318 Over Heating (Its Not Mine!)

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805moparkid

805moparkid

Slant and AFX Guy
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So we have this stockish 318 in the 46 truck. One of the smallest comp hydraulic flats (think the 220 cam), 9:1 compression, some blending in the heads with manifolds, Eddy SP-2P intake and 600 holley. Now we have this on going over heating issue that we fix then creeps back.

Symptoms:
In the winter 70* and under the truck does fine.
Once the temp starts to get into the 70-80* range if you pull a hill or turn the A/C on its up in the 200-215* range.
Over 80* you cant run the A/C as its already in the 215* range and will just creep up and up and up.
Cannot bring the timing above 36* (run at 34*)/run vacuum advance or it misfires like crazy, but not ping/knock

What we have done:
Built the truck with the largest possible aluminum radiator, its a 21"x20" (core size) 2 core with a 16lbs cap.
The A/C condenser is mounted 1" off the radiator
Replaced the water pump for a high volume which helped for one week
Greg has a 160* high flow thermostat which again helped for a week
Has a 16" single electric fan with no shroud (no space for another fan or shroud)

Today I pulled the manifold and the intake gaskets are letting a little oil in the ports so they are going to be replaced. Pulled a head and there is a little oil build up in the chambers but not serious, I also checked that the head gasket had holes where it should and it did. Water is traveling thru the block, into the back of the head, then into the manifold in the front.

I think its not enough fan but on the freeway that shouldn't matter, any idea's on whats up?

EDIT: All the front sheet metal is on it.
 

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Age old question Ed, is the bottom hose collapsing? You seem to be having issues when working the engine.
 
Bad Sport said:
Age old question Ed, is the bottom hose collapsing? You seem to be having issues when working the engine.
Click to expand...


i'll ask greg if it has a spring in it or not but to be honest i dont know if he checked that.

thanks for the idea
 
So when it gets hot, how long does it take to come back down to a normal temp if you pull off and sit with it running?

The age-old formula has always been, if it overheats at speed, there's not enough cooling capacity. If it overheats while sitting, not enough airflow capacity.

My feeling is that you simply don't have enough radiator. Remember that most every Mopar with AC used a 26" wide radiator. You may have to figure a way to get a thicker core in there.
 
Bad Sport said:
Age old question Ed, is the bottom hose collapsing? You seem to be having issues when working the engine.
Click to expand...

no dice on the lower

TylerW said:
So when it gets hot, how long does it take to come back down to a normal temp if you pull off and sit with it running?

The age-old formula has always been, if it overheats at speed, there's not enough cooling capacity. If it overheats while sitting, not enough airflow capacity.

My feeling is that you simply don't have enough radiator. Remember that most every Mopar with AC used a 26" wide radiator. You may have to figure a way to get a thicker core in there.
Click to expand...

both lol... it wont come down if you pull off and its to hot at idle. We decided we think the rad is to small to, by moving some stuff around we think we can add 200 sq inches and maybe another fan.
 
After looking at the pic again, is there anything in the nose to direct the air into the radiator? It looks as though a lot of it could be going around it instead of through it.

How about the cap, is it any good?
 
Bad Sport said:
After looking at the pic again, is there anything in the nose to direct the air into the radiator? It looks as though a lot of it could be going around it instead of through it.

How about the cap, is it any good?
Click to expand...

I like Bruce's suggestion. Can you try a makeshift shroud? I would start there.
 
Bad Sport said:
After looking at the pic again, is there anything in the nose to direct the air into the radiator? It looks as though a lot of it could be going around it instead of through it.

How about the cap, is it any good?
Click to expand...

Cap is a new 20lbs.

And yes it is kinda sitting in open territory so i blocked all that off and it helped a little but not near enough.
 
I would think going to 3 row may be in order.
Make sure that fan is wired as a puller and not a pusher.
Hope the after market water pump was not a reverse rotation (magnum) as opposed to a standard rotation (pre-magnum) ....Just throwing ideas out there, good luck.
 
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