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The fan clutch when hot should be close to fully engaged. I suggested the heavy duty Hayden 2747 clutch because it engages at a higher percentage of engine rpm for better airflow.
 

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Discussion Starter #22
Upon further inspection, the ends of the blades look like they have been ground down...why would that be?!?!?! wrong fan? wrong shroud?

Hmmm, the fan and shroud look to be stock due to the correct mounting holes and whatnot.


Again, this is my first Chevelle, so if something looks out of place, please tell me! It won't hurt my feelings!


What kind of fan clutch is that...stock??
 

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You mentioned sensor above the left exhaust manifold—this is the head temp; this will also register 20-40 degrees hotter. 220 at the head is about right
 

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Discussion Starter #25
You mentioned sensor above the left exhaust manifold—this is the head temp; this will also register 20-40 degrees hotter. 220 at the head is about right

Interesting...so my dash cluster is all stock. Did they come that way in 1970, with the water temp at the head? If so, then I'm actually right where I should be then, right? Like I said, when cruising, it stays pegged at 210-215. Sitting in traffic, that's where it creeps up to around 230-240.


Again...my first Chevelle, but this looks like a water temp sensor to me, and the right location. When people talk about water temps in the 180-190 range, where do they have there sensors plumbed into? Manifold?



Like I mentioned in the first post, I find it hard to believe that I'm "overheating" due to the lack of any normal symptoms. But then again, I'm no Chevelle cooling system expert.
 

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That’s the right spot for the sensor and where you get the highest reading. The boiling point of 50/50 EG water is 265F at 15 psig. As long as you are reasonably under this (220F), not boiling off coolant, and your idle mixture and timing suit the temperature you should be OK.

It is certainly preferable to operate cooler (190F full time would be great) but it may just not be practical. A 220F head reading might read 200F or so at the intake? This would be considered acceptable for me, but I know others here have a lot of differing opinions.

I have a fresh 496 in a 67 that I haven’t had on the street yet, but at idle after 10 minutes or so it sits around 210. I am reading from the same sensor as yours.
 

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You need to confirm the sender is working correctly and that is the correct application. I believe that the correct original sender used a threaded stud for the electrical connection when optioned with a factory gauge and a pin with a push on with a warning light.
 

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Yep, we have been at Moody for 3 years and love it! Trying to stay another 3 actually!! But thanks for the advice. I'm heading to Autozone in a few minutes to pick up a Tstat and one of those solid state VR715 regulators (pulsing lights), and I'm torn between the 180 and 160. I may go with the 160 since it seems to want to hit 240-250 easily and it's always hot down here.
I'd read up about cooling systems if I were you. A 160 thermostat isn't going to cure an overheating condition. GM engineers designed a system to run at 195* minimum when fully warmed-up. People who would tell me stuff like "run a cooler thermostat" would have zero credibility in my book, cuz I'd wonder how they got smarter and more experienced than the GM automotive engineers. Just my $0.02
 

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An engine with 70,000 miles on it is different then a brand new engine with 100 miles on it. Combustion chambers get smaller so compression goes up, cooling system passages also get caked up, so things need to be changed with use..

Those engineers are hand cuffed by a one size must fit all rule when they design these cars. The owner isn't bound by those restraints and is allowed to tune for best performance based on climate and terrain. I think you are handicapping your car by using stock specs, especially front end tire alignment, these cars were spec'd with negative caster!! Surely you don't use negative caster and positive camber but these cars were spec'd that way..
 

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I think I'd set the timing correctly and make sure the fuel mix is right before I spend money on fans and clutches . Also the IR temp gun is on sale at Harbor Freight right now for $16.99. Im going to get one myself . Sweeeet car BTW
 

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Discussion Starter #33
I think I'd set the timing correctly and make sure the fuel mix is right before I spend money on fans and clutches . Also the IR temp gun is on sale at Harbor Freight right now for $16.99. Im going to get one myself . Sweeeet car BTW

My buddy is bringing his over tomorrow. And thanks for the compliment man!! I've always liked the 70 Chevelle, so I figured I get one instead of a Mustang this time!
 
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Flushed the radiator, added new coolant. Pulled thermostat and it was a 160. So, I thought maybe it had gone bad, so I picked up another 160 tstat at Autozone for $12. Put it in and buttoned everything up. Test drive, still was cruising at 210, and in traffic bumped up to 230. The sensor is in the stock location, just above the left side exhaust manifold. The shroud looks to be correct and hugs the fan tightly. The radiator looks to be in good condition both on exterior and the interior (from what I can see with a flashlight). The overflow tube is clear. I also ran the heater to clean out the heater core, and it was producing heat like it should and the lines were warm. The 7 bladed fan has some resistance when engine is cold, and slightly more resistance when engine is hot.

But, I'm still thinking the gauge or sender is suspect... This car was recently restored/rebuilt and it runs like a dream, but according to the gauge, it runs at 240+ if sitting in traffic. I've stopped several times, popped the hood, no burning smell, no steam, no boiling, nothing coming out of the overflow, fan turns fine, nothing coming from tstat housing, nothing coming from any lines, nothing leaking on the ground. I'm not a Chevelle expert, but I'm scratching my head at this point.
You're just shootin' in the dark until you get a reliable baseline configuration. If a 160* thermostat was installed, it ain't stock. Somebody's been tinkering.
 

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Something also to consider,,,,,,,,,,, Your fan blade. It is not a 3947772 blade. Not sure what fan blade it is. A 1970 -396/454 with VO-1 cooling or some call it H.D. The fan blade is a 3947772 and it is STAMPED with these numbers.
This way you have NO doubt what fan blade is on your car.
Why this fan blade and why are the numbers stamped on it???????
This blade was designed for the B.B. cars with A/C and or H.D. cooling.
Also this 394772 blade has the correct pitch to draw air through the heat exchanger and " Also very important",,, It will remove the SUPER HEATED AIR from the engine bay. ( everyone blames vapor lock on EVERYTHING else. Most of time your engine bay is NOT like it left the factory. Parts are MISSING,,,,,The Super Heated air is staying under the hood and " NOT " being EXPELLED!!!)
My one owner 70 SS 454-M/22 car has the VO-1 with A/C, The 3947772 blade was part of the FACTORY Pkg. The org. clutch was made by EATON, You will hit the Lottery before you find an Eaton Clutch!
I am a Geeser, I would do Four items.
1- Heat Gun
2- A new Mech. Temp. Gauge. ( the first time I did this, I duct taped a mech. gauge to the windshield and go for a ride) Write down speeds & Temps.
3- Get a correct fan blade and make SURE your clutch is working.
4- correct any out of order items. Thermostats, I have a 180 & a 160 in Two different cars both with Q-Jets, Other than warm/up time=" NO DIFFERENCE " Thats your call.
...........................................................................................................
If you revert back to the factory Org. cooling system set up, Your system will function properly. Over the years items get changed, Then you have issues. Take it " One step at a time ".
Good luck
Bob
Trivia:
The- O.E.M. fan blade AKA 3947772 has curved tips WHY? The REAL O.E.M. 772 blades with curved tips match the radius of the plastic 1970 fan shroud. Do the Repo. blades have curved tips? The Repo I bought Did not and it MACHINED a hole in the Factory fan shroud. That blade did not make it to "door stop" statis,,, It went to the F^!%$EN scrap!
 
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Discussion Starter #36
Something also to consider,,,,,,,,,,, Your fan blade. It is not a 3947772 blade. Not sure what fan blade it is. A 1970 -396/454 with VO-1 cooling or some call it H.D. The fan blade is a 3947772 and it is STAMPED with these numbers.
This way you have NO doubt what fan blade is on your car.
Why this fan blade and why are the numbers stamped on it???????
This blade was designed for the B.B. cars with A/C and or H.D. cooling.
Also this 394772 blade has the correct pitch to draw air through the heat exchanger and " Also very important",,, It will remove the SUPER HEATED AIR from the engine bay. ( everyone blames vapor lock on EVERYTHING else. Most of time your engine bay is NOT like it left the factory. Parts are MISSING,,,,,The Super Heated air is staying under the hood and " NOT " being EXPELLED!!!)
My one owner 70 SS 454-M/22 car has the VO-1 with A/C, The 3947772 blade was part of the FACTORY Pkg. The org. clutch was made by EATON, You will hit the Lottery before you find an Eaton Clutch!
I am a Geeser, I would do Four items.
1- Heat Gun
2- A new Mech. Temp. Gauge. ( the first time I did this, I duct taped a mech. gauge to the windshield and go for a ride) Write down speeds & Temps.
3- Get a correct fan blade and make SURE your clutch is working.
4- correct any out of order items. Thermostats, I have a 180 & a 160 in Two different cars both with Q-Jets, Other than warm/up time=" NO DIFFERENCE " Thats your call.
...........................................................................................................
If you revert back to the factory Org. cooling system set up, Your system will function properly. Over the years items get changed, Then you have issues. Take it " One step at a time ".
Good luck
Bob
Trivia:
The- O.E.M. fan blade AKA 3947772 has curved tips WHY? The REAL O.E.M. 772 blades with curved tips match the radius of the plastic 1970 fan shroud. Do the Repo. blades have curved tips? The Repo I bought Did not and it MACHINED a hole in the Factory fan shroud. That blade did not make it to "door stop" statis,,, It went to the F^!%$EN scrap!

Bob, thanks for the input!! Definitely gonna tackle this one by first figuring out what temp it ACTUALLY is. The gauge is stock, but the PO said it was rebuilt, so it could have the wrong resistor...? I don't know honestly. But, we'll see what the gun says tomorrow!
 

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The curved tips on the 772 fan blades were also designed to minimize fan noise.
 

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I agree Randy. Chevrolet designed it to do a job. So far for me , The last fifty years that I have owned and driven my LS-5/M-22 El Camino. No issues so far, So I do believe Chevrolet got this right...:thumbsup:
P.S.:
My one owner SS 454 and my FAKE SS 454, AKA(468), both have O.E.M. cooling systems. My 468 driver has over 41.000 Highway miles on, So far So good. Yes I do have an Electric fan, I blows the KOLD AIR through the Evaporator to the inside of my wagon...:laugh:
Bob
 
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I agree Randy. Chevrolet designed it to do a job. So far for me , The last fifty years that I have owned and driven my LS-5/M-22 El Camino. No issues so far, So I do believe Chevrolet got this right...:thumbsup:
P.S.:
My one owner SS 454 and my FAKE SS 454, AKA(468), both have O.E.M. cooling systems. My 468 driver has over 41.000 Highway miles on, So far So good. Yes I do have an Electric fan, I blows the KOLD AIR through the Evaporator to the inside of my wagon...:laugh:
Bob
Love everything about your 70 wagon. That’s my next purchase!
 

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I've had cooling issues with my BB in the past and now I run a constant 170 +/- driving, 190 while idling.

This is what I`'ve learned on Team Chevelle from mechanically superior minds than my own.

First, a 180 t-stat should work just fine. The reason why; a cooling system has to work in cycles. Once the t-stat opens, it cycles the coolant into the radiator where the cooling takes place. T-stat will close and the radiator does its job, (as long as it's clean and the fins aren't crushed)

Running a 160 might not get you the proper cycling you need due to the t-stat remaing open at higher temps. The t-stat needs to close to optimize the cycling. This is why that old myth of not using a t-stat at all will keep the coolant constantly moving through the system is better. Totally wrong.
Your 195 may not have been working properly.

Try the 180 and get your timing right.
I also run full manifold vacuum to my vac adv. FWIW.

Only trying to pass on what I've learned and what worked for me.

Nice 70 :thumbsup:
 
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