Technical Sbc overheating issues possibly due to lake headers

No compression bubbles
Radiator has been taken out and checked at a radiator shop
Water pump has been checked

Going to check for an air pocket and engine richness tonight will get beck with more info / results

 

Leave the cap loose and see if it boils over. I'm betting that the temp ga. is reading incorrectly.
I spent a bunch of money chasing an over heating problem only to find out that the sending unit was wrong. It never boiled over but I was scared. A mechanics temp ga in the filler neck is cheap and you will have it for life. If it doesn't boil over you have no problem.

 

Were any other changes done over the winter that may be the problem?

Belt system changed ?
You said the pump was changed, Correct rotation pump for the belt system? Not the year model of the engine or the year model of the vehicle if it is a later model OT vehicle but correct for the belts that are on it now.?
Cooling system burped of all trapped air? It's not uncommon for a hot rod to have a special method of getting it's cooling system bled of all the air in it especially when a lot of them have a radiator that's top is lower than the high point of the engine's cooling system.

 

I know on motorcycles the lore is less restrictive exhaust causes you to run lean thus hot (as others have said) so I would pull a plug and see how it looks.

Ryland

 

Look in top of radiator for water returning from thermostat. I usually place a thermometer in top of radiator to check actual water temperature

 

So all those guys that show up at cruise nights and drag races that open there header caps are re adjusting there carbs? I call bull shit, but looking at the plugs seems as good of thing to look at as any

 

Dunno what coulda come over me...back to your regularly scheduled programming...

 

SO- Not being a smart ass to you-BUT..... You are using WE, and then,it's not my vehicle......
So do you own this/yours?,or someone else's? Hard to diagnose without time frames as what has/has not been done here....... And you don't know all the details.......^^^^^^^^^^. A simple pipe change will not do that which you describe.........hhhmmmm

 

Perform a leak down check to see if you have a gasket problem

 

If they are serious drag racers with a street/strip car that is driven to the track, then they should be. I have a friend with a '32 coupe that has been dyno'd with open and closed headers, and the optimum tune up is something like 2-4 jet sizes bigger with open headers. If he is racing uncapped, he changes the jets every time, then changes them back again to drive home.

The guys at the cruise night, not so much.

 

Non-causative correlation.

Clearly something else is wrong.

 

Poke it with a stick.

 

It must be global warming, you eliminated everything else...

 

Remove the thermostat, take the radiator cap off, look to see if there is water circulating. Go to Harbor Freight and purchase a cheap infared temperature gun to check the accuracy of your gauge. Your use of the word "instant" leads me to believe that either you are not getting coolant circulation or you gauge is junk.

 

Well, either they are running rich on the street with their mufflers and correct on the track open
OR
They are correct on the street and lean At the track with no mufflers.

It won't be idle screws to reach the correct air fuel ratio either, it will be a jet change.

There's no bullshit to it

 

Electric temp gauge wire got shorted during install? That would peg the gauge as soon as you start it up.

I'd verify with an infrared thermometer.

 

On a full on drag motor yeah I suppose it makes a big difference but on what is probably a stock motor doing what amounts to taking the baffles out of the headers should not/ will not do this. Take a cool running car and turn it into a dang volcano. There's something else wrong.

 

Here's the deal it's my fathers car I don't own it but i take pride and work on it like I do... I used we because I take a sense of ownership in the car as well... That being said being just out of college and strapped for cash I need to work as many hours as I can to provide for my projects so I can't be there every time he works on it and know all of the time frames and know every little thing he has done to the car.

Sorry rant over

 

Two things here that haven't been checked, water pump impeller (can rust away) and head gasket (do a compression check)

 

Put a new water pump on and did a compression check yesterday still nothing

 

I would follow the temp sensor lead. Is it mechanical? Is it electrical? If you "just changed headers", than perhaps the new primary runs too close to the sensor when the old primaries were farther away. The proximity of the primary might be causing the temp to read higher than reality. If your other headers weren't chrome and cooking off, there is no way that you can conclude that just changing the headers is changing anything with the engine.

Also when checking sensor location, check for header gasket leaks near the sensor. If it's pumping hot gasses right that the sensor, the result would be the same.

Pictures of headers, sensor locations, etc would be much more helpful in diagnosis.

 

The only time to re-jet when you open the headers is if you are scavenging properly. Most of the time when we see guys open them up the headers are not tuned properly and don't really scavenge that well.

Its like last year at the HAMB Drags when Will uncorked the headers on his big block. He said, "it won't make it any faster but it will be loud as hell" and he was right.

I would take a look at the jetting but lean mix won't make one overheat immediately. Most of the time lakes headers do not really scavenge that well they are more of a look at me and listen then make me go faster. no offense intended just being honest.

I have to ask this is the T stat housing above the radiator? Small block chevy motors are not known for trapping air but you do need to fill or burp your system at the highest point. Next is the pump actually pumping or just stirring the water. On a used/rebuilt pump it is common for the impeller to be worn to the point that it isn't really moving much water. When the T stat is open you should be able to look in the radiator and see a good solid flow of water, it should look like a river current and not a lazy river.

 

No offense taken... Look at me and listen (hope you brought your ear plugs) is what we are going for...

Like I said he put a new water pump on yesterday.... I think he ran out of time to start it last night... The t stat housing is much lower than the radiator

Attached is a pic... Most current one that I have... Not this is last summer before our issues occurred

 

nice looking ride - but, need clear view of both sides of motor - ideas/questions about location of gauge temp sensor sender need response - clarification of "instant" needed - just turn on key and temp gauge goes to high read?

 

I'm going to hang out with George for this one. It will be more fun to watch.

 

Sorry I will rephrase instant to five minutes at idle... Thought that was understood... Gauge and sender is working correctly has been checked with infrared gauge and it is right on...

 

Just for shits & giggles try ditching the thermostat and repeat the "idle for 5 minutes" test.
How's the fan doing? Has it been changed? What type is it?

 

Unless the OP is someone you know, that's pretty much the best policy on here. I been following it for over a year, lapsed a little, but from here on in, I'll stick to it. Hemi, if you see me posting on any more of this crap, feel free to just pm me a slap upside the head...
yall have fun now...

 

I can' see much in the photo in post 53 except that it appears that the top of the radiator is well above the highest point of the water jackets of the engine so that should pretty well eliminate the chances of an air pocket unless there is something hinky with the way the coolant flows back to the pump with that old box style tunnel ram.

Just thinking, most engines I have been around take at least a couple of minutes to warm up enough so the heads feel hot to the touch or at least excessively warm. That says that the engine may be extra lean, timing off or something went bonkers with the gauge.