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fan clearance

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
In trying to run cooler than 220 in heavy traffic I thought I would purchase a new shroud since I had the 7 blade stock fan up in the attic. Been running a 12 inch Spal electric puller just up against the radiator with no shroud. Also have a Flowcooler water pump. The fan is still about 1/2 to 3/4 of an inch from even being level with the shroud and at least an inch to inch and a half from being inside the shroud like it should be. Been way to long since I put the electric on to remember how it looked originally. I do know I cored the radiator with the aftermarket flex fan in high water so I know it was closer than it is now. Anyone know what might have caused this? Do they make longer spacers to go between the fan and water pump? This really caught me off guard. The good thing is I found where the radiator is leaking. Fix that and I may be whistling in the wind here.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
Yes, many different sizes of spacers are available. Not sure how many were found on Broncos, but many didn't even come with spacers, so I'm not sure what you need.
Does it heat up at speed too, or just in traffic? Odd, because the electric's strong suit is slower vehicle speeds (check out mduenas' thread about cooling just on this page today) and usually would promote higher temps at speed.
I think that's a thread were there are some pics of fans in their shrouds.

Did your Bronco start to run hot after the fan install? Or was the fan install to remedy an existing issue?
Have you tuned up the engine lately? Checked the timing to make sure it's advancing at higher engine speeds?

Good luck. Nobody likes a hot engine due to rising stress levels as the gauge goes up!
But have you verified the gauge is actually reading correctly?
Luckily, 220 isn't causing damage other than to your heart rate.

Good luck.

Paul
 
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laserfish

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
Found out the radiator was leaking and partially plugged. Had this repaired, put on the new spacer and shroud and had perfect clearance. Started the engine and checked air flow and it was great at all corners, drawing air great across the entire face of the radiator. Let the engine get up to temp and went to check the temp...The needle on my ProComp water temp gauge had FALLEN OFF! Can't anything be easy?? Ordered new gauge to be delivered Friday. Not driving it anyway as it has been raining every day and I currently have not top on. More to follow.
 
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laserfish

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
Paul, you mention that 220 is not causing damage. Being an old guy, you are correct, it does raise my heart rate. What is thought of as "too high". What is ideal for this old but rebuilt 302?
 

DirtDonk

Contributor
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Well, even 240 is not actually ready to seize the engine or anything like that, but at that level I'd sure be looking for a nice shady spot to pull over!;D

I'm not really sure the exact numbers that would create a chart of good-to-bad temps for a given engine. But temps in the 205 to 210 range are, while at the high end of normal, are still considered "acceptable normal" at least for short periods of time. You would not want to see your engine running above that very often without trying to find out why.
At 220 to 230 you're watching the gauge like a hawk to make sure it's not going to keep climbing, but you can still drive it to see if it starts to come down or not.
At 240 you're into the double-secret probation zone, and really don't want to see it go higher so the comment about finding a place to pull over to let it cool down was not a joke.
Over 250 and you really are nearing the true danger zone I think. Not quite at the nuclear meltdown stage, but close enough for government work and you would not want to keep applying a load to the engine or do anything that could potentially cause the engine to heat up even further.
Such as driving it!

Really, at that point you would normally have stopped it so you could eventually check to see if you were not in fact out of coolant, or a fan belt had broken, or something else dire like that had happened.

That's my take on the temp tables anyway. Curious to see what others say.

Paul
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
What the maximum temperature is also depends on whether you are using synthetic oil or not.
Petroleum oils start to break down between 240°F and 275°F depending on additives and base type.
Synthetic oils can easily handle 300°F

Many NASCAR engine builders like to see their engines running between 210°F and 220°F for power output and best oil flow.
 
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laserfish

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
Finally got the new gauge in. Drove around a while then let it sit and idle for 15 minutes. 190 max temp. Amazing what a 1 inch spacer will do for cooling, not to mention making sure the radiator is clean and does not leak. With the fan partially in the shroud, it pulls strong at all 4 corners of the radiator.
 

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DirtDonk

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Bronco Guru
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47,355
You were definitely out of the sweet spot with that earlier setup without the spacer! Even the current setup looks to be just barely in the shroud, but at least it's not completely outside! And you say it's pulling like gangbusters, so that's a win.

So you're saying though, that you added the spacer, AND also changed the temp gauge and sender, AND cleaned the radiator as well? Or was that a typo with the gauge?
I'm sure your spacer is helping a lot, but when changing three things at the same time, it's hard to tell which one did the most, or if all three made the difference.

Glad you posted pics too. Now we can really see how far out that fan was to the shroud. You said it in your first post, but until you see it you really don't have a feel for it.
Spacers don't make all the difference in cooling for everyone, but yours appears to have been a big help.
Glad the changes netted you a win!

Paul
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
You could add an extension to the shroud, something like this:
 

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laserfish

laserfish

Jr. Member
Joined
Feb 19, 2015
Messages
122
The stock setup had a shorter spacer in the first pic. Second pic was with a 2.25 inch scott drake spacer from Summit. They have a 2.5 inch spacer, but with the results I have I think I will stick with the 2.25". Discovered the radiator leak by accident, so I had to have that done. The gauge was replaced because the needle fell off of the original during this ordeal (what timing). Drove it the last two days and most of the time it was at 180*. A couple of times at an extended stop it would almost touch 190*. Am I happy, you bet I am.
Prime example of working on a Bronco. Start on one thing and end up fixing 4 more! It never ends and I love it.
Like the idea of the shroud extension should I ever need it.
 

DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
47,355
They have a 2.5 inch spacer, but with the results I have I think I will stick with the 2.25".

Absolutely! Hey, if it works, it works.

Discovered the radiator leak by accident, so I had to have that done.

Yep. And that by itself was not causing any of the heating issues anyway, unless the slight loss of internal pressure was enough to tip the balance. Which is doubtful...

The gauge was replaced because the needle fell off of the original during this ordeal (what timing).

Oh yeah, saw that mentioned before. These rigs are notorious for "coincidental issues" cropping up.

Drove it the last two days and most of the time it was at 180*. A couple of times at an extended stop it would almost touch 190*. Am I happy, you bet I am.

I call that a big time win!

Paul
 
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