LocostUSA.com

Hey folks,
I have a question for you. I am experiencing some overheating issues.... again. I know I have a corvette water pump installed (see page 3). I understand, just recently, that some of these corvette pumps are actually supposed to turn in a counter-clockwise direction (i.e., in reverse). Is it possible that I have one of these and that this feature could be causing a slower, ineffective flow? Would a corvette pump designed to run in reverse actually work in a clockwise direction??
Hmmm.....

Bader,

Yes, Corvette water pumps designed for the serpentine system are designed to turn in the opposite direction of the crank. The backside of the belt runs around the water pump pulley in C4 Corvettes with the Gen. 1 SBC. If you're running it the other way, cooling will be compromised. But, I'm not sure how much.

I know people who have run Corvette pumps the normal direction (clockwise) and have had no problems with cooling. I suspect your problems are larger than just the water pump.

Radiators for cooling a SBC are usually quite a bit larger than the one you appear to be running, though I must admit it's hard to tell the size from the pictures. Yours does appear to be at least a dual core, and that would help.

Also, as you surmised already, air has no easy exit from the front of the car after it has passed through the radiator. This means that less air passes through than would otherwise. The pressure differential, front to rear, determines how much air moves through. A really good puller fan assembly could make a difference, but it doesn't look like you have room for it.

Lastly, the plumbing from front to rear has a large number of bends, many of which appear to be approaching 90 degrees. These slow down the flow of coolant, and compromise cooling.

Given the way the car is set up, this is a tricky problem to solve, if the problem is more than just picking the wrong water pump. But, a few thoughts come to mind. An additional electric water pump placed close to the radiator at the front of the car might help, an auxiliary radiator plumbed like a heater core with a big fan in the back of the car (which could also serve as a reservoir) might help, or a more dramatic (think GT40) hood vent could help. Is it possible to get more cooling out of the twin aluminum pipes (tubes?) that travel through the tunnel?

I keep thinking, though, that you have plenty of room for a big radiator and fan in the back of the car. Cooling with twin radiators through side ducting/scoops behind and beside the driver and passenger might actually be simpler, easier to bleed, and cheaper.

Just thoughts anyway...

-Graveyard

_________________
Aedifico ergo sum.

[quote="badermatic]I have a question for you. I am experiencing some overheating issues.... again. I know I have a corvette water pump installed (see page 3). I understand, just recently, that some of these corvette pumps are actually supposed to turn in a counter-clockwise direction (i.e., in reverse). Is it possible that I have one of these and that this feature could be causing a slower, ineffective flow? Would a corvette pump designed to run in reverse actually work in a clockwise direction??[/quote]Yo, Bader! I'm not a Chebby expert, but in 302 Fords running a clockwise pump in the counter-clock direction or vice-versa will not cool sufficiently. I'd make sure you have your pump turning the correct way...

How-some-ever, I think you might have more problems than that. Increasing the airflow and/or a larger or even a second radiator, as has been suggested, might be good ideas for you to consider.

All IMHO, and as you know, "I ain't no enga-neer!"

JDK

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

Graveyard and Gonzo,
Thanks for your replies. I pulled the pulley off the pump and obtained GM's casting number (5016-12) off the face of the pump yesterday. I then sent out a query regarding the rotation to various GM experts and hopefully will get a reply. I don't want to pull off the pump and open the back to take a peek unless I actually have too.

Anyway, I like your ideas about the supplementary rads and remote pumps. I hadn't considered the remote pump concept previously. if I locate a pump near the rad should it be near the inlet or outlet side of the radiator?

A supplementary radiator above the engine might fit. I think the side pod rads would be too small. Am still looking into it.

BTW - My current radiator is a Ford New Holland (Model A-83765). It measures 16.75" x 11.75" and is a 4 core. It was originally made for a skid steer.

Thanks again for your help.

ordinarily, centrifugal-style pumps are designed such that the impeller and volute (that's the path outward on the pump, usually designed with an expanding diameter along its path) are designed to work together, with the impeller spinning in one particular direction to pressurize and force whatever fluid being pumped out the volute, in the direction of the volute's expanding internal diameter. spinning the impeller in the opposite direction, while still pressurizing the fluid within the housing, would be forcing it in the opposite direction of the volute's path. the pumped fluid would still exit the volute due to the pressurization, but its flow would be much less efficient.

here's a grain of salt to take with that.

_________________
The B-3 build log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=13941 unfortunately, all the pictures were lost in the massive server crash

The beginnings of the Jag Special,
https://www.locostusa.com/forums/viewtopic.php?f=36&t=19012
Again, all pictures were lost.

Thanks Robbovius! Grain well taken.

Meziere Enterprises thinks I would be better off with a remote pump low and near the radiator (rather than an electric pump attached to the block). I believe I could use the remote pump in conjunction with the existing mechanical pump.

The two leading supplementary radiator candidates that I am considering are:

A Porsche Cayman center rad could potentially be placed between the frame rails in the back of the vehicle. It measures7 3/4 inches high, 1 3/4 inch thick and 23 inches wide from outlet to outlet. The main body of the radiator without the coolant outlets is 19 inches.

Two Yamaha Raptor 700 ATV radiators (which each measure 16.6” x10.1” x3.2”) could be placed (angled) in side pods in front each rear wheel.

Do you folks see anything wrong with using an ATV radiator for this purpose?

Hi folks,
Its been a while since it posted, but I haven't given up. I added the Porsche Cayman center rad, in series, to the coolant system (see diagram). I'll be hooking up the final connection for the fans tomorrow. Here's a pic of the install. I'll let you know how it goes when I fire up the beast this weekend.

Good luck with that and hope all you heating problems disappear. Looking forward to the results.

_________________
Larry in Seattle

Thanks Larry. Things looked promising tonight. Brought the beast up to temp and it stabilized at 180° for 5 minutes with no major drama. Tomorrow I'll give it road test by driving to a local car show (about 23 mi away). Hopefully I'll have a boring story for you.

If it's an uninteresting trip that will be indeed post worthy. That's what we are hoping for!

_________________
Larry in Seattle

Success! No drama! No overheating! The car handled the trip well. Upon arrival I noticed a couple of very minor drips from some of the connection points, but with aide of a flat bladed screw driver these were quickly resolved. One thing I did notice was that my temperature gages were both off. The one on the forward radiator was reading 265°F and the other off the engine block read from 120°F to 150°F the entire time. Something amiss here but no overheating, no puking of the green stuff. Very happy.

_________________
Larry in Seattle

Well that's good to hear, congrats.
Kristian

_________________
V6 in a book frame build. Now registered.
viewtopic.php?f=35&t=7587
viewtopic.php?f=33&t=18172

So I solved my temperature sensor/ gage issue. After some diagnostics, it was apparent that I simply had a loose connection at the sensor. Solved by a little tightening of the nut where the wire attaches to the sensor. Temperature gage is working well now. And still no over heating issues, even in 90°F ambient temps. Life is good again.

And while you're at it, maybe you should had oughta tighten up the loose nut behind the wheel!

Just kiddin... Glad you got it fixed...

JDK

_________________
JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom