cooling issue

[belvedere 67]

Im working on a 1941 power wagon project. I put the cab and box on a 1977 dodge 3/4 truck chassis with a 400. Due to the front of the engine compartment being small the radiator i'm forced to used doesnt seem to be able to keep the big 400 cool. I have two electric fans, one on the front pushing air and one on the inside pulling air. I bought the largest radiator that would fit. Would switching to a small block help? I know i could mount a large radiator in the box and plumb in hoses but I really dont want to. Thanks in advance for any help.

 

[diesel_lv]

What size radiator did you put in? A '77 Dodge truck is going to have a larger opening than a '67 B body I suspect. A pusher is not going to help and will be a flow restriction at speed. 2 pullers would be better. But best will always be a mechanical fan w clutch and shroud. Just because it's a truck doesn't make it cool any different than our cars.

 

[diesel_lv]

Sorry, forgot it's the engine compartment of the '41. Still best to use mechanical fan n shroud. Pushers are next to useless.

 

[belvedere 67]

i would like to use a factory fan and shroud but i have about 5 inches from the front of the water pump to the radiator.

 

[Triplegreen500]

I would think the radiator in a '41 would be narrow...but it would be TALL. Should have about the same square footage / frontal area, I would guess...doublecheck your core flow, make sure you don't have a blockage somewhere.

Look for a setup that gives you multiple smaller pullers on the engine side (if you can't fit a belt-driven fan), and leave the grille side open for fresh air. Try a lower thermostat. Also, consider some Water Wetter additive - the stuff works great when I do motorcycle track days and they don't allow traditional glycol coolant on the track (slip hazards). I'll run that, with plain ol' water, and the bike runs street-cool even working it at 110%, WOT all day long.

One change at a time, so you can track what works and what doesn't.

What are you using to reference your temps? Is it a known-good gauge?

You can also consider some louvers on the hood (top and sides), to help vent radiant heat from the engine bay. There's a reason they were popular with hot rodders back in the day! Your '41 doesn't have a cowl gap like newer vehicles do - there's nowhere for underhood heat to escape at the base of the windshield.

If you're running headers, wrap 'em or coat 'em as a last ditch if the above tricks don't do any good. I say last ditch because wrap can make the metal fatigue...and coating is pricey. But...it helps reduce underhood temps quite a bit.

 

[diesel_lv]

i would like to use a factory fan and shroud but i have about 5 inches from the front of the water pump to the radiator.

5 inches is plenty of room for a fan "and" fan clutch. You may have to fab a custom shroud. But a shroud will be worth it no matter what. A 70's 400 will run great w a 180 stat.

 

[belvedere 67]

Is there a higher volume or better flowing than stock water pump for sale out there? I was also thinking about running no thermostate at all. Not using headers.

 

[ESOXER]

Haven't used it but heard good things.
Can't wait to see the truck

https://www.evanscoolant.com/

 

[diesel_lv]

Is there a higher volume or better flowing than stock water pump for sale out there? I was also thinking about running no thermostate at all. Not using headers.

Always use a thermostat. Make sure you have proper pulley ratios. Mechanical fan and shroud. Then start "guessing" if you'd like.

 

[1STMP]

Im working on a 1941 power wagon project. I put the cab and box on a 1977 dodge 3/4 truck chassis with a 400. Due to the front of the engine compartment being small the radiator i'm forced to used doesnt seem to be able to keep the big 400 cool. I have two electric fans, one on the front pushing air and one on the inside pulling air. I bought the largest radiator that would fit. Would switching to a small block help? I know i could mount a large radiator in the box and plumb in hoses but I really dont want to. Thanks in advance for any help.

I'm running a 440 under similar circumstances.
I, like you, have 5" of clearance between the rad
face and WP. I installed a 3000 cfm puller from
Summit that has an included shroud, a 185
deg T-stat, and a 3 core aluminum down flow
w/water wet.
I'm also running a 727 with a 2800 stall conv,
and a fan cooled remote mounted trans oil cooler.
During cam break-in, she never got above 190.

 

[1STMP]

Thought I'd add part/manufacturer numbers
if you think it would help. If you're thinking
about trying a high volume water pump, be
careful and match the volume of coolant
typically for a 400. Faster flow will reduce
the time the coolant is in the radiator, and
may add to the heat problem.
Radiator: Speedway Motors # 9175159
Fan: Summit Racing # FLX-168
Sure hope this helps!

 

[MoparLeo]

Remember that the fans don't mean anything at speeds faster than 45 mph. They are just for low speed airflow through the core. Airflow is what you need to lose the heat . That is what a "radiator" does, transfers heat from the core through the fins to the air.
Fans in front and behind the radiator probably will have the effect of blocking flow. Take the pusher fan off.

 

[1STMP]

I do so humbly apologize. You are correct..
(too many beers?).
I hope the OP understands where I'm coming
from. Went thru lengthy calculations to insure
the 440 stayed cool.. (and it did).

 

[hunt2elk]

I just did some experimenting with the cooling on my 400 based stroker. First went from a stockish PRW pump to a FlowKooler 1679 high volume. This swap really didn't change the operating temps much, but did however drastically lengthen the time it took the motor to creep up to 205* while idling in 90*+ ambient. With the PRW you could watch the gauge quickly go up when I stopped at a light. With the FC it would take 7-8 minutes to do the same. I then swapped out the Stant Super stat 180 for a Milodon 16406 full flow. This change made the biggest impact. Instead of running at 190* while moving, the motor now is 180-185, depending on the ambient temps. I will be installing those 2 items on my other 400 as well.

 

[diesel_lv]

Thought I'd add part/manufacturer numbers
if you think it would help. If you're thinking
about trying a high volume water pump, be
careful and match the volume of coolant
typically for a 400. Faster flow will reduce
the time the coolant is in the radiator, and
may add to the heat problem.
Radiator: Speedway Motors # 9175159
Fan: Summit Racing # FLX-168
Sure hope this helps!

PLEASE Quit giving "Bogus" advice. Coolant does not need to stay in the engine longer to pull heat away. Research science, not a friend of a friend or a car magazine. Research actual thermodynamics. I've got a 4.6 blow through turbo jet boat pushing 700hp at the crank. Engine is under constant load, there is no flat n level cruising in the water, I run 20-30 minutes at 5k rpm w 8psi boost, very extreme conditions. Water is pushed through engine by the jet pump. Never gets above 180°.
I live where it's hot, not Midwest 90's-100's, AZ where we hit mid-hi 120's. My stroke 496 w 2 row aluminum, flowkooler w/p, mechanical fan n shroud w 180 stat keep it at mid 180 on flat n level, mid-upper 190 in town cruising w a/c on and 220 at idle for 10 minutes w a/c after long drive in 125° temps. I believe the Flowkooler is the highest volume pump out there.

 

[1STMP]

PLEASE Quit giving "Bogus" advice. Coolant does not need to stay in the engine longer to pull heat away. Research science, not a friend of a friend or a car magazine. Research actual thermodynamics. I've got a 4.6 blow through turbo jet boat pushing 700hp at the crank. Engine is under constant load, there is no flat n level cruising in the water, I run 20-30 minutes at 5k rpm w 8psi boost, very extreme conditions. Water is pushed through engine by the jet pump. Never gets above 180°.
I live where it's hot, not Midwest 90's-100's, AZ where we hit mid-hi 120's. My stroke 496 w 2 row aluminum, flowkooler w/p, mechanical fan n shroud w 180 stat keep it at mid 180 on flat n level, mid-upper 190 in town cruising w a/c on and 220 at idle for 10 minutes w a/c after long drive in 125° temps. I believe the Flowkooler is the highest volume pump out there.

It's not bogus advice, as it's true to some extent.
High volume pumps work good if most
of your driving is at lower speeds (like crawling
over rocks). It won't fix a overheating problem
on it's own, and I suspect the OP has other
issues such as hot air trapped, or not enough
air flow thru the radiator. I just listed what
worked in my particular case as my Plymouth
truck, and the OP''s Powerwagon are almost
identical in available physical space, and the
powertrain.

 

[Slap Stick]

We never ran stats in 700hp dirt track engines in TX heat. Sometimes we had to block the rad because it wouldn't build enough heat.
If water moves too fast to shed heat it moves too fast to pick up heat.