Restoring Rusty

[Gregski]

Originally Posted by rich weyand

And here's why:
http://www.corvetteforum.com/forums/...tec-heads.html

Rich I followed the link and read the entire thread, and I got three different outcomes out if it, please correct me if I am wrong

1. One guy says I installed a bypass hose

2. Another guy says i have been running Vortec heads for years without a bypass hose

3. And yet someone else saying i drilled some 1/8th holes in the thermostat

So which is it? Whats the proper solution?

[rich weyand]

Originally Posted by Gregski

Rich I followed the link and read the entire thread, and I got three different outcomes out if it, please correct me if I am wrong

1. One guy says I installed a bypass hose

2. Another guy says i have been running Vortec heads for years without a bypass hose

3. And yet someone else saying i drilled some 1/8th holes in the thermostat

So which is it? Whats the proper solution?

OK, here's my take.

I think the guy with post #2 is the most correct.

Basically, if you have a system that is a loop, and you put a valve in it (in this case, the thermostat), then when the valve is closed, nothing circulates in the loop.

With me so far?

OK, so that's not a good thing. So the General built a second loop into the system, by installing a bypass that runs from the output of the water pump back to the engine, circulating coolant in that loop even if the valve is closed. So all the valve controls now is shutting off the radiator. But coolant still circulates, avoiding hot spots.

They didn't build this bypass into the Vortec heads for some reason (weight? the location already in the block inconvenient?), so you add it externally.

Now, lots of SBCs run pretty cold, like mine. Low compression, torquer cam, runs cold as a witch's heart. So I took out the always-on mechanical fan, and added an electrical fan which hardly ever runs except at sitting (no air flow from movement) on a hot day.

So a guy like me, with that setup, doesn't know about the bypass line, say, so he doesn't put it on. No problem, because his heater circuit sort of acts like a bypass, per the later posts in the thread.

But then some guy comes along who puts in the Vortec heads, and doesn't know about the bypass line, and cuts the heater out because he lives in Cali, and all of a sudden he is trying to diagnosis overheating issues.

BTW, another thread I found, one poster said the reason for needing circulation when the thermostat is closed is avoiding local hot spots, especially where the exhaust ports are adjacent to each other, to avoid (ta-da!) cracking the heads.

So that's my take.

[Gregski]

Originally Posted by rich weyand

OK, here's my take.

I think the guy with post #2 is the most correct.

Basically, if you have a system that is a loop, and you put a valve in it (in this case, the thermostat), then when the valve is closed, nothing circulates in the loop.

With me so far?

OK, so that's not a good thing. So the General built a second loop into the system, by installing a bypass that runs from the output of the water pump back to the engine, circulating coolant in that loop even if the valve is closed. So all the valve controls now is shutting off the radiator. But coolant still circulates, avoiding hot spots.

They didn't build this bypass into the Vortec heads for some reason (weight? the location already in the block inconvenient?), so you add it externally.

Now, lots of SBCs run pretty cold, like mine. Low compression, torquer cam, runs cold as a witch's heart. So I took out the always-on mechanical fan, and added an electrical fan which hardly ever runs except at sitting (no air flow from movement) on a hot day.

So a guy like me, with that setup, doesn't know about the bypass line, say, so he doesn't put it on. No problem, because his heater circuit sort of acts like a bypass, per the later posts in the thread.

But then some guy comes along who puts in the Vortec heads, and doesn't know about the bypass line, and cuts the heater out because he lives in Cali, and all of a sudden he is trying to diagnosis overheating issues.

BTW, another thread I found, one poster said the reason for needing circulation when the thermostat is closed is avoiding local hot spots, especially where the exhaust ports are adjacent to each other, to avoid (ta-da!) cracking the heads.

So that's my take.

Thanks for that explanation, I got confused because I read the #2 guy wrong, I took it as No Bypass Hose and No Heater Core, but that's not what he is saying. He is saying all things stock ie run the Heater Core like a [ahem] normal person would, ha ha and then you don't need no bypass hose. Which makes sense, cause [duh] essentially you are running a long bypass hose that just happens to have a second radiator in it, called the heater core.

OK, now we are on the same page, (of the same book) sorry, sometimes I am just a little slow to get things.

[Gregski]

Originally Posted by rich weyand

...So the General built a second loop into the system,...

OK bud, this had me crackin' up and I must give credit where the credit is due, I have not heard that expression before "the General" I like it, I can dig it, I must use it

[Gregski]

Originally Posted by rich weyand

... Now, lots of SBCs run pretty cold, like mine. Low compression, torquer cam, runs cold as a witch's heart...

Rich I honestly did not believe that until the gauge without the thermostat read 150* F at idle while parked and dropped to 148* F while driving with the wind in its grille

Give this man a hand guys, he know what he talk about!

so I took out the thermostat and had to find out how hot or cool the engine runs without one, I mean we are troubleshooting here folks, we are learning, we are gathering information and our data must need be complete so that we can make an educated wild @ss guess at a solution, right?