The Stovebolt Site Forums The Shop Area Engine Shop Overheating&running bad

I have a 58gmc 270zenith carburetor.set the timing by the flywheel mark.Rotor pointed at #1 wire.points were open.carb set at 1turn needle valve,2.5 turns on main screw.After warmed up;took it around the block,no problem.Went to store(5min trip)took 35mins.Overheated,stalled 3 times&barely was able to get it back home.WHAT"S going on ?Guess Ill replace the thermostat(Which I did4months back).Why would it seem to do okay at idle but then no power?Couldnt give any gas whatso ever.
Danny

Check the timing with a timing light, or by ear if that works for you.
One symptom of overly advanced timing is overheating, not sure that is any or all of your problem, but it is worth looking at.

Also, the number of turns for the carb adjustments are only starting points, you need to tune by ear and trial and error from there.

Grigg

dtwbcs,

I would do a compression check on it after it's real warm. Some overheating could be associated with timing but yours almost sounds like a blown head gasket.

A functioning radiator should have the capacity to cool it down even after getting hot, could yours be plugged or dirty.

When a engine get real hot, all kinds of things start to happen. Marginal ignitions fall apart, fuel systems start to boil and act strange and things just get weird. If you are using coolant, this could support a blown head gasket or cracked head theory.

Stuart

Set the timing manually yesterday.Had it idling fairly smooth.How would you check a clogged radiator?send it to the shop?If it has a blown gasket,would the oil look milky?will the engine actup only after warmedup?I noticed the idle seemed to have dropped.was "popping"out the exhaust pipe while driving down the road.How can I prevent the distributor from"walking"after I set the timing?

Did you drill a hole in the thermostat to let air escape when you filled it with coolant?

First thought I had was air in the cooling system, but after you said "popping" out the exhaust I would lean more towards timing or valves. Did you do a compression test? Could be a burned or bent valve?

how old is the radiator ? could it be cloged or have poor airflow ? i had that happen to me once. if it idles fine and only heats up when the engine is loaded that may be the cause. if you can look inside the radiator via the filler cap check to see if the flues you can see are clogged. if thats the case have it rodded out or replace it.

Consider inspecting the manifold hotbox. If it is burnt thru , there will be issues similar to what you describe.

I took the thermostat out&buttened it back up.reset timing using a light.was looking inside of the radiator for water circulation.-noticed tiny bubbles about half the size of a BB every so often.idled the truck for a while before backing into garage.
Danny

Put a new thermostat in&It seems to be doing fine.Guessing the thermostat was stuck-closed