So I recently got my new 383 stroker built at a machine shop and when I put the motor in the car and was ready to drive it, after 15 minutes in the city the coolant temperature kept rising. I had The car idling in the driveway for more than 30 minutes and it’s fine with the temperature steady around 180, but when I drive it the temperature slowly climbs to about 230 until I shut the car off.
here are some details about the car, I have a new high flow water pump from summit, new 4 core rad with dual 12” electric fans and shroud, 180degree thermostat(also tried putting in 160 and 195 still runs hot on the road, I bled the cooling system, air damn under the rad support.
Engine specs: 383 stroker with 248/248solid flat tappet cam, solid lifters, flow teck 220cc 60cc heads, Holley 750DP. If anyone has any ideas or thoughts on y this is happening please let me know I’m open to questions as well.
FYI I’m kinda new to all of this as I’m 20 years old

 

What kinda of timing you running in it?

whats the cruise air fuel ratio look like?

sure you got all the air out the cooling system?


do you still have the air dam under the rad support?

 

Did you purchase really Cheap 12" Electric Fans?

As already said, Air in the Cooling System will cause Over-Heating.

Are you Over-Heating more so at an Idle, or at Expressway Speeds?

Are you using the Heater-Core... or any other External Bypass Configuration.
I now always drill 3 Bleed Holes in the Thermostat, even if there is an External Bypass (I NEVER use the Internal Bypass anymore).

 

Lower air deflector is the 1st thing I'd be looking for

 

If Over-Heating while Expressway Driving...
THIS is a must!!!

 

How much would you lower it?

 

He was talking about (the lower) air dam, not (lowering it).

Also, most new radiators do not come with a new cap and people just tend to use their old ones. These do lose the ability to hold correct pressure. You can check that or just get a new one if you haven't (they're cheap). Also, you mentioned that you have a high flow water pump. Is the thermostat matched to the flow of the pump? If your moving 20% or more volume the manufacturers of these say you need a high flow thermostat to work with it.
(cue the opinions on Hi-Flo's). Since the temp's seem to go out of control while going down the road, the fans/shroud should not be in the equation, they are doing their part when it's idling or at stop n go - this is air flow issue usually. (is the radiator "sealed" on the sides, so that air can't be pushed around the radiator, instead of through it? So, if the air dam is correctly working/radiator "sealed", the system is bled, and the thermostat is doing it's job, Orr's correct in suggesting timing needs checked because that's about all that's left that could be making it run hot unless you have bad parts, castings, blown gaskets, etc. HTH

 

[QUOTE=3rdgenzroc;6475560]He was talking about (the lower) air dam, not (lowering it).

I know. So was I.

 

This is how I managed the engine Temps on my 383 TPI:
https://m.youtube.com/watch?v=27I6xOo4JSw
Good luck and long live TPI!

 

the fans are good, I can have the car idling while hitting the throttle for around 40 minutes and it’s fine, but when I drive the car around the city (stop and go traffic) after 10-15 minutes the temp gauge starts to read hotter and hotter. I bleed the system multiple times even with the front end in the air. Also yes I’m using a heater core. I will drill 3 holes in the thermostat and try that

 

timing is at 32 degrees, and air fuel ratio while driving is at 12. Also I’m sure air is outta the system

 

thanks for the info. The rad I bought came with a cap, and I will give the high flow thermostat a try I have a stock t stay in there right now,and the sides of the rad aren’t sealed, how would I go about sealing it?

 

You say a new water pump?
Is it turning in the correct direction? More than once someone has taken a conventional rotation pump and put it in a serpentine system or vice versa.
Conventional pumps rotate clockwise when viewed from the front. Serpentine (most) rotate counterclockwise.

 

LOL!

 

Go to a hardware store and get a roll of 1"x1" expanding garage door seal tape. I got mine at home depot, they have adhesive already applied and you can keep layering until you fill the gap. This is what I did, and my car stays very cool:

 

[QUOTE=Komet;6476048]Go to a hardware store and get a roll of 1"x1" expanding garage door seal tape. I got mine at home depot, they have adhesive already applied and you can keep layering until you fill the gap. This is what I did, and my car stays very cool:

Was it over heating before you added the foam? What do you have for fans? OE?

 

No, but I had the ac condenser with its foam strips blocking that channel before, so it's doing the same job minus the condenser. I have the stock dual electric fans. Air follows the path of least resistance so if it's easier to go around the radiator than through it, it's gonna do that unless you block it off.

 

Any updates?

 

At the moment I have checked the water pump rotation and it’s good, I put a new high flow thermostat and it had the temp lower but still ends up climbing to around 230 before I shut the car off, there are no air pockets in the system, and I have the black plastic mounted underneath the radiator support. I have also played with timing advancing and retarding and nothing, I pulled the cap off the distributor and noticed one of the contact point in the cap are cracked, I’m getting a new hei distributor since this is an old used one, don’t think this would cause overheating tho. I still haven’t insulated the radiator yet tho, for any other ideas please feel free to ask whatever

 

I also looked into crank pulley to water pump pulley size and it seems fine it’s not 1 to 1 crank is pulley diameter is 7 3/4 water pump pulley diameter is 6 1/4 let me know if this is off