overheating

[53burb]

I was just thinking about this. I have a timing light. When I first converted over to an HEI dizzy, I timed it to 8 degrees BTDC. When I reinstalled it the other day, I couldn't find the timing mark with the light. I marked the indention with white chalk and still couldn't find it. I looked again today and still couldn't see it. Both times the vacuum cannister has been unplugged. The dizzy was new about a year ago. Is it possible that the dizzy advance mechanism is stuck?? This would lead it to getting hot correct???

[CHEVIBUBBA]

it is possible.but, it would probably be hard to start.you should inspect the internals of the dizzy anyway so...
you NEED to find the timing mark.does it have a new harmonic damper?
if not, the outer ring could have slipped.
one way to find it is to have the engine running with the timing light on it.
turn the dizzy one direction slowlyuntil it almost dies.watch the damper as you turn the dizzy.if you don't see the mark, turn the dizzy the other way.
it should show up one way or the other.
if not the outer ring has slipped or the timing is way off.the dizzy may be in a tooth or more off.
btw;if you pull the vacuum canister towards the front you are advancing the timing.pushing it towards the back retards timing.
it sounds like it could be way retarded.
one clue to it being retarded is you'll have the idle screw on the carb screwed way in.
did the t-stat close pretty quickly when you had it out hot?
if it stays open it can allow rad juice to flow too fast thru the rad for cooling.
spark plugs=no.
why did you"reinstall the dizzy the other day"?
once again i ask;has the engine done this since instal?

[CHEVIBUBBA]

just reread a post.you say you had the same problem on the engine before this one.
sounds like a used component is faulty.
you swapped rads but, no guaranties there.
new water pump twice.probably ok.
are the hoses used/ok?
have you physically verified it is overheating?
get a thermometer & when it indicates hot check it in the filler neck,(be carefull!!!)
or at least in the fins.
have you verified airflow thru the rad?
a good test is with the engine idling the fan should hold a full pack of smokes against the fins without it falling.or damn near.

have you verified water flow out of the t-stat housing/thru the rad?

[53burb]

The top hose is new. They gave me the wrong bottom one, so it is still the old one. It stalls when it is hot and I can hear the water boiling. I assume the airflow is ok. There is no a/c condensor. If I put my hand between the fan and waterpump, I can feel the fan pushing the hot air out. Maybe I should put the old flexfan back on to see if there is a difference. I had the cap off earlier with the engine idling and the coolant appeared to be flowing.
The balancer is new. If the dizzy is off by a tooth or more, would it still start?? I turned the dizzy counterclockwise to adjust it. The thermostat closed after a minute. I reinstalled the dizzy after I replaced the engine. This engine has done this since I installed it. It was doing this also on the old engine about a week or two before I pulled it. I thought it was the thermostat, and I have replaced that. Shortly thereafter, I blew the head gasket and replaced the engine.

[Idaho68]

I dont know if you have checked his or not, but is it possible you have an air bubble in the cooling system? I had an old Pontiac that would get a bubble in the heater core and it would act similarly to your description. If I didnt fill the old beast with coolant with the nose at least a couple feet in the air it would trap air in the core, might try pointing the nose up a hill so the cap is higher than the heater core, and pull the cap, then rock the truck a bit, if the coolant in the radiator drops, there was a bubble, if not...well then I am bamfoozled meself

[53burb]

I thought maybe I have an air bubble, but the heater core is bypassed. I thought I read before to drill a hole or two in the thermostat to alleviate this too, but the thermostat is out right now, and I still have the same problem.If nothing else comes up, I will pull the dizzy tomorrow, make sure it is ok under the cap, and reinstall it.

[Zeke]

Might want to check the bottom radiator hose, some have springs in them to keep them from collapsing some don't. I have seen bottom hoses separate and the internal lining collapes shutting of the water flow causing it to over heat. Just a tought since you said it is still the old one.

[53burb]

I will check it again tomorrow, probably get the correct one tomorrow or Sunday....

[CHEVIBUBBA]

good luck

[86SILVERADO]

Sounds to me like you have the timing way to advanced. Counterclockwise on the dist. will advance the timing. Does it drag and hiccup when trying to start it initially? If you are stalling out from overheating you could be locking up the motor. I hate to say it but it sounds to me like you drove the thing a little too long with improper timing. You may have blown another head gasket or are close to it.

[53burb]

OK I feel like a freakin' idiot. I replaced the thermostat. Pulled the dizzy and checked that it was ok. It was. Popped it back in. Timed it. I did see the mark this time. It was way, way advanced. The timing mark was at about the 11 or 12 oclock position before I set it correctly. I thought I had seen it there yesterday, but I thought it was the sunlight, I didn't think I could be that far off. Anyways, when I set it, I had the rotor facing straight in the middle, when I actually should've had it set towards the drivers side. The dizzy is turned way more than I would like to compensate for this. I will probably pull the dizzy tomorrow or next weekend to fix this.
86 Silverado-It did use to drag when I cranked it up. I assume this is related to it being hot. I thought it may be related to the charging system. Any longterm affects?? The head gasket isn't blown. Am I just squeeking by?? Or am I OK??
THANY YOU everybody for you input. It is greatly appreciated.
Chris

[4x4Poet]

In case the dizzy ain't the prob, measure the temp of the rad's core at various places to check for clogged tubes. And did you ever check if the bottom rad hose has its anti-collapse spring inside?

[53burb]

I am going to be replacing the lower tube later today or tomorrow...The dizzy was too far advanced, that was the problem...

[86SILVERADO]

The drag you feel is because the timing is too advanced. The spark comes too soon as the piston is climbing in the bore and the mixture being fired too soon actually pushes the piston back down before it has reached top dead center which gives you that feeling of the motor struggling to crank. It is very similar to when the solenoid overheats or the batery is low but it is really due to overadvanced timing. The real prob is the timing being too advanced this is causing your overheating. It also causes a whole host of other problems especially if you run cheap gas. First get the rotor pointing to #1 tower (which you want to be the second one clockwise from the coil contacts on the cap for proper positioning of the dist.) when the mark on the balancer is at the 8 before top dead center on the timing tab. This is really pretty much where you will want it. The only thing you really need to check with the timing light is your vacuum advance. while the motor is running with the vacuum advance plugged into a full manifold vacuum port the timing mark should be at about the twelve o'clock position on the balancer (you verify this w/the timing light). This is with the engine warm and idling at about 7-800 or so. One thing I have found is sometimes the weights get stuck under the rotor in the advanced position and this can throw the timing off keeping it too advanced at idle if the weights get stuck and can't retract. I usually put two small washers under the rotor to raise it slightly and keep the weights from binding. I am sure this is not a problem with all rotors but I have had some aftermarket ones with this problem. The other thing you need to check if you haven't already is that the dist shaft is not gummed up and is able to advance at all. Take off the rotor and hold the tab that the rotor mounts to. and twist the upper plate that the weights mount to and make sure it twists freely and snaps back freely as well.

[Boog]

Ditto on the mention of checking the dist shafts free movement. I had one get to running really lousy and it turned out to be the shaft gummed up with the centrifugal advance in the advanced position. Dismantled the dist and cleaned it good and put back together. All was fine afterward.