[ichabod]

Just got my 65 tri-pwr 389 rebuilt. Had the distributor recurved. I have 77 heads, 3 row rad.(recored),160 stat.,new rebuilt pump. 744 cam. 4:33 gears.Intial timing is at 12, 36 total. First time out the temp. went to about 195 on hway. soon as I slowed down in traffic 210-215. I run 100LL av gas due to 11:1 comp. Will the temps come down some after some additional breakin time.

[Txbobcat]

I would think you could expect minor cooling after break in but in this cool weather that sounds pretty warm to me. I expect you do have a fan shroud on?

[Never Enough Power]

Have you tested the colant temp in the radiator? Your gauge could be off, so before you go crazy trying to drop the temp verify that the gauge and sender are correct. Let us know what your readings are.

[ichabod]

Yes,also fan shoud 7 blade fan. Your right the outside temp. was only in the 50's.

[ichabod]

The GTO runs the Tri-pwr setup. It has always run around 185- 195, but aronnd town temp would drop to 180-185. I had the distributor recurved and used in the old motor before the rebuild that's when I noticed an increase in temp by 10-15 degrees. I had hoped with the recored rad. and new(rebuilt) pump the new motor would operate cooler. I get nervous when she creeps over 200. As everything is close to stock what were these cars running for temps 40 yrs. ago. Can you use both electric and engine driven fan? The motor is pretty tight right now so I was hoping that with some mileage she cool down. Thanks.

[mike nixon]

what temps did the car run before the recent work? with the 4:33 gears,11:1 compression and highway speeds the car is going to run warm.

what size carb are you running ?

the idle temps indicate an airflow problem at low speeds.

if it were mine i'd think about a good aluminum radiator and a high cfm, temp controlled electric fan as well as the engine driven unit.

i'd also invest in a coolant recovery tank.

if you plan on driving the car in hot weather you'll need all the capacity & airflow you can
get.

btw: a higher temp thermostat controls the temp up to the opening point [170/180/195 ect] , after that it's up to the rest of the system to keep the temps below that point.

mike

[Hot Rod Ken]

One of the tricks that I have seen done is to drill an 1/8th inch hole in the flat area of the T stat.This lets any air that is trapped out of the engine ,and the T stat gets a better sense of the water temp to open and close sooner.
This can realy help if your pump is adding some bubbles to your system.

[David Jones]

You need more radiator. If its to hot both at idle and cruise in 50 degree weather your lacking in cooling capacity.

http://kurtspontiac.homestead.com/DavidJones69GTO.html

[ichabod]

Just got my 65 tri-pwr 389 rebuilt. Had the distributor recurved. I have 77 heads, 3 row rad.(recored),160 stat.,new rebuilt pump. 744 cam. 4:33 gears.Intial timing is at 12, 36 total. First time out the temp. went to about 195 on hway. soon as I slowed down in traffic 210-215. I run 100LL av gas due to 11:1 comp. Will the temps come down some after some additional breakin time.

[Heybuck]

I think you should be using the HIGHEST temp thermostat you can.

The stock radiator should be fine. A huge radiator is not always the answer.

If the thermostat cracks open too early (at 160), the engine is pumping the coolant through the radiator FASTER than the radiator can dump the heat into the atmosphere.

So, the coolant is still too hot when it enters the engine again.

A high temp thermostat SLOWS the coolant rate to the point where the coolant has dumped its heat out through the radiator BEFORE it gets called back into the engine.

PS, make sure you have a spring in the top and bottom radiator hose.

Experiance is that marvellous thing that makes you recognise a mistake when you make it again.

[gtoguy1967]

do you have a good clutch fan? sounds like when the air is not moving past the radiator is when it gets hot. might try a 5797 hayden cluth it is a heavy duty one. i found mine at pep boys for around $70 i think. i had a 160 stat in my car and it seemed to run cooler and more consistant with a 180.
Don

some times when you race with squirrel's, you get your nut's cracked!

[head #96]

You need a 4-core radiator, temps should in the 180 zone.

[autobahn]

Befor spending a lot on radiators , make sure you devider plate in your water pump is in " tune" . that is with in .030 of the impeller . I went from 210 to 180

[autobahn]

Better spending a lot on radiators , make sure you devider plate in your water pump is in " tune" . that is with in .030 of the impeller . I went from 210 to 180

[Geoff]

Finding that the temp increases after slowing down for traffic after highway speeds occurred in EVERY car I owned. If you are doing 70 mph, your engine is producing twice as many power strokes [ and heat with it ] then it is in traffic at 35 mph. But the water capacity doesn't double at 70 mph does it, so the engine builds heat & becomes a heat 'storage' tank & dumps the heat when you slow down.
First, you need a high flow 160 stat. The faster the water flows, the quicker the engine cools. The 'slowing the water' is an old wives tale that has been thoroughly debunked. Have a look at cooling sites that do their own research, like Stewartcomponents, C&R radiators, etc. I would increase the water pump pulley size size to give the pump/fan 30% overdrive. Your 4.33 gear is going to make additional heat.
A good 19" flex fan, such as a Flex a Lite or the original Pontiac Ram Air flex fan is a good idea. They cool better than clutch fans because they don't have a clutch that slips. With the 744 cam & 389, you would need alot of timing at idle to smooth the idle & help with idling heat, so I would get a Crane adjustable vacuum advance unit & connect it to manifold vacuum. The vac adv, when it is connected to manifold vacuum, helps the engine run cooler because it makes the engine run more efficiently.