Cooling help needed

[Doc302]

I just finished installing a rebuilt engine on my 73 mach1 and am having cooling problems. Engine is 429 stroked to 528 and probably is making over 650hp. I have a bigger than stock cam (254/260)so running a bit advanced timing which probably makes it run hotter. Factory radiator, no thermostat ( I am in south Florida so cold starts not a real issue), radiator was rodded. All new hoses, 15lb cap. Dual 11 inch fans 2800 cfm total. Fans start 10 seconds after key on and both run continuously. 50/50 antifreeze and distilled water. C6 transmission with 2600 stall converter, but transmission has separate cooler- fluid not running through radiator. Running 230 after 20-30 min In town driving. Have not driven on freeway yet. I suspect I need a bigger radiator, the make bigger fans, but I don’t think airflow is the problem. Any suggestions on a good radiator for this application. Car is street car with 3-4 runs down the quarter 4-5 times a year. Could timing be enough to make it run this hot? 18 initial/40 total ( I know total is high but it seems to do fine) I can back down , but then it doesn’t like to idle very well/stalls in gear.

 

[cwalker509]

I have a very similar setup in mine but have not started it yet. Dyno time only. I had a well known local shop put mine together. What water pump are you using? My builder strongly recommended the Edelbrock. Not cheap though. I have the dual fans and shroud and separate trans cooler. Many of the aftermarket electric fans are rated rather optimistically. Also using a mech dizzie but only 36 total. Spent a LOT of time on dyno sorting the carb jets. Went thru 3 sets of plugs dialing it in. Have you looked at your plugs? Jetting was all over the map. BT 2x4 intake on mine. Lean can cause hot temps. My engine builder would strongly encourage using a thermostat, probably a 160. Are you running a factory 2 core radiator? I would think 3 core minimum. The early 70s full size Mercury radiators will drop right in.

 

[71coop]

With that many cubic inches I would lean towards water pump flow or radiator size. But just to explore other possibilities - I know you say airflow is not an issue, does that just mean volume? I would also try to make sure as much air as possible is being forced through the radiator from the front, and not being blocked or deflected over the rad. That usually isn't much of an issue in these cars, but after dealing with it in another car, I always check.

Also another thought - I assume those cam numbers are at .050? If so, you probably should be advanced over typical initial stock timing. Too little timing can cause you to run too hot, especially at idle. As long as the timing is not terribly over-advanced, that shouldn't be the issue. What are your compression and initial, total mechanical timing, and vacuum timing advance specs? (Edit - specifically, are you running vac advance & how much. However, I don't think this is your problem).

 

[Tnfastbk]

Start with the easy stuff. Put a thermostat in and see if that changes anything. Make sure the fans are running in the right direction. What was the original radiator for ( 302, 351, etc...). It may end up its just to small.

 

[c9zx]

The timing is OK. Is the lower radiator hose collapsing? Are you sure the head gasket(s) are not on backwards? Just possibilities at this point. Chuck

 

[Kilgon]

The very first thing you should do is put a thermostat in. You are running a continuous loop without giving the water time to transfer its heat to the radiator core for cooling. I would try a 180 first and if that doesn't work go to a 195. A 160 might work but you have to remember that you want to give the water time in the radiator to cool.

 

[Doc302]

I just finished installing a rebuilt engine on my 73 mach1 and am having cooling problems. Engine is 429 stroked to 528 and probably is making over 650hp. I have a bigger than stock cam (254/260)so running a bit advanced timing which probably makes it run hotter. Factory radiator, no thermostat ( I am in south Florida so cold starts not a real issue), radiator was rodded. All new hoses, 15lb cap. Dual 11 inch fans 2800 cfm total. Fans start 10 seconds after key on and both run continuously. 50/50 antifreeze and distilled water. C6 transmission with 2600 stall converter, but transmission has separate cooler- fluid not running through radiator. Running 230 after 20-30 min In town driving. Have not driven on freeway yet. I suspect I need a bigger radiator, the make bigger fans, but I don’t think airflow is the problem. Any suggestions on a good radiator for this application. Car is street car with 3-4 runs down the quarter 4-5 times a year. Could timing be enough to make it run this hot? 18 initial/40 total ( I know total is high but it seems to do fine) I can back down , but then it doesn’t like to idle very well/stalls in gear.

I have a very similar setup in mine but have not started it yet. Dyno time only. I had a well known local shop put mine together. What water pump are you using? My builder strongly recommended the Edelbrock. Not cheap though. I have the dual fans and shroud and separate trans cooler. Many of the aftermarket electric fans are rated rather optimistically. Also using a mech dizzie but only 36 total. Spent a LOT of time on dyno sorting the carb jets. Went thru 3 sets of plugs dialing it in. Have you looked at your plugs? Jetting was all over the map. BT 2x4 intake on mine. Lean can cause hot temps. My engine builder would strongly encourage using a thermostat, probably a 160. Are you running a factory 2 core radiator? I would think 3 core minimum. The early 70s full size Mercury radiators will drop right in.

Thank you for replying, using edelbrock water pump, fans are maradyne with shroud, tune may be a bit lean I am not great at telling lean from good unless very lean. Plan to get wide band o2 sensor to fine tune the carb. Will put in a thermostat first, but sounds like radiator may be next-

 

[Doc302]

The timing is OK. Is the lower radiator hose collapsing? Are you sure the head gasket(s) are not on backwards? Just possibilities at this point. Chuck

Lower hose new and had spring, but I will check it. Reasonably certain head gasket is on correctly, ill probably check that last- thank you for the suggestions

 

[Doc302]

With that many cubic inches I would lean towards water pump flow or radiator size. But just to explore other possibilities - I know you say airflow is not an issue, does that just mean volume? I would also try to make sure as much air as possible is being forced through the radiator from the front, and not being blocked or deflected over the rad. That usually isn't much of an issue in these cars, but after dealing with it in another car, I always check.

Also another thought - I assume those cam numbers are at .050? If so, you probably should be advanced over typical initial stock timing. Too little timing can cause you to run too hot, especially at idle. As long as the timing is not terribly over-advanced, that shouldn't be the issue. What are your compression and initial, total mechanical timing, and vacuum timing advance specs? (Edit - specifically, are you running vac advance & how much. However, I don't think this is your problem).

The very first thing you should do is put a thermostat in. You are running a continuous loop without giving the water time to transfer its heat to the radiator core for cooling. I would try a 180 first and if that doesn't work go to a 195. A 160 might work but you have to remember that you want to give the water time in the radiator to cool.

Thank you will and thermostat

 

[Doc302]

With that many cubic inches I would lean towards water pump flow or radiator size. But just to explore other possibilities - I know you say airflow is not an issue, does that just mean volume? I would also try to make sure as much air as possible is being forced through the radiator from the front, and not being blocked or deflected over the rad. That usually isn't much of an issue in these cars, but after dealing with it in another car, I always check.

Also another thought - I assume those cam numbers are at .050? If so, you probably should be advanced over typical initial stock timing. Too little timing can cause you to run too hot, especially at idle. As long as the timing is not terribly over-advanced, that shouldn't be the issue. What are your compression and initial, total mechanical timing, and vacuum timing advance specs? (Edit - specifically, are you running vac advance & how much. However, I don't think this is your problem).

No vacuum advance 10:1 CR ( calculated not measured) 18 initial plus 22 mechanical. Thank you for your reply

 

[Hemikiller]

As others have said, start with a thermostat, that will help regulate the water flow so that it can cool off in the radiator. If you plan on driving the car a lot, then a 180° is going to get it to temperature more quickly and help burn off any moisture in the oil.

Retarded timing will cause an engine to run hotter, not advanced timing. Your total timing will depend upon a lot of factors. Head chamber design has a significant effect on the total required timing. 40° seems high to me, but I've not built a 385 series for performance. What heads are you running?

 

[Doc302]

As others have said, start with a thermostat, that will help regulate the water flow so that it can cool off in the radiator. If you plan on driving the car a lot, then a 180° is going to get it to temperature more quickly and help burn off any moisture in the oil.

Retarded timing will cause an engine to run hotter, not advanced timing. Your total timing will depend upon a lot of factors. Head chamber design has a significant effect on the total required timing. 40° seems high to me, but I've not built a 385 series for performance. What heads are you running?

I put a 180 degree thermostat in today and idled in gear 40min and only got to 215. Without stat I would have shut down after 20 min at 230. Did not get out on the street today, but thermostat seems to be a big help. I agree 40 degrees seems high, but it seems to tolerate it well. No knocking or pinging. I may restrict the mechanical advance, because it seem to want more initial timing. No dyno near where I live so I will have to travel or the back down initial timing to 12 and add 2 degrees until 1/4 mile trap speed stops going up. Heads are c8ve heads, but have had a lot of port work done. I thought about adding

 

[Doc302]

I put a 180 degree thermostat in today and idled in gear 40min and only got to 215. Without stat I would have shut down after 20 min at 230. Did not get out on the street today, but thermostat seems to be a big help. I agree 40 degrees seems high, but it seems to tolerate it well. No knocking or pinging. I may restrict the mechanical advance, because it seem to want more initial timing. No dyno near where I live so I will have to travel or the back down initial timing to 12 and add 2 degrees until 1/4 mile trap speed stops going up. Heads are c8ve heads, but have had a lot of port work done. Vacuum advance might be my best option for better street manners, but I can not find a distributor for 385 series with vacuum advance and a bronze distributor gear.

 

[Kilgon]

I put a 180 degree thermostat in today and idled in gear 40min and only got to 215. Without stat I would have shut down after 20 min at 230. Did not get out on the street today, but thermostat seems to be a big help. I agree 40 degrees seems high, but it seems to tolerate it well. No knocking or pinging. I may restrict the mechanical advance, because it seem to want more initial timing. No dyno near where I live so I will have to travel or the back down initial timing to 12 and add 2 degrees until 1/4 mile trap speed stops going up. Heads are c8ve heads, but have had a lot of port work done. I thought about adding

You're headed in the right direction. I wouldn't hesitate to put in a 195 and see how that works. For $10 or so it's worth the try. The extra time in the radiator might get you in the 200 to 205 area which would be fine. I think dropping down the initial timing is going in the wrong direction. With the higher compression ratio and bigger cam you are going to want to keep the timing up around 18 or possibly even a little higher. I would take some of the mechanical out so you are in the 34 to 36 range until you get the car tuned in and then work from there.

 

[cjstaci]

It seems to me that with 40 degrees of ignition timing with iron heads running over 200 degrees it would be pinging. I would back your mechanical advance off as stated here previously. Make sure it’s not running lean. Check your spark plugs. If they are clean like new plugs, fatten your mixture 2 jet sizes at a time until you see some color. At 250-260 duration you have pretty healthy cam. Did you degree it in upon installation? I would ask at what rpm does it run smooth ( no lope)? Does the water temperature lower if you run at 3000 rpm or does it go up? When idling with a lot of cam overlap on a 80-90 degree ambient temperature and too small of a radiator, it seems easy for it to run hot.