Hi Guys,
New here and thought I would ask for help. I have a 67 Chevelle SS 396, 4speed matching numbers car. The engine has a small cam Edelbrock intake, holley carb.The car runs well off of idle and gets hard to start after a run of any type that get the engine warm. Timing is set at 14btdt. In traffic like in the dream cruise coming up real quick I get very hot very quick. It has a good flowing radiator four core copper, edelbrock pump and a 160 thermostat. The car doesn't want to idle below 1100 rpm's and I am looking for some pointers to get this car where it should be. Any help will be welcome.
Thanks in advance,
Bob

How hot does the engine get? Hard start how, cranks over slowly or just won't fire up.

With a mild cam it should idle well below 1100. I would start with that problem. Check for vacuum leaks, that could keep you from getting the idle down and will also cause the engine to run hotter. See if you can bring your initial timing up some. If with a relatively mild cam you may be able to go 16* or even 18*, that will also reduce engine temps. If you're idling at 1100 and timing is at 14* you may be seeing a few degrees of mechanical advance. That will limit your total advance to less than what you should be running. The initial timing is set with vacuum advance disconnected and plugged, right?

Like I said start with getting your idle down where it should be, vaccum leaks, carb adjust and timing. Then see if you still have a problem.

I have seen the temp as high as 230 once. But 215 is not unusual to hit. I have checked for vacuum leaks and found none. Timing I will do this weekend. Distributor is a high performance GM type with no points.I can see the gas boil after a run down Telegraph. Not hard just cruisin. My hooker headers are not coated so I know that raises temp underhood. It turns over but takes a while to fire when hot. New battery this year. Thanks for the response...
Bob

215* is too hot and 230* is really too hot. With a 4 core rad in a 396 it should be running 160* since that's the thermostat you're using. I would up that to 180* once you get things sorted out.

I'm running a GM HEI in my 454, mild cam, 18* initial. It idles fine at 800 rpm. I would disconnect the vacuum advance and set the timing up a few degrees, 2-4. Hook the vacuum advance back up and see if you can bring the idle back down. See if you can get it down under 1000, hopefully less since it's a stick. You should adjust your idle mixture too once you get the idle rpm's down where they should be. If you can get the idle down check the timing again, it may have dropped some at the lower idle. If so, adjust it back up to 16*-18* again. You'll have to verify that your engine can handle that without pinging. If not you'll have to back it off some.

Have you checked your vacuum at idle? With a mild cam you should be at 15 or above. Retarded timing and a lean fuel mixture (vacuum leak) will both cause the engine to run hotter. A propane torch is a good way to check for vacuum leaks at base of carb or intake manifold. Just turn on the gas, not too much, and blow it around the base of the carb and along the intake to head gasket. If you hear the engine rpms change you found a leak. Your hot start problem sounds like it's just due to the engine running to hot and not anything electrical.

You say it gets hot fast,what are idle and cruise temps and howong does it really take to hit those temps?

Have you used an automotive type AC service thermometer to verify coolent temp thru rad filler neck directly in the coolent to verify temp gauge is readding close to or right on what your seeing in the rad filler neck?

Haveyou purged all air from cooling system?

Also,a mech type temp sender gauge/sending unit with metal cable installed in head by ex valve and ex manifold .

They generally read approx 8-10 deg hotter then the rest of the motor is seeing at that same time due to proximity to a known hot stop in head by ex valve & manifold. (PHEW/LOL!!!)

And the metal cable on the sneding uint can also get heat soaked fromead/ex manifold so insulate it from the head back to firewall ,doing that will also reduce temps a few deg on the gauge if running a ,ech temp sendr along with mech temp gauge.

Even the mild eddy cams i have dealt with bbc's need at least 18 deg base timing.

Also ,make sure the vac adv is hooked to full intake vacuum all the time .

And as already stated too in that case you will need to setup mech adv in dist for approx 18-20 deg mech all in by approx 2800rpms.

Then 18 deg base + 18-20 deg mech = 36-38 deg total by 2800rpms.

Also,i have had issues with new or almost new t-stats being defective and others here in t/chevelle have also posted same issue with some of the t-stats mfg these days.

So replace that before going any futher because you dont want to find later after going nuts trying to diagnose this problem that a $10 t-stat was the isuse the whole time.

Why am i saying concerning the t-stat is becasue it just happended to me with my mild 396 with a slightly use t-stat wasnt fully opening up restricitng coolent flow at higher rpms /higher cruise speeds. But at idle & lower 50-60 mph cruise it was fine,it just heated up when criusing at 65-70mph at approx 3k rpms due to the reduced coolent flow with partially stuck/not fully opening hi flow 180 deg t-stat & hi flow milodon w-pump.

Also,what radiator are you running and age of it, what type fan (std 4 blade or HD-AC type 7 blade clutch fan) ,and if running a fan clutch is it std or hd thermostatic type and whats its age?

Are you running a fan shroud?

Lastly,you say it starts hard when hot,do you mean the motor spins over a lot before the motoractually starts up? Thats generally issues with tuning & or carb possibly dumping some fuel into motor after shutting it down because the motor running hotter then it should ?

Or do you mean when you try to sart it up hot the start barely turs over like the batter is weak going R R R very slowly then finally starts which isa totaly different issue?
Thats generally an issue with a weak starter thats either trahsed form heat soak due to no starter & solennoid heat shield,using a non hi trq or just a tired hi trq starter needing to be rblt,an old weak and or low CCA battery ,possibly a weak alt esp if running a low output 37-42 ampatl that doesnt put out much umph at idle andor lower engine speeds thats really an issue when running additional electrical accessories then car came with,and or dirty-corroded-rusty-loose-connections & grounds in starting & charging system along with possibly new paint from recent resto/detailing work affecting grounds & in generall any/all connections in electrical/starting/charging systems.

BTW,I run approx 18-19 deg base timing with my mild 396 /9.7-9.8 comp with a totally stock starting & charging system(except for stock 37amp alt upgrd to approx 70amps) and it always starts fine when hot for the 30+ yrs i have owned the car with it on the road every one of those 30+ yrs too.

Scott