Engine temp on chevy small block

wag123 said:
Yep. I just noticed this in the picture. Thanks ARCO! The distributor advance pot needs to be connected to the vacuum port on the driver's side of the carb which is manifold vacuum. You have it connected to port vacuum.
Carburetor1, I asked you if you were getting 22-24 degrees of advance at idle with the vacuum connected, you said yes. Well... you fibbed. You never checked. A word of advice, if you want our help you need to be honest with us.
Click to expand...
Ahhh I fully understand it now...sorry I had things mixed up I'm still learning some things that's my bad. I'll check everything tonight again
 
The ported vacuum scheme was to make it easier to get a slow steady idle that daily drivers expect. Retarding the timing slows the engine down without having to completely starve it for air and fuel, which would be a touchy adjustment of the idle stop screw. It also helps with taking off from stops since as soon as the gas pedal is pressed the timing advances and the rpm immediately picks up.

The trade-off is that the engine is running inefficiently at idle, which is not good with a compromised cooling system as is the case here.
 
mk378 said:
The ported vacuum scheme was to make it easier to get a slow steady idle that daily drivers expect. Retarding the timing slows the engine down without having to completely starve it for air and fuel, which would be a touchy adjustment of the idle stop screw. This also helps with taking off from stops since as soon as the gas pedal is pressed the timing advances and the rpm immediately picks up.
Click to expand...

The first part I can agree with somewhat. The second part, not so much. Manifold vacuum has always given better throttle response for me. I set the mechanical curve to what the engine wants when accelerating.
 
Ok so if I have it set at 12deg with v advance unplugged and I switch it to manifold side, is this going to throw of everything I have the carb and timing set to
 
Carburetor1 said:
Ok so if I have it set at 12deg with v advance unplugged and I switch it to manifold side, is this going to throw of everything I have the carb and timing set to
Click to expand...

If set at 12° initial, it'll jump to 22° hooked up to manifold. (assuming it's a 10° canister) The idle rpm will likely increase since combustion becomes more efficient. This will accompany an increase in manifold vacuum. You may need to adjust the idle back down some and adjust the idle mixture screws.
 
RDY4WAR said:
If set at 12° initial, it'll jump to 22° hooked up to manifold. (assuming it's a 10° canister) The idle rpm will likely increase since combustion becomes more efficient. This will accompany an increase in manifold vacuum. You may need to adjust the idle back down some and adjust the idle mixture screws.
Click to expand...
Gotcha...I'll do it tonight. Switching to manifold and fixing shroud
 
Last edited:
Carburetor1 said:
Ok so if I have it set at 12deg with v advance unplugged and I switch it to manifold side, is this going to throw of everything I have the carb and timing set to
Click to expand...
So, while you have the timing light hooked-up, plug the vacuum advance into the manifold side, and check it again at idle with the timing light. Just use the timing light's dial to zero out the timing marks and read what your total advance is at idle off of the timing light setting.
You will have to readjust the carburetor. You will know right away after you hook to manifold vacuum. Check the timing again when you are done adjusting the carb to make sure you are still between 22-24 degrees BTDC.
 
One more question. Which notch do I want the fuel pressure regulator set at on carburetor when I switch to manifold
 
Oh, I think you mean the accelerator pump? If yes, you want furthest one in on the lever that doesn't cause a bog when stepping on the pedal. Every car is different.
 
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