[DiamondJim]

Put a few gallons of race gas in and see what that does. -Jim

[70GS455]

10.6 static compression can be fine. Static CR is not always the issue, it's how late the intake valve closes (among other things) that will determine cylinder pressure. A late closing intake valve (due to a big cam) can bleed off cylinder pressure to a level that will support 93 octane or whatever. Now, if you have a small cam with 10.6 static then that may be an area of concern.

[YVEYANT]

Try checking the obvious things..
How is the tension on your belts? when you hit the gas does your belt flex (does it seem to go sideways when the rpms go up?) if so maybe your pulleys are not lined up properly or a pulley might be bent.
Is your thermostat opening?
Is the water pump in good working order, did you remove it to check the internals? Check your hoses going to the radiator particularly THE BOTTOM HOSE, does it collapse when under pressure? They are notorious for it. Does it have a spring in it as it should? Many of the new hoses do not come with new springs, you have to use your old one, it is there because they are known to collapse and close when under pressure if the spring is not present.
Also, whether it is new or not, if you have a radiator shop by you, have your radiator pressure tested and blown out, I have seen new radiators have small traces of metal blow out of the tubes that would certainly clog it up. Also when pressure tested, if it fizzes air it will overheat. I had one that was fizzing air when tested, but even at the highest pressures would not leak antifreeze or water, hard to catch but it was my problem.
Where you live, do you have hard water and is that what you used to fill your radiator up with? If so hard water contains a large amount of minerals particulary high levels of iron which could clog your radiator up in no time.
Did you try a different antifreeze/mixture?
Is the Royal Purple compatible with your antifreeze? Many of those products say on the bottle they will NOT work with certain antifreezes and could result in overheating.
Some things to think about, hope this helps.

[DiamondJim]

Originally Posted by 70GS455

10.6 static compression can be fine. Static CR is not always the issue, it's how late the intake valve closes (among other things) that will determine cylinder pressure. A late closing intake valve (due to a big cam) can bleed off cylinder pressure to a level that will support 93 octane or whatever. Now, if you have a small cam with 10.6 static then that may be an area of concern.

With the small cam he is running his DCR is probably 8.5(or more) with 200 psi of cylinder pressure, IF, the 10.6 static is correct. Maybe he can post intake closing, OR just try some race gas and see what that does. Even with proper quench and a large cam, 10.6 with iron heads is pushing your luck. -Jim

[redfirebird]

UPDATE
I installed a smaller pulley on my water pump last night I went from an eight inch to a six inch. The outside temp had fallen to around 75 but I ran the car anyway. It heated up to 204 and then I turned my auxiliary fan on. In the next 10 minutes I went to 206. Five minutes later it was down to 204. I let the car run about 30 minutes when I shut it down my temp was 192. I think my over heating problem may be gone but I need to wait for a warmer day. If you can trust the weather men they clam mid 80's next week I will try again hopefully it will do the same. I just want to say thanks to every one who responded with suggestion I do appreciate the input.


Keith

[YVEYANT]

Glad it all worked out, now get out there and enjoy that beast!!

[Steve Barcak]

I am glad to see you are making some progress but, with all the people who answered here, no one suggested running a cooler thermostat.
I cannot understand this. Do you realize what a thermostat does? It is CLOSED, until a selected temp is reached, and then it OPENS.
With a 180, your system does not flow until it reaches 180 or thereabouts. With a 160, your system starts flowing, and thus, COOLING sooner. Would common sense make everyone think this would be desireable? Especially if you are running hot?
Why would you want to DELAY (temp wise) the effectiveness of your cooling system when you are running hot?
Try a 160 stat. Use the high flow Robert Shaw or Mr Gasket version and be sure to cut a "V" into it to help eliminate air bubbles.
This is a simple thing to do and inexpensive thing to try. There is no way a 160 stat can make you run hotter than a 180 unless something is defective.
I live in the heat of the Arizona desert and have much experience with cooling and Pontiacs. You are in Wisconsin? Something is wrong.

Again, I wish you the very best with your Pontiac.

Steve Barcak www.pontiacheaven.org
"Real Pontiacs only...no corporate nonsense!"

[kilahcup]

My experience with using a 160 thermo is that the engine generates too much heat. The temp doesn't stay below 160 for long, and as a result the t-stat winds up open all the time. This in turn means the coolant spends very little time in the radiator and never actually cools off very much. The result is runaway engine temperature. I even have this problem with 180 thermos.

[tempest455]

I run 13.5:1 comp on the street, with a 700 HP motor and it never gets above 180F! Most of the time it hovers around 160F.

The things I found that worked on my car in order of importance:

1. Ditch the copper/brass radiator and get a good 2 core Aluminum. This may drop the temp by 20 deg alone. It did on my car and I had a custom 5 core high efficiency radiator that was "gauranteed" to keep this thing cool.

2. High flow water pump over a stock. And or/ impeller mod thats been discussed here.

3. Speed up w/ a pulley change (you did that).

4. Cooling line(s) to back of the heads from the water cross over.

5. Use water only in the summer with a corrosion additive. Do not forget in the fall!

6. Make sure its timed right.

7. Lastly, verify the temp with a digital probe to make sure your gauge is correct!