New 351w Running Hot

[73azbronco]

Well opinions are like....

Glad you don't need or want them but they do work.

based on what they work? Proof? What temperature difference was there? Thats my point. Folks do these mods, and more power to you, if you like them, great. I don't think they add any cooling value.

 

[bigmuddy]

based on what they work? Proof? What temperature difference was there? Thats my point. Folks do these mods, and more power to you, if you like them, great. I don't think they add any cooling value.

So you are saying you don't like them...

 

[73azbronco]

No, I am saying i see no proof they work. Long time jeeper here, JK, now JL. Folks do the same to JK/JL's, fender vents, proven they dont lower temperatures. But folks like them because they look good. I'k good, you do you.

 

[Ol'Blue]

Temp gauge is reading higher than it should, so Im going to replace the sender.

I will also go to a 190 or 195* thermostat as suggested by several.

I think one of the reasons Im obsessing over this is my electric booster fan kicking on and thinking its gotta be getting hot.

Changing the electric fan sending unit to 200* will help my sanity as well.

Probably also trim the driver side shroud down a tad.

 

[bigmuddy]

No, I am saying i see no proof they work. Long time jeeper here, JK, now JL. Folks do the same to JK/JL's, fender vents, proven they dont lower temperatures. But folks like them because they look good. I'k good, you do you.

Hmmm, I can only go off of my experience and my experience showed dramatically lower pressures both while when creeping on a trail and after shutdown, which I believe is better for the engine and other underhood components over the long term.

So, since your a long time jeeper how about posting up some evidence from your jeeper days and how it doesn't work on those vehicles?
Seems appropriate considering your statements of how you know they don't work...

 

[73azbronco]

Well, my statement is based on no one providing any proof to the contrary. "it runs cooler" Neat, prove it.

Like I said, if you think it works for you, do it. Your proof is "dramatically lower pressure" What pressure? I am unaware of any air pressure under an EB hood? I thought we were talking temps? Not one person has shown evidence fender wall cutouts lower temps to any statistically meaningful degree. Can you?

 

[DirtDonk]

I don't think anyone needs to prove it any more than you need to. You say it didn't work for you with a Jeep. I don't need proof, because you said it didn't work and I believe you. (usually! )
We're saying it can work on Broncos, and nobody needs to prove it to anyone. Just looking at the cooler temps (when it worked) would be enough for them to be fans of the methods. If they say it worked for them, I believe it.
If they say it did not work for them, I believe them too. But something not working for one does not negate the positive results of others. Never has...
Do all these solutions work every time for everyone? Certainly not! But they've worked often enough over the years, for enough people, that we know that they can work.

I can't help but think that the aerodynamics under the hood of a Jeep are far different from those of a Bronco. I don't know it, but it feels right to say it.
And I can't remember any great lengthy discussions on Jeep forums or among Jeep friends about overheating at trail speeds. Sure, it happens there too. But not nearly as often as we heard it about Broncos. So there seems to be a distinct difference in cooling performance on the trails.
And to this day, I've never seen a Jeep that needed it's hood removed and strapped to the roof to keep the engine cool on the trail. Yet I've seen Bronco hoods strapped up top since the early seventies.
Something is different between the two vehicles then. Engine performance? Engine cooling system design? Cooling capacity? Fan performance? Aero under the hood? All of the above?

Does opening the fenders, or hood, or ducting the radiator, or adding capacity, or changing design and materials, changing fan types, always help keep a Bronco cooler? Nope, we've seen plenty of discussions about how electric fans were not enough, bigger radiators were not enough, baffling and ducting the fans were not enough, changing engine tune was not enough, changing gearing, or transmission cooling methods were not enough. to know that the cure for one does not work for another.
But to make a blanket statement of disbelief does not make sense. If someone said it worked for them, why try to say they're wrong?
If it did not work for another, or perhaps did not work for you, then you did not have the same problem or did not have the same setup.
Every Bronco is STILL different!

Speaking of disagreeing, a double or triple-pass radiator does not impede coolant flow to the point that it hurts performance. I traded a standard heavy duty 4-row radiator for a triple-pass without doing anything else and my temps dropped immediately. Of course, it stopped leaking too, which was really the only reason I changed the radiator in the first place. I wasn't overheating, just leaking. But the new one ran cooler without a doubt.
Was it just the radiator? Can't say, as the temps don't even come up to the thermostat rating anymore. So maybe at the same time I changed the radiator, my thermostat decided to get stuck? Maybe, and I'm always going on about "coincidental failures" happening with our rigs.
The multi-pass radiators were designed way back and probably by racers to meet a certain criteria. Still use them I think, but maybe they found it does slow down flow too much for their liking? Don't know, since I don't hang out in racing circles much anymore.
To my knowledge though, I've never heard of one creating a heating issue where it did not exist before.
No matter though, since I'M happy with mine. Other's results may vary however.

Paul

 

[73azbronco]

You do you, and enjoy it because that's the bottom line.

As an aeronautical engineer, I do however have a tad bit of knowledge in physics and thermodynamics, oh, and aerodynamics. Sort of a show me state mentality.

You are correct, jeep and EB are very different, the aero under a jeep hood is horrible compared to an EB, which has far more space allowing airflow. Lots of room around an EB engine, I can't even get a hand down the side of my 3.6. That's my bases for saying, cutting fenders does not give measurable differences, in a jeep, you just remove the plastic liner, walla, no difference when I tried it, none. All the folks who have said cut fenders on this forum to my memory have also done 3 or 4 other mods (new rad, water pump, shroud, etc) and add the fender cutouts. Correlation does not imply causation.

This sort of ties in with the hood shroud above the core support blocking air under the hood into the radiator, we have shown that works for some by directing more airflow into radiator instead of around and behind it resulting in blocked radiator flow. That mod, an OEM mod, works. I do not have that installed yet, but I will someday.

If ventilating inner fenders works, why are no OEM vehicles vented? I am not talking disk brake vents. If it worked, would that not mean a lower need for a big radiator, big fan, big water pump?

Finally, I am not telling anyone not to cut their inner fender, Some have done a good job making it look good. I am just saying why I won't, I have not seen any proof it works.

We are a grouping of like minded individuals who all have valuable insights and opinions, beer time?

 

[gnpenning]

Wait, what?? You are comparing a modern jeep engine bay to a EB?? That's like a apple to grapes comparison. Your late model jeep would be better compared to a 6g bronco and a 70s era jeep to a EB. More than a few items different.

 

[BroncoJimbo]

Did we already talk about 351 Windsors and over boring?
Seems like we did and you came back with that it wasn’t heavily overbored, and that they did check the cylinder wall thickness?

Not always true. I have been running a 0.060 351W for 20 years and 75K miles. Runs cool even in the GA summers. No other cooling tricks besides the 7 blade fan and the shroud.

 

[DirtDonk]

Correct. It’s not always true. We’ve heard of plenty that have had no trouble. But quite a few more that have.
Unfortunately it’s true often enough that the only safe way to bore more than .040 is to have the cylinder walls sonic checked. Same for lots of motors, but the 351 seems to be high on the list.
If you have a 351 Windsor bored .060 without checking, and it works out just fine, you got one of the good ones and are lucky enough not to have to deal with core shift.
For all we know, there were far more good ones than bad ones, and we only hear about the bad ones.
But that’s not something best left to guessing and hoping for luck. Should still be checked.
I’m sure there are plenty of good ones out there that won’t have trouble going 60 over.
But just like we’ve been talking about here previously, we can’t just ignore or dismiss the experiences that many have.

 

[Ol'Blue]

Thanks for all the "passionate" input gents!

The motor was out of an extremely low mileage F150 lighting. No boring, just freshened up.

 

[DirtDonk]

Sounds like a good place to start!
What kind of original mileage?
Did they ever supercharge the 5.8 in the Lightning? Or was that just for the overhead cam engines?

 

[DirtDonk]

Just reread part of your first post and wanted to touch on something that was brought up in the past day or two.
I see that you have an aluminum radiator converted to multi-pass. Not a store-bought one.
What is the brand of the radiator, and what style? By style I mean, is it standard orientation or with the reversed inlets outlets for later model serpentine set ups?
And who did the converting?

Sorry if you have already covered all that. Don’t remember the details if it was.

 

[Ol'Blue]

Sounds like a good place to start!
What kind of original mileage?
Did they ever supercharge the 5.8 in the Lightning? Or was that just for the overhead cam engines?

I believe the builder said around 70k but I bought if over a year ago and I'm sure he was exaggerating. No supercharger in mid 90s that I know of, but I wish!

Motor only has low 8.8:1 compression, 240 hp at 4,200 rpm and 340 lb-ft of torque at 3,200 rpm stock. With the bigger cam, long tube headers and intake I hope Im getting more.

 

[Ol'Blue]

Just reread part of your first post and wanted to touch on something that was brought up in the past day or two.
I see that you have an aluminum radiator converted to multi-pass. Not a store-bought one.
What is the brand of the radiator, and what style? By style I mean, is it standard orientation or with the reversed inlets outlets for later model serpentine set ups?
And who did the converting?

Sorry if you have already covered all that. Don’t remember the details if it was.

I dont recall the brand for sure, but I think the seller on here said it was Griffin but I could be wrong.

Standard orientation.

Mattsons custom radiators did the three pass, electric booster fan and advised me on what to do about 6-7 years ago. They are well known in Socal.

I did speak to them yesterday and went over my set up. They said changing the tstat to 190 or electric fan sender to 200 isnt going to help.

Said maybe working the shroud a little more could help but with the bigger motor, long tube headers focusing in getting the under-hood temps down could help.

https://the-fan-man.com/

 

[gr8scott]

I will also go to a 190 or 195* thermostat as suggested by several.

I have a 302 bored 40 over and had the same cooling issues while stubbornly running a 180° thermostat.

Switching to a 195° stat cured my runaway temp Issues. With the 195 temps stay way more consistent.

I run long tube headers as well.

I also run two fluid coolers mounted to the front of my radiator. One is for the transmission running water to air.
The other is for my steering/hydro brakes. Neither has any affect on my engine temps or airflow.

And, as per the discussion above, when I bought my bronco it didn't have inner fenders. It still doesn't

I know, 351/302 = apples/oranges. But cooling principles remain the same.

https://www.summitracing.com/parts/bra-330-195

 

[ba123]

Yup, totally. These engines weren’t designed to run cool t stats and don’t listen to anyone that says otherwise, imo. Seen so many cases of running too cool of one being the problem.

 

[Ol'Blue]

Alright, you guys convinced me. I have to pull the radiator and drain the system to trim the shroud anyways so I can swap the stat too.

Will report back, but it will be a while. Carb leak blah blah blah.