Got a couple questions for you guys. I have a olds 350 (1972) in a pick up of mine. I have a new 4 core aluminum radiator, I flushed and cleaned the motor out completely, pulled all the freeze plugs so I could get next to the cyclinder walls. I have a 192 thermostat in it. And it's runs great right at 192 ish driving, but the second you stop it climbs fast. I'm honestly scared to get caught at a red light. It'll go up to 215 in just a short period of time.

I had a buddy of mine set the timing on the motor. I have a Petronix Flamethrower HEI. Could it be the timing is off and making it run hot? What is the best settings or degrees for these motors? Any help is appreciated, I just really hope this is the issue

 

A lot of people here will not agree, but I would go to a 180 thermo. If it runs at 180 and you get a 20 degree rise when stopped you're ok. That said, what are you using for a fan? A rise when stopped is due to loss of airflow.

 

Ive tried just about every thermostat there is, and they all run the same for me. I have a electric puller fan. 3000 cf.

 

A thermostat controls the minimum operating temp of an engine. The cooling system as a whole dictates the maximum temp. With your thermostat, it starts to open at the rating and is fully open probably around 195-198. It's normal for the temperature to climb higher in traffic and idle so your temp is not terribly bad, the idiot light comes on much higher than that. You didn't mention whether it stays at 215 and does not creep much higher for extended periods of time at idle or in traffic. What you want to see is the temp dropping down around the 195-200 range and maintaining when you start driving again.

As far as the timing, with an HEI you should be around 16-18 at idle and a total of 34-36 at 2800-3000 rpm with the vacuum advance disconnected, around 50 with it connected.

I also prefer a 180 degree thermostat, but there is nothing wrong with running a 195,

 

Fwiw I run a 165 in my dads pontiac olds power (350) and it reaches won't go past 180 . In my 72 I'm not currently runing a thermostat and I find it will get to 180 on hot days and creep to 190 at a light and on cool days its between 165 and 175 . I did have a 180 in that same 350 that in my dads car and it would go to 210 at a light and dip right back down to 190 185 while I cruised but at the time I had no shroud and no clucth fan assembly. I went to a 165 because I liked to keep it running cooler . Having a shroud and clutch also makes a big diffrence . That's just my experiences.

 

Retarded timing induces excess heat at idle.
My 403 with ~9.5 compression and comp cams cam greatly preferred manifold connected distributor vacuum advance just like the '65 425's used. With the car's stock tiny 307-engine radiator, old and crusty, the temp stays exactly right now. Even with 100 CID more engine running higher compression.

 

That is probably the issue. As m371961 Correctly stated, overheating at idle is airflow, overheating with driving is generally coolant flow. If it runs great while driving, the stat is fine. Put a big 7 blade mechanical fan with a shroud and I bet your issues are gone. Most aftermarket electric fans are not adequate.

 

Yep, it's hard to beat the capability of a good ole mechanical clutch fan. And they really don't use that much power to drive them.

 

And then what? You've told us only the first half of the story.

Does it continue to rise and rise and rise the longer you sit at a traffic light, or does it steady out in the 215 to 220 range? If the latter, there is nothing wrong. This is a perfectly acceptable engine temperature as the coolant doesn't boil until it gets over 250 F if the mixture is correct.

As has been mentioned, it is normal for the temperature to rise when idling and then drop again when moving.

 

Yeah, and when does the fan turn on?

 

Forget the thermostat. and get a bigger fan on it.
If you have a fan clutch, it is probably shot.

Get a new one and be done with it.

 

He said he is running an electrical puller.

 

is the fan equipped with a thermostatic switch?. If so is it located in the right place?, normally in the bottom or return hose tank in the radiator.
It's quite possible the fan just cannot shift air through the radiator quickly enough, in which case I suggest returning to the original fan and shroud as it left the factory with, after all it worked when the car was new.

Roger.

 

Not enough.

 

Agreed. I pretty much stated that in post #7 of this thread.

 

http://www.lbfun.com/warehouse/tech_...ance_Specs.pdf

"Does your engine require additional timing advance at idle in order to idle properly? Radical cams will often require over 16 degrees of timing advance at idle in order to produce acceptable idle characteristics. If all of this initial advance is created by advancing the mechanical timing, the total mechanical advance may exceed the 36-degree limit by a significant margin. An appropriately selected vacuum advance unit, plugged into manifold vacuum, can provide the needed extra timing atidle to allow a fair idle, while maintaining maximum mechanical timing at 36. A tuning note on this: If you choose to run straight manifold vacuum to your vacuum advance in order to gain the additional timing advance at idle, you must select a vacuum advance control unit that pulls in all of the advance at a vacuum level 2” below (numerically less than) the manifold vacuum present at idle. If the vacuum advance control unit is not fully pulled in at idle, it will be somewhere in its mid-range, and it will fluctuate and vary the timing while the engine is idling. This will cause erratic timing with associated unstable idle rpm. A second tuning note on this: Advancing the timing at idle can assist in lowering engine temperatures. If you have an overheating problem at idle, and you have verified proper operation of your cooling system components, you can try running manifold vacuum to an appropriately selected vacuum advance unit as noted above. This will lower engine temps, but it will also increase hydrocarbon emissions on emission-controlled vehicles.

Running straight manifold vacuum to the vacuum advance control unit is recommended formost applications where emissions are not an immediate concern."

 

Same thing happened to a guy on the big block part of the forum, put in a thicier radiator and his slow speed temps skyrocketed. Takes a more powerful fan to pull air through the larger rad core.

I'd look at a new fan before messing with the vacuum stuff, but you should get that working to if the problem persists