[.183953]

Ah! There you go, now you might be on to something.

You are actually under driving the water pump as the crank pulley is smaller than the water pump pulley, so I can see how at idle it just isn't moving enough water and/or turning the fan fast enough.

In my factory setup, the crank pulley diameter is about 7.75" and the water pump pulley is about 6.25".

THIS.
When I first got into cars I was trying to get the "easy" horsepower. Did one of those "performance" pulley swaps and it caused my car to overheat in traffic just like you describe! I went to a stock 6 rib system and cleared all my heating issues up. I thought it was my fan and shroud so I fixed those initially... then went back to factory and poof fixed.

 

[-SS454-]

Very first post you said 240F. Now 215F. Please explain?

Driving (basically idling) for a HOUR in traffic (behind all the other cars emitting exhaust, and blocking air flow) is extremely hard on the cooling system. There is )in my opinion) a HUGE difference between getting 215F and 240F.

I would accept 215F (during the infrequent occurrence), not 240F.

Wanna spin the fan faster in extreme load conditions for free? Push in the clutch and raise the rpm with your right foot.

Info:

https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf

I don't think I can be any more helpful. Sorry.

Pete

The first time I pulled over and shut the car off when it got to 215... it was still climbing. I also drove at those slow speeds with the hood open a few inches. I am sure it would have kept climbing upwards of 240 if I didn't keep shutting it off.

 

[-SS454-]

Hmmm... $250-300 for clutch fan + new crank pulley. Maybe some minimal power gains.

$500 or so for Spal 11" fans and gain upwards of 30 hp.

 

[Hotwire]

Hmmm... $250-300 for clutch fan + new crank pulley. Maybe some minimal power gains.

$500 or so for Spal 11" fans and gain upwards of 30 hp.

$100 for 1996-2002 f-body e-fans from junkyard/craigslist/kijiji
$50 for relays and wiring..

These fans pull so hard they'll suck trash out of your radiator first time you wire them up.

 

[.183953]

Hmmm... $250-300 for clutch fan + new crank pulley. Maybe some minimal power gains.

$500 or so for Spal 11" fans and gain upwards of 30 hp.

You can also use SPAL fans for anything you might do in the future. If you go LS or something like that.

 

[-SS454-]

$100 for 1996-2002 f-body e-fans from junkyard/craigslist/kijiji
$50 for relays and wiring..

These fans pull so hard they'll suck trash out of your radiator first time you wire them up.

I like the idea of junkyard fans, but I want to be sure not to lose the cooling I get at speed. An electric fan with rubber flaps seems ideal to me.

How well does those fans cool for you 40-60 mph?

 

[-SS454-]

You can also use SPAL fans for anything you might do in the future. If you go LS or something like that.

True, but I think a 68-72 Core is a bit wider than the Spal 11" fan sizing, and I may have to get Spal 12" fans if/when I eventually get the correct radiator.

 

[.183953]

True, but I think a 68-72 Core is a bit wider than the Spal 11" fan sizing, and I may have to get Spal 12" fans if/when I eventually get the correct radiator.

It doesn't have to cover the entire core--just most of it. Dewitts sells a system with the 11 inch fans that doesn't cover the entire core and it cools fine, I just bought my setup used and got the 12 inch fans in the mix.

 

[lucifershammer]

Ah, but, I think you may need the crank pulley regardless in either case.

You may not be pushing enough coolant through the system at idle, which an electric fan won't fix - you need the pulley to fix that.

Easy to just start with a crank pulley and see if that helps even with your current fan - the crank pulley might be the root of all your evil. >

Hmmm... $250-300 for clutch fan + new crank pulley. Maybe some minimal power gains.

$500 or so for Spal 11" fans and gain upwards of 30 hp.

 

[Kirk's67SS]

True, but I think a 68-72 Core is a bit wider than the Spal 11" fan sizing, and I may have to get Spal 12" fans if/when I eventually get the correct radiator.

Chris correct as the SPAL Dual 11" Efan/Shroud works great on my 67's Small 23.5" Wide X 16" Hi DF Core Rad

How Wide x High is your Current Rad Core ?

How Wide x High of a Rad Core can you go when you buy a New Rad ??

There are many different choices out there of good Efans/Shrouds that could work for you
PM me your Email and I can send you a MS Doc I have done listing the Various sizes & Makers/Sellers

It doesn't have to cover the entire core--just most of it. Dewitts sells a system with the 11 inch fans that doesn't cover the entire core and it cools fine, I just bought my setup used and got the 12 inch fans in the mix.

I disagree and so do other TCers I am sure
why would you buy something that will only cover/do 1/2 the job !?

Ah, but, I think you may need the crank pulley regardless in either case.
You may not be pushing enough coolant through the system at idle, which an electric fan won't fix - you need the pulley to fix that.

Easy to just start with a crank pulley and see if that helps even with your current fan - the crank pulley might be the root of all your evil. >

A agree with this and is something you should try First with your Current Fan/Shroud System

 

[Hotwire]

I like the idea of junkyard fans, but I want to be sure not to lose the cooling I get at speed. An electric fan with rubber flaps seems ideal to me.

How well does those fans cool for you 40-60 mph?

No issue, have them hooked up to the factory ecm. Stock 195°F thermostat, stock fan tune, fan 1 (fans in series) comes in at 198°F, fan 2 (fans in parallel) comes in at 208°F. Looked through a couple logs, highest I saw was 209 after I'd pulled over and turned the car off to take a phone call, it'd heat soaked while off. Temps came back down after the fans kicked back on. Log says it was a 91 degree day, been very hot and humid here lately.

I thought the factory ecm would cut the fans off going down the road but looking over my logs that doesn't seem to be the case, but haven't had any cooling issues to date. Been 16,000 miles with this setup, cruised, autocross, taken 3 6hr+ road trips averaging 70-80 mph for long stretches, drove in a parade, and have been through countless drive thru lines.

Have no idea what radiator, looks like a cheap parts store replacement, and if it goes with the previous owner it was probably the cheapest he could find..

I would try the stock crank pulley mentioned above, that's solid advice.

 

[japete92]

Ah, but, I think you may need the crank pulley regardless in either case.

You may not be pushing enough coolant through the system at idle, which an electric fan won't fix - you need the pulley to fix that.

Easy to just start with a crank pulley and see if that helps even with your current fan - the crank pulley might be the root of all your evil. >

Easy and free to check.

If I use the data from previous posts:

Current crank pulley = 5.5"; current pump pulley = 6.0". 800 crank rpm = 736 pump rpm

OEM crank pulley = 7.25"; OEM pump pulley = 6.25". 800 crank rpm = 992 pump rpm

Difference is approx 250 pump rpm at idle (800 rpm assumed).

Idle the car at + 250rpm (from what is is now) will duplicate the OEM pump rpm. Use your right foot, or idle setting (if you can get that much).

Let the car sit at idle, heat up, and see what you get.


Questions you may wish to answer:

When neither the clutched fan (at high performance rpm), nor the electric fan(s), are rotating using engine torque (a la racing), is there any 'useful' HP difference? Said another way. When the engine requires fan 'cooling', does it matter (to you) what HP 'advantage' one system has over the other?

Can current alternator/electrical system handle the added 'load' (amp demand) of the electric fan(s)? Perhaps some added costs for the conversion.

No need to proved answers to me. Just thoughts for your consideration.

Pete

 

[-SS454-]

I will check how big my current core is a bit later.

I will also test later by idling at 1100 rpm.

As for my current elec system, I have built ahead for future elec fans. 150 amp alternator and 4 gauge wiring. With a couple relays for the fans, I should be fine. It's an excellent point to bring up.

 

[lucifershammer]

Basically, what you are showing is that the pump is currently under driven by 25% compared to stock at all RPM levels.

It's a good test - not perfect (because you are adding more heat by idling higher) but close enough to see if there is an effect. :thumbsup:

Easy and free to check.

If I use the data from previous posts:

Current crank pulley = 5.5"; current pump pulley = 6.0". 800 crank rpm = 736 pump rpm

OEM crank pulley = 7.25"; OEM pump pulley = 6.25". 800 crank rpm = 992 pump rpm

Difference is approx 250 pump rpm at idle (800 rpm assumed).

Idle the car at + 250rpm (from what is is now) will duplicate the OEM pump rpm. Use your right foot, or idle setting (if you can get that much).

Let the car sit at idle, heat up, and see what you get.


Questions you may wish to answer:

When neither the clutched fan (at high performance rpm), nor the electric fan(s), are rotating using engine torque (a la racing), is there any 'useful' HP difference? Said another way. When the engine requires fan 'cooling', does it matter (to you) what HP 'advantage' one system has over the other?

Can current alternator/electrical system handle the added 'load' (amp demand) of the electric fan(s)? Perhaps some added costs for the conversion.

No need to proved answers to me. Just thoughts for your consideration.

Pete

 

[.183953]

Chris correct as the SPAL Dual 11" Efan/Shroud works great on my 67's Small 23.5" Wide X 16" Hi DF Core Rad

How Wide x High is your Current Rad Core ?

How Wide x High of a Rad Core can you go when you buy a New Rad ??

There are many different choices out there of good Efans/Shrouds that could work for you
PM me your Email and I can send you a MS Doc I have done listing the Various sizes & Makers/Sellers



I disagree and so do other TCers I am sure
why would you buy something that will only cover/do 1/2 the job !?



A agree with this and is something you should try First with your Current Fan/Shroud System

It wouldn't cover one inch on each side(at least for a camaro radiator)
I will say, you're right it is BEST to get it to cover the whole thing BUT may be adequate to just cover 95%.

I also agree, you need a different crank pulley either way you go.
I like electric fans because it gives the most options in the future.

 

[Chris27]

Water pump at idle only puts out somewhere around 10-17 GPM. RPM greatly affects the pump flow. That 250 RPM difference could be significant, depending where it falls on the pump curve. Easy to try increasing the idle so that the water pump RPM is "stock".
I went through all this when I put underdrive pulleys on my car. I'm running a 90's serpentine drive from a truck. With my higher idle than what a 90's truck would have, my idle water pump RPM ended up being the same with underdrive pulleys. I did this to fix alternator overspeeding issues at high RPM, but the low speed cooling was a concern that ended up being fine in my case. Zero difference in E.T. with stock pulleys vs underdrive on my car.
A good water pump can make a huge difference too. Before I went to the serpentine drive setup, I had a cobbled together V-belt arrangement. I changed to an edelbrock pump and dropped 20 degrees in temps at idle. The car used to run cool at speed and hot in traffic, similar to what you're experiencing.

 

[v8440]

Like someone above mentioned, idling it up isn't QUITE as helpful as putting the properly sized pulley combo on it, because the engine makes more heat at an elevated idle than at normal idle, which will offset at least some of the increased cooling that might happen by spinning the water pump faster. If the increased idle speed test helps, then definitely get the right pulley-it'll make even more difference when the engine isn't having to make more heat to spin the pump at the normal speed.

 

[-SS454-]

Measured the current radiator. The core is 26.25 x 18. So I could fit a dual 11 inch or even dual 12 inch Spal E-fan.

I tested the water pump speed. I couldn't hold the RPM's exactly where i wanted, but raising the RPM's did for sure help, but did not cure the problem. As mentioned higher RPM will build more engine heat, but i still kept climbing. I started the high idle test at 210F, and stopped at 224F. I did notice when I dropped down to my normal 850 rpm idle, the temps climbed much quicker.

I think the March 7121 7" pulley would be the way to go, which of course is out of stock through Summit. Do I need a pulley puller to swap it?

 

[lucifershammer]

No puller needed. Take off the belts, remove the 3 bolts that go from the pulley into the balancer and it should come right off. Put new pulley on, put new bolts in, put belts back on.

(BTW - I just checked Summit based on your part number - it says they have 7 left in stock, order soon! )

Measured the current radiator. The core is 26.25 x 18. So I could fit a dual 11 inch or even dual 12 inch Spal E-fan.

I tested the water pump speed. I couldn't hold the RPM's exactly where i wanted, but raising the RPM's did for sure help, but did not cure the problem. As mentioned higher RPM will build more engine heat, but i still kept climbing. I started the high idle test at 210F, and stopped at 224F. I did notice when I dropped down to my normal 850 rpm idle, the temps climbed much quicker.

I think the March 7121 7" pulley would be the way to go, which of course is out of stock through Summit. Do I need a pulley puller to swap it?

 

[Hotwire]

Measured the 00 Camaro fans on my 64, the shroud is 26" x 18". Only modification I had to do was cut a half moon out of the driver's top to clear the upper rad hose, then split vacuum hose and ran it around the shroud's lip to cushion it against the rad. The "ears" on the shroud line up with bolt holes that were in this radiator as you can see in the pic above, was almost too good to be true.

You will have to devise some way to kick the fans on at temp whether manually or thermostatically. If you're decent with following a schematic I can share the design I use when wiring these fans up. Puts them in series on low so both fans are running half speed with 6 volts, can't hear them running, then when 2nd trigger engages it puts the fan in parallel so they both get 12 volts.