Technical Overheating SBC (time to expose my ignorance)

The car was running great before all this happened. OK- took the driver side head off of my 327, as my dad was convinced it had a cracked piston (he is in the middle stage of dementia, and there was no refusing him). We get in there, find no issues. Put a new head gasket on from the stash, buttoned it up, and went down the road, about a seven hour trip. The car has many long trips on it, never a hic-up. This was in April-May, going to south Texas. The car (56 Nomad) wanted to run hot. I rolled down the windows, ran the heater (fun), and kept the heat at 75-90% hot. It would get hotter when going thru towns, go down some (not to normal) when I got up to speed. Car has a newer aluminum radiator, electric fan. No reason to suspect this stuff, it has always worked. I have put a new thermostat in it, checked the timing, (4-6 degrees btdc), the vacuum advance was hooked up to the pass. side of the Edelbrock carb, I tried the other side, no change. Distributor is HEI. The car gets hot pretty fast in town, no more that 5-10 minutes. Unless I put an incorrect head gasket on or installed it incorrectly, I have no idea what has happened.
What do you all think? I want to go with a mechanical fan, but that's not the issue right now. Haven't checked the lower radiator hose. Thanks for your help, HAMB.

 

Is there any crap in the system, like rust flakes, etc? that could be plugging the radiator

you checked the vacuum advance is working properly?

 

Only thing I can think of is the vacuum advance isn't working correctly, keeping the ignition retarded. Might verify it is working as it should.

Squirrel is quick.....

 

also might verify the mechanical advance is working, if it's an old GM HEI, they do have problems with the advance mechanism wearing out. This was a problem with them in the 1970s.

 

There shouldn't have been a need to, but did you disconnect electric fan and reconnect it and it's running backwards now?

 

Did all this start after you replaced the head gasket & the radiator? HRP

 

Maybe needs a burp (air lock)

 

Any bubbles in the radiator when run with cap off? Old hose collapsing? Losing any water or moisture out the exhaust?

 

I was also wondering if there was air in the system not letting fluid always get to the thermostat especially when you say it heats up quick in town. I have had that one bite me a couple times so now drill an 1/8" or so hole in all my thermostats if they don't have a bleeder in them. May be a long shot though considering sounds like you have driven it quite a bit since pulling the head.

 

What is 75 - 90% hot?

 

only thing changed was the head gasket soooo.......
I would look there if "the burp" don't help.
Compare the new gasket (holes) with the old gasket!??
6sally6

 

Heat up at slow speed air flow, you would think the radiator or slow timing would have more effect at speed. Also look at post #5

 

I will check the advance, see if it's working. Rad was replaced several years ago, shouldn't be an issue. Fan runs as it should- ( i thought about that, checked it). 75-90% hot is going by the original gauge in the dash. It used to run right in the middle. No bubbles in the radiator, I have wondered about a "burp", will drill the hole in the t.stat. Cooling system is clean, no dirty or rusty water (that doesn't mean there's not a chunk of crap stuck somewhere). The only things removed were the distributor and the head/intake. I don't still have the head gasket I took off, can they put on backward/upside down? Yes, all this started after I replaced the head gasket. Car was as dependable as a rock until then.

 

It's not a Ford, you can't put the gasket backwards.

Sent from my Trimline

 

I would first verify the gauge. Sender was disturbed when manifold and head r an r’d. Pick up a cheap laser thermometer and check it out. One of the better harbor freight buys.

 

Agreed. Probably a stupid question, but it sounds like it's maybe just low on water.

 

Yep, you can put a Ford head gasket on backwards...don't ask

 

Add verify the actual temp with the infrared temp gun first.

 

Explain HOT !!

 

Hot=coolant gushing from the overflow. The car got HOT.

 

Yep, sounds actually hot...not just by the gauge.

 

Depending on temp gauge reading if it burps out water it could be finding its own level , you can put too much water in rad when it expands it has to go somewhere

 

Given that the problem started after you changed the head gasket and you have verified that the motor is actually running hot, I think I would start with pulling it down and replacing the head gasket again. It may not be able o be put on backwards, but it can be put on upside down (the head side of the gasket against the block). Short of replacing the head gasket, the only other possible issue I can see would have to be with the dist, maybe your loosing ground, or the timing was not put in the same place it was before. I suppose it could also be a defective intake gasket causing a vacuum leak making a cylinder run lean, might be able to see that by pulling the plugs.
With the poor quality of replacement parts these days, it is possible the new head gasket may have had a cooling hole out of place, or not even punched out. Gene

 

Why did your father believe you had a cracked piston? What was the issue that prompted him to think that?

 

Re-read the first post REALLY close. Then you might understand...

 

The alternator was making a little noise,he can't hear all that good anymore, and dementia is a bitch.

 

Well, I tried the 1/8 inch hole in the thermostat, thought it was helping, but no. 85 degrees, still finally got hot. I think it took longer, but still the same outcome. Looks like it gets a new head gasket. Here's a pic just for fun. Thanks for your help and advice.

 

The last time I had something similar happen I changed the springs and weights for the advance inside of the hei and it fixed it. Was really frustrating trying to figure it out. @porknbeaner Helped me fix it so he’s probably who figured it out lol

 

Here's hoping it's just a goofy gasket or an easy fix. Shame not to be driving such a nice car.

 

Tim has same ideas I was going to suggest. Four to six degrees initial advance doesn't sound like enough.

Usually 34 degrees total advance should be reached by 3000 rpm, with vac advance disconnected and plugged.

Phil