[1967Tempest]

Is there a picture of this, because I was thinking of fabricating one of those .

Dave

[GT182]

Peter, I'd be interested in seeing pictures of the metal plates too. Could we trouble you for some please?

[1967Tempest]

Well, I tried some new set-ups this weekend to see if there was any way to get more air through the radiator. All tests were with 60/40 water to AF ratio with water wetter and a 160* thermostat

1. Installed new lower rad hose for the Griffin Rad Napa PN#NBH-7463 (Thanks Pont406) No real change is cooling ability, but nicer too look at!!.

2. Tried to run just the Electric fan as a puller. Removed the mechanical fan (car did seem to sound quieter with no fan attached to water pump, go figure.) . Fan centered in rad with existing mechanical fan shroud. Temps were are 200-205 cruising at 45mph.

3. Returned to previous set-up, but now the electric fan is centered in the middle of the rad as a pusher (it was slightly off center before) 18" race fan re-installed. Temps are back to 170*-175*.

I was at a cruise night and ran into a fellow Pontiac-er and was admiring his stock GTO with a 455 STOCK.. The clutch fan was 50/50 in/out of the fan shroud and it was PULLING air!!! My fan is currently 100% in the shroud. I have tried the 50/50 before with poor results. However I think that it was a bad tune on my part, so that will be my next try.

I was going to make a plate from the bumper to bottom of radiator, but once the temps shot back DOWN, I figured I would post this before the hassle. Plus I wanted to see some pictures.

Dave

The picture is old. I will take a new one, but you get the idea.

[Bruce68gto]

Nice info from all on engine temps. My 68 runs up about 20-25 degrees on a drive on a warm day. I was told to check my clutch fan and found it to be free wheeling and I could stop it with a rubber hose. So I am waiting for a new clutch fan and hopefully it will help the warm up problem.

[guccieng]

"2. Tried to run just the Electric fan as a puller. Removed the mechanical fan (car did seem to sound quieter with no fan attached to water pump, go figure.) . Fan centered in rad with existing mechanical fan shroud. Temps were are 200-205 cruising at 45mph.


3. Returned to previous set-up, but now the electric fan is centered in the middle of the rad as a pusher (it was slightly off center before) 18" race fan re-installed. Temps are back to 170*-175*."

you did reverse the polarity of the wiring to the fan, right? your fan might not be reversible, too.

[1967Tempest]

Polarity??? WTF??? Kidding.. Of course!! Had to remove the blade and flip it and then swap polarity. It did pull a lot of air. But with the lack of the electric shroud, it didn't pull as much as the mechanical puller and electric pusher.

[Ben M.]

Here's a dumb question... everyone loves to re-do their divider plate and clearance it properly... but who has actually replaced the rock hard 35 year old o-rings in the water pump sleeves? That is one heck of a difference if you've never done it.

[1967Tempest]

When I did the spacer plate mod, and added the new cast water pump, I did the new o ring sleeves. I got them from the Pontiac Dealer.

[GT182]

I have read somewhere to use an antifreeze mix of 60% water and 40% antifreeze. Not to use a 50/50 mix in the summer months. 50/50 will not cool as well as a 60/40 mix. Antifreeze will retain heat where more water will help cool temps. Just my .

[george kujanski]

60/40 or 50/50, I doubt that it will make any difference at all Pure water will have a slight advantage.

George

[1967Tempest]

I think that it all boils down to air.

After the spacer mod is completed, and you have a new pump and sleeves with the smaller waterpump pulley than the crank etc... I think it all boils down to how many CFM's can you get through the radiator.

When I shut the car off and the temps start to rise, I can't touch the radiator cause .... its too hot. But if I turn the key to "ON" and let the electric push air in the radiator after the car is off, that part of the radiator is cool. Even after I shut the fan off.

Which by the way is a nice way to cool the car down after a run on a hot day.

1.After shut down let the electric fan stay on.
2.After like 10-20 minutes. Start the car and watch the temps come down 10-20*.
3. Do this until the temp after the coolant has made is way through the engine is around 180* The heat soak will then be pretty much gone.
4.The car will just slowly cool down from 180* 30min later car starts up and is purrrrfectly warmed up.

Hope I help even a little bit.
Dave

[aldbeir]

if you don't have a vanity plate i would just drill holes in the plate to lower it.

i used a plastic air dam off a 79 bonnie and made if fit so if your not worried about original use what you have. mounted to the bottom of the rad support.

[1967Tempest]

got any pictures of that??

[BVR421]

Originally Posted by 1967Tempest

I think that it all boils down to air.

After the spacer mod is completed, and you have a new pump and sleeves with the smaller waterpump pulley than the crank etc... I think it all boils down to how many CFM's can you get through the radiator.

When I shut the car off and the temps start to rise, I can't touch the radiator cause .... its too hot. But if I turn the key to "ON" and let the electric push air in the radiator after the car is off, that part of the radiator is cool. Even after I shut the fan off.

Which by the way is a nice way to cool the car down after a run on a hot day.

1.After shut down let the electric fan stay on.
2.After like 10-20 minutes. Start the car and watch the temps come down 10-20*.
3. Do this until the temp after the coolant has made is way through the engine is around 180* The heat soak will then be pretty much gone.
4.The car will just slowly cool down from 180* 30min later car starts up and is purrrrfectly warmed up.

Hope I help even a little bit.
Dave

Dave, good tip on the cool down
thats why many people wire their electric fans to a sensor and relay like all modern cars are. Fans come on at 185º regardless of the car running or not and fans shut off at 170º. Combined with a overflow recovery tank (not a puke tank) like factory cars of the 70s and later, the radiator stays full, no spitting up on garage floor and cool down after driving.
I wonder if a bypass would help or in the case of an old Pontiac a bypass type thermostat or some holes drilled in the t stat top to allow some thermal generated flow with water pump not turning after shutdown?
It sounds like you have a great cooling system

[GOAT490]

I believe the 428's had a 248deg idiot light! I never liked going over 210 and would get a little squeamish at 220 but I threw the belt more than once and went over 265 with my old 462. Didn't seem to cause any permanent damage. I try to keep my 497 under 200deg. I would think a mostly stock, well tuned 455 should be able to keep below 210 except if you're playing hard in the heat. Shrouds are VERY important and so are GOOD clutch fans.
PHILLYGOAT

[1967Tempest]

248!!!!!!!!
My car rarely sees 190*. The timing controller will be here today. Hopefully I can get some time this long weekend to hook it up. Thanks for all of the help!!

Dave

[wheelspin]

I have used many of the mods listed in the previous posts w/ success in my well-traveled Pontiacs. In July, we depart for Dayton OH and the POCI Nationals, traveling thru the hottest areas of the USA in triple digit temps in our 68 GP.

I would add:
Electric pusher fans mounted on front of radiators are a major flow restriction to a puller type engine or electric fan on the back side of a radiator. I pick one style or the other: engine clutch fan/ shroud, or PULLER electric fan/s.

A "severe duty" Hayden fan clutch (taxi/ police car type) produces signifigantly more airflow than the oe hd type clutches that came on the cars, but you will really hear it when it's engaged. The best test for fan effectiveness is to suspend a hand towel about 6" away from the front of the grill area w/ the fan operating (fan clutch engaged), and the towel should be drawn/ sucked onto the grill area. This test verifies the fan's action, and that the core area is sealed effectively.

Living in warm SoCal, I use 100% distilled water + Water Wetter for pump lube, and I install a sacrificial diode in the aluminum radiator for corrosion protection.

Future engine builds cooling tip: have your 40yr. old Pontiac heads and blocks professionally acid cleaned, which is the ONLY sure way to remove the decades old scale deposits that reduce coolant flow and require us to add aluminum radiators, add on fans, and oil cooling radiators to compensate for the insulating nature of the scale and reduced coolant flow.

Les

[BAD455TA]

I agree with the divider plate suggestion...I was having big time overheating problems and I clearenced the plates correctly, replaced the o-rings and sleeves...now I can sit in 110* Texas Heat and not even come close to the 220* infact it sometimes scares me how cool my car runs (just barely over 100) I take the temp from the intake and have checked the acuracy with an IR Therm. and everything checks out OK.

[Greg Reid]

Originally Posted by BAD455TA

infact it sometimes scares me how cool my car runs (just barely over 100)

That should scare you in my opinion. You might want to try another thermostat to get it up to at least 175 or so.

[dean7276]

[QUOTE=wheelspin;3658275]
I would add:
Electric pusher fans mounted on front of radiators are a major flow restriction to a puller type engine or electric fan on the back side of a radiator. I pick one style or the other: engine clutch fan/ shroud, or PULLER electric fan/s.

I agree in theory but I am running a 19" 7 blade clutch fan and I mounted an electric pusher fan just to see what would happen,it has brought my temps down 10-15 degrees city AND highway from 210 down to 195/200.
Go figure?