I had this problem for years with my 1979 Cutlass. It turned out to be a clogged radiator like Joe P wrote. I stubbornly refused to believe that since at that time the rad was brand new. Well, it turned out to be an aftermarket piece of garbage. I finally broke down and replaced it with an aluminum radiator, no more problem. In fact it almost runs too cool now.

I have 3 spare radiators I was going to sell for scrap metal, but as they are the older ones NOT having the plastic side tanks, I'm going to pay to get them all re-cored and either sell them or continue to hold onto them for spare(s).

 

It seems like the engine temp issue is no longer an issue. I was out driving yesterday and the temp didn't get above 190 even when it was close to 100 out. Hopefully I can take it on a longer drive this weekend or next and get a better idea, but the issue where I was in a particular gear for a period of time and the temps creeped up seems to not be happening. I'll also get the RPMs up to 3500-4000 to make sure my timing is all in and see if I can/need to adjust the initial timing some more.

I'll tell you this has been quite the learning process and I appreciate everyone's input/advice.

 

Had another go around with the timing this weekend, think I might have gotten it all worked out. Like others had mentioned, I went ahead an rechecked my timing and made sure my RPMs where up between 3500-4k, they were around 3900 on my timing light and my timing was no longer advancing. Actually, I was watching the timing mark and it appeared to stop advancing at around 3300-3400 RPM, not sure if that is too low or not. My initial timing is set at 14 degrees, mechanical is set at 21 degrees, which puts be all in at 35 degrees. I hooked up the vacuum advance canister to the manifold vacuum port on the carb and reading up on that as well, looks like that provides an additional 10 degrees of timing at partial throttle, which adding everything i'm at 45 degrees. Engine runs strong now, I notice a little more performance in first and second now, but sounds/runs good through all gears, no knocking or pinging when getting on her up to 4k RPM and up to 75mph. Had to tweak the RPMs when i connected the manifold vacuum, not sure if it's normal but it add some RPMs so i brought it back down to about 750-800 and tweaked the idle mixture screws and i've got about 20-21 inches of vacuum at idle. Hoping i'm doing everything above correctly and that I think i'm done with the timing, next to check fuel pressure and float level, figure out why i'm getting fuel on the manifold after i drive her.

thanks again for all the help with timing, i have a much better understanding of it now.

 

Glad you got it running better.

 

Congratulations on timing success.

As you get into the carb gas leak issue, please post a picture of not just the carb, but leak location / condition. Quadrajets, Holleys, and Carter carbs have different places they can leak. It’ll help us help you to know which carb you’ve got and where the leak is.

When working on fuel lines, it’s important to use line (flare nut?) wrenches and not an open end or crescent wrench. The latter don’t distribute torque evenly and can create leaks or make them worse. Cleanliness matters a lot in carbs. Dirt can block tiny air or fuel passages, impede choke mechanisms and other ills. Clean carbs are easier to troubleshoot too.

Fire Safety
Gas on a hot intake can lead to an engine fire. Have an extinguisher in the car. Also if your engine intake wiring insulation is cracked or frayed, an electrical short can ignite fuel on the manifold.

Common Qjet leak sources
If you’re talking about a Rochester Quadrajet, here are some common spots to begin the gas leak hunt:

• Fuel line to fuel inlet nut junction. I.e. from your steel or rubber line from the pump to the big nut that goes into the carb. Generally no gasket here. Flare fitting is the seal, maybe with touch of teflon paste, not Teflon tape.
• Fuel inlet nut to carb main body junction. I.e. the big nut that connects to the float bowl. It should have either a metal or nylon gasket. Be careful not to overtighten or you can strip the threads and ruin the carb main body
• If your fuel comes in the passenger side, not the front, the freeze plug where the fuel turns 90 degrees to go into the needle & seat can leak from repeated heating & cooling. JB weld might temporarily help, but it’s a sign that you may want to replace the carb with a center inlet rebuilt unit. I consider center inlets much safer, personally.
• Float level too high. I usually set mine to 5/16”, but there’s a spec, so best to go with what your rebuild kit recommends as a start
• Airhorn gasket torn/missing/not sealing. Check the airhorn on straight edge for flatnesss corner to corner on the underside. Get & install a quality rebuild kit. I like Cliff Ruggles kits and those from Qaudrajets.com
• Fuel pump rod hole in the air horn. I don’t think there’s a seal for this, but it means you need to trouble shoot the fuel pump circuit to ensure gas is going through the squirters and not spewing up out the air horn hole.

There are lots of threads here on carbs. They are fascinating devices and fairly complex. You might start a new thread & let this one stay focused on timing.

Hope this helps
Chris