Engine temp on chevy small block

[Carburetor1]

If it has an original harmonic damper, the timing marks may be worn off or the damper could've moved slightly. Something like that could be why it was difficult to set.

If it's installed at 8° with no vacuum advance (or set to ported vacuum) then that is your issue. Idle likes the timing in the 20-25° range, sometimes higher. At idle, you have low cylinder pressure and a good bit of reversion. This means a slower flame propagation requiring more spark advance. When timing is late, the mixture is still burning when the exhaust valve opens which causes exhaust gas temperatures (EGTs) to spike. The coolant in the heads flows around the exhaust ports so a good bit of that heat ends up going in the coolant. The late burn also means a higher amount of exhaust reversion into the intake port during overlap and a higher amount of residual exhaust gases on the next intake cycle. That means less efficient combustion with dilutes further and so on. Average cylinder temperatures are higher, dumping more heat through the cylinder walls.

My process for finding ideal timing is similar to what is stated above. I like to use a 15° vacuum canister and set the initial timing at 5°. I like to get the initial timing as low as I can so it'll crank over easier. Then let the vacuum advance add the timing once it's fired up. Starting at 5° initial, I hook up the vacuum advance to manifold and verify 20°. (5° initial + 15° vacuum) Then I hook up the vacuum gauge and gradually bump the timing until I find the highest vacuum and/or smoothest idle. I let the engine tell me what it wants. I then unhook the vacuum advance to see where the initial timing is so I can start mapping the mechanical curve.

When moving the timing around, the idle rpm is likely to change as well. This is due to the change in combustion efficiency and vacuum. You'll likely have to adjust the idle rpm and possibly the idle screws on the carb to compensate. You may need to move the timing a couple degrees, adjust the carb, move the timing, adjust the carb, etc... to keep things consistent. It requires some patience to dial it in, but it'll run so much better and cooler once you do.

Ok..the man who set timing did everything correct as per initial setup. If I go off of what he already has it set to with an adjustable light can I just set the dial to 22 with vacuumed advance hooked up and adjust timing to zero out that way? And then tune the carburetor with vacuum gauge

 

[Carburetor1]

Update...Timing was at 8degrees and I shifted to 13 hooked vacuumed up then tuned carburetor and it smoothed out motor and exhaust sounds much better. Got vacuum up to 20. Still gets to 210 on temp.

 

[ripcord]

Update...Timing was at 8degrees and I shifted to 13 hooked vacuumed up then tuned carburetor and it smoothed out motor and exhaust sounds much better. Got vacuum up to 20. Still gets to 210 on temp.

Might be 'bout time to post some pictures of your fan/shroud/radiator setup

 

[Chris142]

Might be 'bout time to post some pictures of your fan/shroud/radiator setup

This. I wanna see it

 

[Powerglide56]

This. I wanna see it

I own virtually the same car-since 1978. But it’s a (99%) bone stock 56 Bel Air with 265 v8 and Powerglide automatic. The small shroud helps in slow speed traffic on a hot day. Barely noticeable under the hood as far as a non-stock modification. Lots of good advice above, but I’m compelled to chime in. The factory service manual specifies a 160 degree thermostat. A 160 thermostat STARTS to open at 160 degrees Fahrenheit. It won’t be fully open until about 183 degrees. That is where the motor will run if all else is right. I’d start there.

 

[Carburetor1]

Might be 'bout time to post some pictures of your fan/shroud/radiator setup

The fan a little too far in the shroud and is pushing air up between the radiator and shroud. The fan has 6 aides and in good shape. It is pulling air through the radiator because it will hold a piece of paper to it. Going to shift it back a little bit and try it. Also going to remove thermostat and flush system out good.

 

[Chris142]

The fan a little too far in the shroud and is pushing air up between the radiator and shroud. The fan has 6 aides and in good shape. It is pulling air through the radiator because it will hold a piece of paper to it. Going to shift it back a little bit and try it. Also going to remove thermostat and flush system out good.

The fan needs to be 1/2 to 1/3 sticking out the back of the shroud. If it's too deep in the shroud it will cause turbulence instead of sucking air.

 

[Carburetor1]

I have thought about that

 

[Carburetor1]

The fan needs to be 1/2 to 1/3 sticking out the back of the shroud. If it's too deep in the shroud it will cause turbulence instead of sucking air.

When I adjust it tonight I will post a photo. It did stay at 190 for a min but then went back to 210 at idle. I just can't believe that it is still getting hot.

 

[Chris142]

When I adjust it tonight I will post a photo. It did stay at 190 for a min but then went back to 210 at idle. I just can't believe that it is still getting hot.

Well 210 is not "hot" for that engine. I'd start to worry about 240.

 

[PontiacHO]

Where is the temp gauge sending unit? If in the head and you have headers that might be the reason for the higher temp at idle. If the sending unit is in the intake then carry on…

 

[ARCOgraphite]

If its stays at 210 and doesn't keep climbing, I don't see a big problem.
Temp gauge may be off. the IR gun reading can be flaky depending on the surface colour or finish.

It concerns me that the mechanic was having a hard time setting timing. When you set it did the mark jump around?

You could have a worn cam sprocket, a sloppy mechanical advance, and or a worn dist gear.

Have you removed the T stat and plopped it into a glass of 190 water to see if it opens?
I would assume you have a mercury or alcohol thermometer to set water temp.

 

[Carburetor1]

Where is the temp gauge sending unit? If in the head and you have headers that might be the reason for the higher temp at idle. If the sending unit is in the intake then carry on…

Not sure will look tonight

 

[Rob_Roy]

Ok..the man who set timing did everything correct as per initial setup. If I go off of what he already has it set to with an adjustable light can I just set the dial to 22 with vacuumed advance hooked up and adjust timing to zero out that way? And then tune the carburetor with vacuum gauge

You should set the initial timing with the vacuum advanced disconnected. Total mechanical advance for that engine should be about 36 degrees, you can check that with your timing light with the engine at 3000-4000 rpm or so (depends on which advance springs installed in the distributor). The vacuum advance should be connected to ported vacuum - this gives additional advance during low load driving conditions.

As for the operating temperature, where and how are you measuring it? It is not uncommon for the sensor in the cylinder head to read a bit high. 210F is a bit higher than what most people like to see, but it is not considered overheating.

 

[Carburetor1]

If its stays at 210 and doesn't keep climbing, I don't see a big problem.
Temp gauge may be off. the IR gun reading can be flaky depending on the surface colour or finish.

It concerns me that the mechanic was having a hard time setting timing. When you set it did the mark jump around?

You could have a worn cam sprocket, a sloppy mechanical advance, and or a worn dist gear.

Have you removed the T stat and plopped it into a glass of 190 water to see if it opens?
I would assume you have a mercury or alcohol thermometer to set water temp.

Nothing moved around the engine ran consistently when advanced timing. Will remove thermostat tonight and flush system again the water is looking a little rusty

 

[wag123]

The vacuum advance should be connected to ported vacuum - this gives additional advance during low load driving conditions.

Negative!
The vacuum advance needs to be connected to manifold vacuum on all pre-emission controlled engines. This is how it was set-up at the factory.
The manufacturers went to port vacuum advance when the exhaust air injection came out.

 

[wag123]

When I adjust it tonight I will post a photo. It did stay at 190 for a min but then went back to 210 at idle. I just can't believe that it is still getting hot.

It looks like you made some progress. 210F at long term idle in hot weather is good, as long as it is stable. It might come down a little when you move the fan back.
Going with a colder thermostat is not going to help you. If the car is getting hot with a 180F thermostat it will still get hot with a 160F thermostat, it will just take a little longer to get there.

Update...Timing was at 8degrees and I shifted to 13 hooked vacuumed up then tuned carburetor and it smoothed out motor and exhaust sounds much better. Got vacuum up to 20. Still gets to 210 on temp.

If you are getting a total of 20 degrees advance at idle (I assume this is what you meant when you said "Got vacuum up to 20") you need to adjust the vacuum advance pot to give you more advance. You need to aim for 22-24 degrees of advance at idle. How you do this is by inserting a small allen (hex key) wrench (I think that it is 3/32") into the vacuum port on the vacuum advance pot (if it is adjustable, most were in points ignition vehicles). If it doesn't have an adjustable vacuum advance pot you should obtain and install one.
If you get pinging when cruising in 4th gear at lower RPMs when trying to accelerate or if the starter struggles to turn the engine over, you need to back-off on the static advance a little, and then compensate with a little more vacuum advance at idle (you still want 22-24 at idle).

 

[Rob_Roy]

The manufacturers went to port vacuum advance when the exhaust air injection came out.

I don’t disagree with you on that, but this is clearly not the stock engine for this car. My experience with SBCs (especially ones with aftermarket cams) is that they do well with ported vacuum advance. Your mileage may vary - nothing wrong with trying it both ways (will need to adjust timing and carb accordingly, and see what drives best.

 

[Rob_Roy]

Nothing moved around the engine ran consistently when advanced timing. Will remove thermostat tonight and flush system again the water is looking a little rusty

Removing the thermostat is helpful for flushing the system, but you should replace it afterwards.

 

[wag123]

I don’t disagree with you on that, but this is clearly not the stock engine for this car. My experience with SBCs (especially ones with aftermarket cams) is that they do well with ported vacuum advance. Your mileage may vary - nothing wrong with trying it both ways (will need to adjust timing and carb accordingly, and see what drives best.

It doesn't really make any difference in terms of overall performance, except when there is an overheating problem at idle. The only time that this comes into play is at idle. Manifold vacuum is the way to go when addressing a problem like what the OP is experiencing.