SBC .060 overheating problems. Suggestions please!

[72tutone]

I have researched the site and have googled this topic but I need some real feedback.
I have been trying to break in my new motor. SBC .060 alum heads, edelbrock intake, holley 670cfm.
I'm running into serious overheating problems. I can get to about 5min or so breaking in the cam, and then i get heating problems and it boils out of the rad. I hate keeping to have to stop and start the motor like this. Granted when it does start we have the idle screw cranked up so its not really idling at all.
I have a stant 180 thermostat, stock 3 row rad and a 16" jeep fan with factory shroud. This thing pulls like 3000cfm.
I'm running a serp setup out of a 94 blazer with a new reverse rotation water pump.
I have the fan running all the time and the top hose is getting hot so the thermostat is opening. Just to be sure I boiled it and its opening as it should.
The lower hose isnt collapsing that I can see. I'm not sure what else it could be.
Could the rad be the problem? Ive already taken the water pump back and exchanged it out for a new one. I dont think the stat is the problem, or water pump.
Process of elimination would be the rad. Its a 16lb cap if that makes any difference.

We did have the bypass hose hooked up from the intake to the radiator. Thinking the hot water was running back from the bypass hose back to the rad, we plugged the hole in the intake and then ran the hose from the rad to the water pump. I'm not sure if any of this is necessary or not. I do have a factory AC but its not hooked up at all.

Could the rad be the culprit? Its the only other thing I can think of???

[hugger6933]

My first thought was backwards water pump but from my run ins with that the temp wouldn't jump up until you were like driving in traffic. I wouldn't run hot until you slowed down. Sounds like the rad is the culprit. I would check that next

[72tutone]

Yep, Ive looked at the waterpump description to make sure its the correct rotation.
The donor serp setup is off an 94 s10 blazer. When looking at the setup it should be reverse rotation as the smooth portion of the belt drives the water pump pulley reverse as the crank turns clockwise so I should be ok.

Sanity check here please if I'm wrong.

But yes, the only other thing I can think of is rad. But all this was working fine with the clutch fan prior to me rebuilding it. So I dont know what in the world is happening here.

[Boog]

Bump up the timing. I bet it cools down. 😉

[geezer#99]

I'd suspect your fan choice.
Clutch fan worked good!
Use it instead.
Easy test to see if it's air flow thru the rad.
Set up the biggest fan you can in front of the rad when you fire it up.

[72tutone]

Geezer, this is the fan I'm running.
This thing apparently is to flow upwards of 3600cfm.
It definitely should cool it down. When the motor was running i was pulling in air through the rad with no problems.

[Coley]

Originally Posted by 72tutone

Geezer, this is the fan I'm running.
This thing apparently is to flow upwards of 3600cfm.
It definitely should cool it down. When the motor was running i was pulling in air through the rad with no problems.

A Jeep Fan...correct?
What jeep and what engine was this originally designed to cool?
V6, V8? or?....

All Good
Coley

[72tutone]

From I recall it was a v8 jeep.

Here is the thread that this all started from

http://67-72chevytrucks.com/vboard/s...d.php?t=254617

[WorkinLonghorn]

Not real experienced in heating issues but I once had a cavitation issue with air in the cooling system that the pump couldn't deal with. I think I forced water through the system with a garden hose until all the air was out then added the antifreeze while draining water from the drain cock.
Dumb question, but you are running 50/50 mix right?

[cypressbog]

Did you have a shop remove the radiator tanks and rod it out?

[72tutone]

Originally Posted by cypressbog

Did you have a shop remove the radiator tanks and rod it out?

I have not. My next move was to look at buying a new rad. I'm eliminating all possible issues at this point.

[72tutone]

Originally Posted by WorkinLonghorn

Not real experienced in heating issues but I once had a cavitation issue with air in the cooling system that the pump couldn't deal with. I think I forced water through the system with a garden hose until all the air was out then added the antifreeze while draining water from the drain cock.
Dumb question, but you are running 50/50 mix right?

Yes 50/50 mix.

[trac209]

Try running only water in the cooling system,a garden hose in an open radiator will keep the engine cool but you will get some water on ground in doing so.

[72tutone]

Originally Posted by trac209

Try running only water in the cooling system,a garden hose in an open radiator will keep the engine cool but you will get some water on ground in doing so.

What would this eliminate? The mixture of coolant? I see what your saying Im just trying to understand what would be the result of doing this?

[geezer#99]

So your fan pulls big numbers but only in a 12 inch square area on your rad.
To be effective it needs to be mounted right against the rad, not in your shroud.
You're loosing a bunch of cooling area with that setup.

[72tutone]

So your saying no shroud? I did have to move the fan back within the shroud toward the radiator some more due to clearance issue.
I have always thought when utilizing a pull feature you want the shroud? If I removed the shroud I still have an open area around the fan right? So wouldnt removing it not matter much

[cdowns]

have you ever actually taken the temp with a known good thermometer or you just guessin

[72tutone]

Originally Posted by cdowns

have you ever actually taken the temp with a known good thermometer or you just guessin

I have not, but when its puking out the radiator that doesn't sound good to me. And when my gauge is pegged in red; granted it is the factory gauge that means its running to hot for me. My thermo is 180. So I know its running 200+ for sure.

[hugger6933]

Unless that fan is right up against the core it isn't doing much for you. Mount it close to the rad I mean close like you'd be to your girlfriend. Then cut some cardboard to place around the rest of the rad to act as a temp shroud to test this. With it back away from the rad like that your better off with a fan and clutch set up on there. If you go that way remember it has to turn backwards too, or you WILL overheat.
A fan/clutch of of a 88-95 truck or even an S-10 with the 4.3 would be worth trying. Jim

[72tutone]

Originally Posted by hugger6933

Unless that fan is right up against the core it isn't doing much for you. Mount it close to the rad I mean close like you'd be to your girlfriend. Then cut some cardboard to place around the rest of the rad to act as a temp shroud to test this. With it back away from the rad like that your better off with a fan and clutch set up on there. If you go that way remember it has to turn backwards too, or you WILL overheat.
A fan/clutch of of a 88-95 truck or even an S-10 with the 4.3 would be worth trying. Jim

Hugger, the fan is moved back away from the front of the motor toward the rad. I think the way it is now I have about an 1/8 of an inch between the fan and the rad. I had to move it back within the shroud as the serp setup was hitting the fan in the shroud. If you look at the pic a few replies up, toward the bottom you will see how far it is back from the front of the shroud.

Is there anything else within the heads or gaskets that could be blocking anything? Edelbrock performer RPM intake, Jegs Alum cylinder heads and fel pro 1094 head gaskets. Torqued to spec. I thought the standard SBC 350 didnt have any issues unlike the 400 sbc that had the steam passages etc.