Mild 340 build runs hot
- Thread starter John Trickler
- Start date
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Same radiator I had that didn't flow air. Put a light behind it and see if you can see through it clearly. My tubes were ovaled from over pressured some where along the line. Could have been when pressure tested. I thought mine was a unique issue but have since heard of others with the same problem same rad.
Did you get the high flow water pump pulley when you got your kit? I had to specifically order that high flow pulley when I got my setup. They default to the large diameter pulley which will not flow enough for street use.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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If it runs hot below ~30 mph, and as you say, "the rad is doing it's job" (with the spalls); then the gauge must be wrong.
If it runs hot above ~30mph, and as you say, "the rad is doing it's job"(with the spalls); then yur not getting ram air thru it.
If it runs hot at idle, and as you say, "the rad is doing it's job"(with the spalls); then obviously it's not.
>The common thread here is "the rad is doing it's job", SO,
what's your definition of, "the rad is doing it's job?"
My engine build is or has been,
much like yours except an 11/1 360-4spd. In the beginning it did run hot. It would lock up every time I shut it off, and sometimes, I'd have to wait 20 minutes with the hood open, before it would crank again. and, it seemed to be a lil down on power, and hard on gas.
The engine had been set up with hypereutectics at .0035, and cast rings, at a ring factor of .0065 per KB's instructions.
Well, after spending the entire summer chasing it down, spending a ton of money, I was right where you now are. So,
that first winter, I pulled the engine out and down. I sent the block out to be honed a lil looser, bought some Moly file-fit rings and a tool.
I opened the top rings to .0085 factor (.034),
and the Seconds to .0075 factor (.030),
up from all at .0065 factor(.026)..
That cured it.
Around 2004, I installed a NEW HD FORD Thermostatic Clutch, listed for a Pick-up,
>Here's my definition of, "the rad is doing it's job";
My cooling system will NOT go above 207*F;
no matter the outside temp, and
no matter the speed she's driving, and
no matter the Idle-timing,
and, my rad is a factory 26" A/C unit from 1973 Dart 318 A/T, which, in 1999, already had patches on patches, and she's set into a stock slanty core-support with a 19"opening.
Now, you may think my ring gaps are excessive.
To that I respond, well; Leak-Down was very low on my gauge; Or,
You might think that A/C fan must really suck power;
To which I respond; come'on, it's on a clutch!
FOUR years later, the car went 93mph in the Eighth;
at 3457 pounds/900ft elevation/on a Hot July day. The Wallace calculator says this takes 433hp; so
Ask me if I care how much power that fan sucks ....
Here is a list of mods I did prior to the ring-gaps change;
>Pure water, with a Hi-Flow Pump and stat,
>Molded hoses, with a restricted bypass,
>Rad sealed to core support and front of hood, rear of hood elevated and seal removed,
>A really Big, hi attack angle, 7-blade, all steel fan, with up-turned tips, in a matching shroud,
>Fresh cold air from outside the Engine-compartment fed directly to a boxed carb,
>I even ventilated my hood.
> chassis loosened to roll easy.
> NONE OF THE ABOVE made much of an improvement.
Just so you know;
1) since then, my pump and alternator are now underdriven, for two reasons;
a) I run a manual trans, so, the rpm is always up, and
b) since I like to rev to 7200, just cuz it sounds so wild; I like the old belt to stay on.
2) I now run a 195stat, up from 160,
3) when I parade, I retard the timing to 5*, at which, the 360 pulls itself along at 4mph= 550 rpm, smooth as silk, and, to date, it has always run a solid 207*F. It has to, cuz that big fan really works.
4) I now run an overdrive and 65=2240. I run this at about 50* advance, cuz that's what she wants at 207*F, while running as lean as I dare.
5) BEFORE I had overdrive, 65=2870, and she liked 56*. There were times, she was liking over 60*.
To get these numbers, I installed a dash-mounted, dial-back, Timing Module with a range of 15 degrees. The trick is to remember to dial it back, when I come off the hiway....... lol.
Your results may vary.
PS,
I'm not telling what you should do.
I'm informing you of what I already did, and what worked.
Happy HotRodding
Last edited:
gzig5
Well-Known Member
This ^^^
Forced air only going through 50-60% of the radiator surface area. There is a reason every factory vehicle for about the last forty years come with a shroud on the fan/radiator. Efficiency.
I agree with electrical fans and no shroud being issue. Original shroud and rad here, no overheat issue.
John Trickler
Well-Known Member
Sorry, but I disagree. My limited experience with my B-Body, shroud was needed with my mechanical fan, but with dual electric, my shroud was a hinderance. I know others will disagree. Also, going down the highway I run the same temp. Fans shouldn't even be on at highway speeds, but they do.
John Trickler
Well-Known Member
I will contact them and ask about that option. Thanks
You verified the elec are pulling, not pushing? Unless you have tried 7blade fan and oem shroud on THIS engine, I would try.
John Trickler
Well-Known Member
I would have preferred a 7-blade with a clutch like Ma Mopar did, but I don't have the room.
I put a 340 in place of factory 273. Original 7 blade fan, rad and shroud all used on 340 and no issues.
You've come here asking for help. We need more than "way big" and "nice temperature drop" as descriptions. You may as well have posted "help, my car's running hot, it's blue" Give us the pertinent information and we have an actual chance of helping. Otherwise every suggestion here is a shot in the dark. I completely agree with @toolmanmike though. Usually the problem is with the aftermarket serpentine setups OR the crappy electric fans.
John Trickler
Well-Known Member
I understand that I did not have detailed notes. I had a video with it running and the temp gun but I goofed and deleted it. The rad was in a 73 Dart with a blown Hemi in it without issues. Coolant drop from top to bottom with the car running was about 40 degrees. I know this won't satisfy some of you, but I have plans to check over some suggested items. Then fire up the car and maybe get a better video of temps.
Cars have pretty much always had radiator shrouding. It definitely predates the 60s.
I had a temp gun that was way high. Verified with known good one from work.
Make sure it's not a cheapie.
Make sure it's not a cheapie.
middleagecrisis
Well-Known Member
Two no cost suggestions for you that I didn't see listed in both pages. I'd do these before you start throwing money at the problem:
1. Take the radiator cap off (Engine Cold) start up the car and watch coolant flow through the radiator, once it comes up to temp and the thermostat opens. You should be able to tell if the coolant is flowing through at a sufficient rate, indicating if pulley size is incorrect.
2. Verify heat gun and temperature gauge in car match each other. "Shoot" the block with the heat gun in the front away from the headers and also wherever your temp sending gauge is located. Use these readings to verify if your gauge is reading correctly.
To answer your original question, I'm not sure if there is a top and bottom to the head gaskets, I believe there is. I always make sure all holes in the block line up with the head gaskets before I assemble. I'd also do as recommended in this thread and shine a light from the inside of the radiator and look for obstructions in the fins. Good luck and please let me know if you verified steps 1 and 2.
1. Take the radiator cap off (Engine Cold) start up the car and watch coolant flow through the radiator, once it comes up to temp and the thermostat opens. You should be able to tell if the coolant is flowing through at a sufficient rate, indicating if pulley size is incorrect.
2. Verify heat gun and temperature gauge in car match each other. "Shoot" the block with the heat gun in the front away from the headers and also wherever your temp sending gauge is located. Use these readings to verify if your gauge is reading correctly.
To answer your original question, I'm not sure if there is a top and bottom to the head gaskets, I believe there is. I always make sure all holes in the block line up with the head gaskets before I assemble. I'd also do as recommended in this thread and shine a light from the inside of the radiator and look for obstructions in the fins. Good luck and please let me know if you verified steps 1 and 2.
Inertia
Well-Known Member
The locating pins for the head-gaskets assure they can only go on one correct way .
40 degrees is not much. Satisfy? Look pal, you're askin for help. We're trying to give help. If you don't think adding details is important, then you're getting ready to alienate a LOT of knowledgeable people who can help solve your issue. Also, a roots blown engine is not a good comparison, as yes, compressed air causes some heat, BUT it also has a tremendous cooling effect too. This is one reason roots blown engines are so efficient.
WTF are all these cats coming from askin for help and then get bent out of shape when we ask for more details actually TRYING to help? Count me out of this one, too. I have better things to do with my time than pull answers like I'm pulling teeth.
TT5.9mag
Two atmospheres are better than one
WTH are you talking about Rusty. Lots of NOPE in those two sentences.
Not from my experience.....but it's really all for naught anyway. lol
TT5.9mag
Two atmospheres are better than one
That I agree with. Let’s move on.
If the temp on the rad is 40* different from top to bottom the rad is working right for aluminum , about 18* for copper so what you got?
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