Engine Fan Positioning And Airflow

In my continuing search for cooling fixes, I'm wondering if my fan to shroud positioning matches other member's AMC 304 systems? I have the least fan tip to shroud clearance on top, more on the side and the most on the bottom.








PLUS, my fan throws most air sideways and not so much rearward. As you stand next to a front fender, you can feel the blast of fan airflow. Hold your hand over the engine, behind the fan, and not so much airflow. I can feel a blast of air coming out of this hood hole.

 

You need to move the fan closer to the radiator. Get a spacer.

 

Is that why it's throwing sideways?

 

Probably. You want to get he fan as close as reasonable without hitting the radiator under frame flex and what not. An inch away would probably be fine.

 

Ayuh,..... Agreed,..... Ditch the fan clutch, 'n space the blades closer to the radiator,.....

 

Yes, fan clutch on this era was OEM.

I'll consider getting a spacer.

 

how about moving the shroud back a little?

 

Possibility

 

fan clutches are good they free up alot of hp and noise. I wish i could fit one on my dauntless

 

Along with moving the fan forward, I think you could really benefit from a several inch larger diameter fan. Something that fits the shroud better. I only leave about a 1/2" clearance between the shroud and fan blade tips but that number will be a bit dependent on how stiff the frame and motor mounts are and the resulting flex.

 

It wouldn't be hard to add a strip of aluminum flashing to that shroud...

 

Normally, the fan blade should be 1/2 way inside the shroud. I am not a fan of clutch fans.

 

Weally?

I agree about fan positioning. Half agree about fan clutches.

 

Have we established that there is actually a cooling problem?

 

For me Pete, yes.
Depends on your point of view. 210-215 on my overheating route is too hot for my tastes. I do not care that modern engines are designed to operate at 210F. My 304 is NOT a modern engine. I read the history of that block design and it goes back to the sixties.
So if I allow the engine to continue to operate at those temps, it will crack...somewhere. Others may disagree. That's fine...for their engine.

I made One test drive on my overheating route without the winch cover. 8° warmer ambient than my control drive. 81° outside, no cover and engine temp 195F.

Now the charging system has failed. When I get that fixed, I'll make more test drives and record the ambient plus engine temperature. All testing is being done on the same stretch of highway.

Next potential area of improvement is to temporarily remove the winch and make even more test drives.

 

Respectfully, I'm not sure why or how would happen at 215ºF. Unless all the coolant boiled off first, which it won't with a pressure cap on the radiator.

It is even true that an engine running cool actually suffers increased wear. Why we have thermostats.

"Not a modern engine..." That may be a plus. My 1925 Model T used to boil over every time I came up a steep hill in low gear - with no lasting damage. (Re-coring the radiator fixed that issue.)

 

To be honest, truthful, respectful... I've got a BS in aviation systems, took all the auto and drafting classes I could. Etc etc blah blah blah... 215 is not an issue with iron heads and iron block. If this was an aluminum inline 6 or 8 than warping might be more of an issue but nothing will crack on an Iron engine below 230 unless you let the coolant freeze.
Biggest concern I have in this situation is if there are bubbles in the coolant. Otherwise modern engines are less forgiving.

 

I know this sounds like a jerk answer, but where would you like the air to go after it passes through the radiator and fan? You have what appears to be a belt driven air compressor, electric air compressor, power steering pump, distributor, air cleaner and engine in the pathway of the air travel. It absolutely has to come out the sides and the bottom unless you drill holes in the engine block and front accessories for air flow.
What is this overheating route your speaking of?
A long grade at highway speed or flat land putting around in first gear?
Does it cool off after the route is completed and your driving home?
If your jeep sat and idled for 20 min at 90* outside will it overheat?
If your driving around town does it overheat?
If your driving around town does it overheat?
With the jeep at idle, will it hold a shop towel on the radiator?
If so the shroud is doing its job.
Is the fan clutch engaging at warmer temperatures?
What is your timing set at?
What is the condition of your radiator?
What is the condition of your coolant?
Where is the temperature probe located on the engine that is feeding your gauge?
Have you verified the accuracy of the temperature gauge with heat gun?
210-215 degrees while pulling a grade is quite reasonable and a non issue. As long as you can keep the engine from pushing water out, your not going to hurt it.
195-220 degrees has been the standard since before long your 304 was designed and the temperature should be expected to fluctuate withing that range.
Colder than 195 will actually begin to hurt you more than help and cause problems down the line. Your fuel injection system expects the engine to run 195 and higher as well.

 

What condition is your antifreeze and pressure cap?