You also need to see what your maximum timing is at. I use a digital timing light with adv/ret feature to know where it's at and at what rpm
How are you determining when to stop adding coolant when it's cold? Normally the Mustangs like to have the internal radiator fins covered by about 1/4 inch of coolant. Much more than that will end up spewing out the overflow. Have you run it for a while after you see the coolant circulating with the radiator cap off and added coolant as needed? This will eliminate air pockets in the system.So I took it out for a drive and it gets hot very quickly. I have a given it new 180 thermostat, new water pump, new aluminum radiator, timing is 6btdc (was 10 then 8 now 6) and it’s still overheating the same. AFR gauge is 10.7 at idle 800rpm and shows 11.5 while driving steady at 55mph. Cold It starts up and runs no choke (manual choke off). Hot also starts easily just turning the key with no pumping the gas or excessive cranking and will idle no issues except the getting hot and blowing out coolant.
I drove it 10 miles and it ran ok, a bit sluggish on acceleration but cruising along at 55 with ease. Sat at just under boiling the whole way.Spewed out coolant from the overflow when I turned it off. Let it sit for a few hours and topped off the radiator with almost a gallon of water and drove home and it ran the same as it did on the way out and dropped a puddle of coolant when I got home. If I can figure out this overheating bit it might be a good daily driver.
Glad to hear you got that handled. There's a big difference in driving mine in the Spring and Fall from the Summer, especially when I'm stuck in bumper to bumper traffic. It hasn't overheated yet and I have a new radiator and my block was tanked and cleaned but it sure gets unhappy in traffic; runs rough and shakes at idle more than normal.All is good. Have taken a few drives in this heat and it’s running good and not getting overheated. Just need some wheels and tires and lower the front end a bit to get it from takeoff to flying level and it can be my daily driver for a while.
So can you narrow down what you did to fix it??All is good. Have taken a few drives in this heat and it’s running good and not getting overheated. Just need some wheels and tires and lower the front end a bit to get it from takeoff to flying level and it can be my daily driver for a while.
YesSo can you narrow down what you did to fix it??
Because choke is required after cold start for more than a half minute, and because of the idle speed difference cold/hot, either the idle circuit on the carb is too lean or more likely a vacuum leak. One way or other, idle is too lean.So I went for a 15 mile each way drive.
So let’s start out with the settings. Cold it starts and will idle with a bit of (manual) choke and after a few minutes idle with no choke. High idle in park is 800 low idle in drive is 650. It runs good and can keep up on the hiway but after driving a while thd low idle goes up to 900 and thd high idle is 1400 so when I got to where I was visiting it was reving a bit high. Left it sit for 2 hours while I was visiting and it started just fine with idle back down at 650/800 and after driving the 15 miles back home it was 900/1400. AFR is 12 to 14 I did the timing by advancing it til it pinged on acceleration and backed off a few degrees. Other than that it runs good. I have been shutting it off in drive then putting it in park just so it not reving hard when I shut it off.
The idle mixture goes richer when idle speed is reduced.Not bad
As for the idle, it might change with the idle speed change
YesWhat I don’t understand in your description is that after driving the 15 miles home you describe a low idle of 900 and a high of 1400. Are you saying that it has a high idle as well as a low idle after it has warmed up. Is It hanging high?
Oh, ok... So it goes up to 1400 and stays there. Going from 750 to 900 and staying at 900 is the normal thing on mine but if it's shooting up to 1400 and hanging, that does sound like some kind of vacuum leak especially if the carb is closed. It sounds like something is changing shape due to heat and allowing the vacuum to pull in extra air.Yes
When after driving a few miles the idle goes up and stays up until the engine cools then it will resume at the correct idle speeds until it “gets hot”. There is no adjustment left in the carburetor to lower the idle. The throttle shaft had no more movement and the throttle plate is as closed as it can get. There only way I am able to bring the idle rpm down is to back off the timing.