Anyone using an electric water pump?

[Detroit Bill]

Running to cool is not good. Are your temps over 200 infrequent and brief?

[scottj]

Negative on lower flow rates (water or air).

It's a closed system. The longer coolant is in the radiator, the longer it's in the block gaining heat.

There is a reason companies like Stewart Components make electric booster pumps that install in the return hose. By increasing pressure behind the mechanical pump they can get higher flow rate without cavitation of the mechanical impeller.

Rate of heat transfer (Q) equals the mass flow rate (M) times a Constant (the specific heat of water) times the Delta T (fluid temp out minus fluid temp in):


Q = M x C x Delta T

The rate of heat transfer is directly proportional to flow rate. If you increase the flow rate, you will then increase the rate of heat transfer.

[cycleguy55]

Originally Posted by Jaydee

I was told by my radiator guy that if the flow is to fast , then the coolant doesn't get a change to cool down, because it goes through the radiator to fast. So the thermostat serves as a restricter as well as regulating the temp.
JD

Your radiator guy is giving you bad advice, probably based upon advice he got from someone who didn't know better. As scottj pointed out in post #22: "The longer coolant is in the radiator, the longer it's in the block gaining heat." That's almost a direct quote from what Stewart Components includes in their cooling Tech Tip #3. Stewart Components

More content from the same Tech Tip:

• "We strongly recommend NEVER using a restrictor; they decrease coolant flow and ultimately inhibit cooling."
• "Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures."
• "Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would over come the
  radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations
  were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool."

[jetblue69]

Originally Posted by Sledge

On warm and hot days (85 deg F and above) I see water temps of 195 to 210 deg F, using a slightly larger (M3) than stock radiator and a belt driven Edelbrock water pump, even with my BMF Spal electric fan on. So, I was wondering if an electric pump, with a more constant flow, would be helpful. I'm using about 30% anti-freeze, 1 bottle of Water Wetter, and the rest is distilled water. 99.9% driven on the street in sunny SoCal. Lots of stop and go.

Brand, flow rate, etc recommendations appreciated.

Thanks

It ain't broke, don't fix it. 195 - 210 is perfectly fine...especially in those temps.

[jeffnolan]

Air is a poor conductor of heat, only the first layer of air touching the radiator fins has a cooling effect, the surrounding air doesn't get much tansfered to it. Convection by continuously replacing the contacting layer with fresh air increases the heat transfer to the bulk of the air in the vicinity of the radiator by conduction. Slowing down the air flow through the radiator quickly saturates the contacting layer of air to no effect on the surrounding layer, which is why no one recommends it.

Originally Posted by scottj

Yet no one ever recommends slowing down airflow through the radiator to give the air more time to absorb the heat... hmmm, strange.

[scottj]

Originally Posted by jeffnolan

Air is a poor conductor of heat, only the first layer of air touching the radiator fins has a cooling effect, the surrounding air doesn't get much tansfered to it. Convection by continuously replacing the contacting layer with fresh air increases the heat transfer to the bulk of the air in the vicinity of the radiator by conduction. Slowing down the air flow through the radiator quickly saturates the contacting layer of air to no effect on the surrounding layer, which is why no one recommends it.

Yes, I understand. The post you quoted was actually meant to be sarcasm. What most fail to understand is that the same applies to both air and water flow with regard to flow rate.

[GBowman]

Late to the party here...but...I have found a huge benefit in my elec water pump (Meziere) is that when I shut down I can turn the key on and have water pump & fan run for a couple of minutes with the engine turned off in order to mitigate heat soak. This is a huge up side if you do any restaurant hopping and only shut down for an hour or two at a time. I've had heat soak issues in the past and this has cured that problem 100%.

[lippy]

For my setup, a 487 BB, the Edelbrock pump cools it just fine, even on hot days. I have a big radiator and a Spahl fan also. There are benefits to an electric pump, but I don't like the added complexity and sudden failure mode.

[Sledge]

Gary:

Have you had any reliability issues with the Meziere pump? Also, is yours set up just like a mechanical pump, that is, with a thermostat and electric cooling fan?

One of the previous responders talked about a system with an electric pump and a control unit that would vary pump speed and fan speed to maintain temperatures, with no thermostat. Sounded like it would work well, but also a bit more complex and expensive than I was looking for. Still kicking it around though.

Thanks to all responders!

I'm not, in my ignorance, ready to agree with the "if it ain't broke" crowd as temps over 200 or so, even if only temporary, make me kinda nervous with this older carb'd engine. I don't believe it was built to run that hot. Just MHO.

Cheers

[cycleguy55]

Originally Posted by Sledge

I'm not, in my ignorance, ready to agree with the "if it ain't broke" crowd as temps over 200 or so, even if only temporary, make me kinda nervous with this older carb'd engine. I don't believe it was built to run that hot. Just MHO.

Cheers

Do you have an oil temperature gauge? One of the factors in selecting a thermostat is getting one that will allow your oil to reach at least 212°F / 100°C in order to drive out any moisture in your oil. Your oil temperature can't get hot enough unless the coolant temperature is hot enough - the two are related. It depends upon the engine, but oil temperatures are usually hotter than coolant temperatures by 30-40°F - once things are all warmed up.

I have an oil temperature gauge and it takes a lot longer than you might think to get the oil temperature over 212°F / 100°C. Now, my 11 quart road racing pan with 3/4 length sump probably has something to do with that, but the message is clear: just because your coolant is up to temperature doesn't mean your oil is.

[Sledge]

Brian:

Thanks for the info. I've had two different oil temp systems on my car and both of them have indicated that the oil rarely gets above 160 to 180 deg F unless I'm at the track. Meanwhile water temp will be as high as described previously. I've heard from other 351W owners that their oil temps run cooler than what they have experienced with other engines.

You're going to be evaporating water in the oil before you get to 212 deg F, right?

Cheers

[jhv48]

Might have missed it, but do you have a 180 degree thermostat or a 195 degree thermostat?
If not sure, install a 180 and see what happens.

[GBowman]

Sledge

I have the standard set up, no variable speed. Just an electric fan, the upgraded Rad from BDR, Meziere pump & sending unit mounted in the hard line. No issues so far, 3000 miles. I also put a Cool Carb plate under the carb, the ability to cool the engine way down at shut down is big for me because we do a lot of stop and go in the summer at the shore and I used to have a lot of issues with the fuel boiling out of the carb...no more.

Brent Lykins who built my motor said the same thing about coolant/oil temps. He like the oil hot to get moisture out and isn't concerned at all with 200 deg.

[cycleguy55]

Originally Posted by Sledge

I've had two different oil temp systems on my car and both of them have indicated that the oil rarely gets above 160 to 180 deg F unless I'm at the track. Meanwhile water temp will be as high as described previously. I've heard from other 351W owners that their oil temps run cooler than what they have experienced with other engines.

Are you running an oil cooler? I'm assuming you must be for your oil temperatures to remain cooler than your coolant.

Is the cooler thermostatically controlled, or cooling all the time? If the latter and it was my car, I'd be installing a thermostatic setup to allow the oil to get up to temperature. Here's a couple of examples, easily plumbed into oil cooler lines:
High-Flow Engine Oil Cooler Thermostat, 185F FSM-185
Earl's 501: Remote Oil Thermostat Billet Aluminum | JEGS

Originally Posted by Sledge

You're going to be evaporating water in the oil before you get to 212 deg F, right?

Correct, water will evaporate at room temperature, but it will obviously evaporate faster at higher temperatures. My preference would be for 180°F to be at the low end of the range - it would preferably reach 210°F or higher during normal use. I'm running full synthetic, so it can handle temperatures well over 250°F - and I've never been close to that.

[Sledge]

Thanks Brian

I do have a thermostatically-controlled oil cooler that I installed after a track day at Big Willow that brought my oil temp way up (over 250) from its usual 160-180. To be clear, there was no oil cooler before the track day, and the temps were cool even then during anything resembling normal driving.

I have the oil cooler blocked off at the moment.

I use a Canton road racing pan and 8 quarts of fully synthetic, although the pan will hold more.

Someone previously asked what my thermostat was, a 160 or a 180. It is a 180.

Cheers