first just a back ground of what i got and and done. 1977 F250 4x4 460BB c6 trans, 160 t-stat with direct mount flexlite fan. I recently gotten a cooling issue after a year and half no problems. my temperature tends to spike every now and then up to 220*. I havent had any problems for about 1 1/2 years. i dont mind the spike evey now and then on intial warm up but lately Ive noticed that my temperature is running around 190* on interstate and around 170* on in town driving. up until now the numbers 170* all the time. year and half ago. coolant level is perfect. I replaced water pump, thermostat, radiator 1 1/2 ago and it ran perfect until now an i also replaced the temperature gauge and sensor 3times and the all read the same. The sensor is in the left front corner of the manifold. I added to two 10" pusher electric fans last week on front to help out during idle and excessive temps. Ive removed the t-stat and checked it in a pot on the stove and it opens around 160* degrees, but i noticed it doesnt open evenly. It opens really on one side. Meaning when its open its at an angle. Anyways i figured that was ok. So i reintalled it. I had to rebuild my carb and add a power valve in the secondary to the correct size since it had a plug instead of the valve and i rejetted the secondary down from 76 jets to 69 jets. I also messed with the timing due to changing the distrubuter. Im currently sitting at 8* btdc and it runs smooth. I believe it was advanced before i removed it. I know timing can affect your temperature.

My question is, will advancing the timing increase temperature or decrease temps? Or is it the opposite? Or is the thermostat the problem

 

Hi Ollirapp,

Did your heating observation start at the same time as you changed the dizzy ?

I.E. Is your 'all in' timing and total timing the same as it was ?

 

And, is the vacuum advance timing the same ?

8* btdc sounds fine, but whatever gives the highest vacuum at idle will be ideal.

 

Neek. This is really my first carb vehicle. So bare with me. I think I set the timing with vacum advance connected but i really cant remember. Now I dont know what people mean when they say initial timing. But i will look it up. just from me understanding what i know is that intial timing is what i set it at. like 8* btdc.
Ive always had a spike in temperature since ive had it. But its usually at intial warm up and first drive of the day. I changed everything that you previously read. I changed the distributer for another issue of the truck not accelerating past idle. But previous to changing the dizzy, I f' ed with timing alot. So i dont know exactly where he had it when i bought it and the marks on the balancer were painted over.
Now the spike im wondering if it could be the tstat opening funny or getting stuck. but the higher temps seem to have started after i finished my troubleshooting of the last issue of not accelerating past idle and in result changed the dizzy.

 

Hi ollirapp,

What I meant by vacuum advance is the total amount of vacuum advance.
Different dizzies give different amounts. Some dizzies are adjustable and some are not.

That said, you can check if you have 'full manifold' or 'ported' advance at idle.

Initial timing is a.k.a. idle timing.

On your truck, idle timing (say 8*) + mechanical timing (say 28*) = total timing. Then one adds vacuum advance timing (say 16*) = 52*.
Hope that makes sense !!

''Too much'' advance (total and vacuum that is) would cause higher engine temps, but chances are you'd get 'pinging' with it.
I think that too little advance would also cause heating but I can't remember 100%.

Not sure about the spiking issue, so I'll keep quiet and not talk crap !!