon, White or Ash Color indicates lean, (good charts with pics of Plugs online under various conditions). It won’t hurt you to bump up a couple Jet sizes if need be- for Testing. We can get further into Carb Tuning, should you suspect, or you’re Plugs do read lean.
The other is your dynamic Timing advance rate possibly coming on too steep, so- too much Timing thrown at it too quickly (will still run very well) & also cause sudden uncontrollable Combustion Chamber Temp. spikes similar to what you’re experiencing..What Distributor setup are you running, it have a Centrifugal advance with Springs, weights & Shims to tailor your Timing curve, and also using an adjustable diaphragm Vacuum advance ?
Test it out, Hook up a Timing light- mark the balancer: @ TDC, then idle timing @12 degrees BTDC, then maximum advance @34-36 degrees BTDC. At operating temp and snap the throttle open and see where you are..How fast Timing is coming on in the RPM range is my concern, but too much TOTAL Timing will do the same, verify your Idle @ 12 Degrees BTDC (Or what your target is) & High RPM Max. of 34-36 Degrees BTDC (about right for most near Stock 1960’s Ford V-8’s). If it exceeds that, we should talk Cam Spec’s..
Try holding your throttle at 2,500-3,000RPM’s under no load for 2-3 Minutes & see what your Temperature does in that scenario..btw- Never intending to insult with questions- just trying to help & not overlook menial possibilities - :) . Is there any chance your Fans are not rotating in the correct direction? I’d also verify that you’re pulling a healthy 15-22 Hg’s of Engine Vacuum at Idle..Cam’s not that radical-correct? Post what you find if you’d like, I’ll see it- take it from there...
I like to keep a set of Mechanical Gauges Plate mounted Underhood for Tuning, nothing special- Temp, Oil Pressure, Vacuum- really does come in handy in situ’s like this. Good luck! Cheers!!
I have timing set at 10 degrees BTDC with vacuum disconnectedock distributor. With vacuum reattached at 2500 to 3000 rpm I am reading about 45 degrees BTDC!!! Looks as though this is where my problem may lie. Rebuilt engine, mild cam, stock distr w/Pertronix. Thanks
 

08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
Glad to help! You should not have your Vacuum advance hooked up when doing the test, it may be in error, Vacuum Advance only adds when the Car is under a load. It’s adds timing as the motor needs it, I.e; Big Hill, hard acceleration. It does not contribute to Total Timing Advance.
I apologize if that was not clear, i’ll Help you set this up if you give me your Cam Spec’s, Compression Ratio. Quickly, I’ll run you by what it entails...
Setting this up is an easy- yet sometimes time consuming process, Driving it & being very conservative with your Timing limit is imperative at first, 20 Deg. Max Advance (or so)- going with Springs to hit your max Advance by 2,500-3,000 & slowly move your Advance up until you begin finding out where the Motor’s “Sweetspot” is. No
Two Motor’s are identical- persay, but with my more “mild” 302’s with 10.0- 10.2:1 C.R.’s I’d run 12-14 initial, and neither was happy with any more that 31 Deg.Total Advance..
It really depends on your Cams specific profile, your Compression Ratio. The more duration and overlap you have, the more initial yet quick and timing it's going to want to be happy, keep Cool- No Ping- Strong power across the range. On the other hand, running higher Compression- you want to run less Advance, tread lighter with incremental changes.
10 Deg. is way too low for most any type of aftermarket performance Cam. Most fairly aggressive Cams will want at least 14 Deg. at idle, and In a middle- class “Street Performance” Driving setup the Motor typically will want all your Advance by around 3,000, a Stock Distributor of a 60’s 302 may not come in full Advance until 3,500-4,000RPM’s.
Without knowing all the specifics, but from your basic’s posted about your setup, I'd go for 12-14 Degrees initial, have all of your Advance in by 2,800- 3,200 RPMs.
An adjustable Vacuum Diaphragm is a great help, Crane Cams sells one, as do a few others..
Hope that helps!!
 

edgraz66

New Member
Sep 9, 2018
5
1
1
78
Valencia, CA
Thanks for your assistance!!!! Engine rebuilt a few years ago with new rods and pistons, mild cam (one above stock), pertronix ignition, 4 barrel Holley 4160. As I said I have the timing at 10 degrees BTDC with vacuum disconnected. With vacuum still disconnected the max advance is about 22 degrees BTDC but with vacuum attached and at about 2500 to 3000 rpm the advance is about 50 degrees. Tried adjusting vacuum with allen wrench turning it clockwise until it stopped but no change in 50 degree mark. Looks as though there is too much advance as you described but wondering if distributor needs to be adjusted with different springs.

Again thank you!!!
 

08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
You’re very welcome. Yes, sounds like you need to put a different limit Bushing in & get your Max Timing limit lowered, then Springs for what RPM it’s done fully delivering your Dynamic Timing. If you Type in “Ford 60’s Distributor Centrifugal Advance Springkit” into Google, you’ll find all the spots that sell what you require with all the various Springs, Bushings, Weights that come in one kit to set all your centrifugal Timing Curve parameters, correctly.
You may also find it helpful to do a Coolant system flush to get anything that may be lingering in the Motor’s Coolant passages-out! lol. If a reputable Shop rebuilt it, they will boil the Block & Heads prior to any Machining or prep.for the Rebuild. I’d be surprised if you didn’t find some..
This is a common problem for the older (Not exclusive to Ford’s only, in any way! lol) 289’s & 302’s, even after a few flushes.. Black Rusty chunks of “who knows what” May continue to ooze its way out of some Blocks. Boiling some of the older Blocks a FEW times may still yield this buildup, and is standard procedure to do it a few times at many reputable Automotive Machine Shops.
That, blown Head Gasket(s) , or Gaskets partially obscuring passages is more common than most would believe, or desire, causing overheating issues. Anyhow- It’s cheap insurance, and is worth doing. If you see any pieces- there’s most certainly more, and it gets anywhere it can, unfortunately. The Coolant Flush materials are available at the Chain- Automotive Stores, Prestone & CLR are a couple brands that have worked well for me.
If you have any questions, or get your Parts and need a hand- feel free to add to the thread, or message me (i’ll See it either way) I’m happy to offer any help I can. Take care, Cheers! John
 

edgraz66

New Member
Sep 9, 2018
5
1
1
78
Valencia, CA
08GT500,
Wanted to let you know that I changed springs, bushings and centrifugal advance. Timing is set at 10BTDC with new springs I am getting 20-21BTDC and with new advance I have it adjusted to 35-36BTDC. Max temp is 195 now with all types of driving. The old centrifugal advance would not adjust at all and that was probably my biggest problem. I want to thank you again for the suggestions and the help. I have been a motorhead longer than I can remember and still love cars. My wife thinks I have never grown up but at my age (77) who cares. By the way I'm giving my 66 to my grandson next May when he graduates college, which was my promise!!! Again, thank you!!! Who says you cannot teach an old dog new tricks!!!
edgraz
 
  • Like
Reactions: 08GT500

08GT500

Active Member
Jul 12, 2018
450
52
38
Massachusetts
08GT500,
Wanted to let you know that I changed springs, bushings and centrifugal advance. Timing is set at 10BTDC with new springs I am getting 20-21BTDC and with new advance I have it adjusted to 35-36BTDC. Max temp is 195 now with all types of driving. The old centrifugal advance would not adjust at all and that was probably my biggest problem. I want to thank you again for the suggestions and the help. I have been a motorhead longer than I can remember and still love cars. My wife thinks I have never grown up but at my age (77) who cares. By the way I'm giving my 66 to my grandson next May when he graduates college, which was my promise!!! Again, thank you!!! Who says you cannot teach an old dog new tricks!!!
edgraz
Hello Ed! Yeah, that sounds better, glad we caught that Timing Advance before it did something serious to the Motor- that was tremendous Heat! excellent!! Glad you are off and Running again!! I hope you have fun with it, and it keeps you and your Wife smilin’. Happy to help, no worries. I’ve been the same Gearhead for all my life, 48 in November here- last real era of the 60’s Cars filled my High School parking lot in 1988’, 4-5 years later the Prices for them went too high to Buy, sell, trade around with, my first Car on the road was a 64’ GTO- total Rust wreck, blown engine- Clutch,!
But it was gleaming its newly sprayed midnight Blue and that 389 was built to the hilt & roaring by my Senior year. I’d had so many 60’s, early 70’s Musclecars, wish I’d hung on to them... oh well! Have many Personal Projects going, run a Tuning Shop- New Cars and old, alike!
Glad to hear I’m not the only one who will never grow up, in that regard..my Wife says I’m only 4 (geez, wish I could do that again, lol!). We never really grow up, our Ladies keep us in check, however!! Passing that Car on will really give your Grandson a Window into the past- that’s awesome!! Wish you well, I’m usually here if you ever want to say “Hi”! Keep it at 65 (in School crossings). Cheers! John
 

Attachments