Restoring Rusty

[rich weyand]

Follow-up:

The location of your up-and-over-and-down hose in the pic on p 154 of this thread is correct. Lots of nice pics of different pretty ways to do it are here:
https://www.google.com/search?q=vort...h2CLUQ_AUIBygC

You need to do it, because you do NOT want to be circulating coolant through your heater in the summer. I put a valve on mine so I could shut it off, because there is minimum amount of heat you get from the heater even when it is shut off. And when it gets hot here, any amount of heat is too much.

[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.

[rich weyand]

One other thing you could do. Run the bypass hose with a selector switch in it that can select the heater core OR the bypass. So one selector valve and a T. Then you can have the heater core for the winter, and bypass it in the summer. The one thing you can't do is just shut it off.

What you need is a 1/2" NPT 3-way valve. Search that on Amazon or google. Looks like 30 bucks for a competent one. Here's an example: Industrial Grade 1PZA1 Three Way Ball Valve, 1/2...
Basically it hooks up between the heater hoses like an H-pipe in the exhaust, with the valve in-line on the smaller hose, and a hose across to a T in the other hose.

[Valarius_Starchaser]

Originally Posted by rich weyand

One other thing you could do. Run the bypass hose with a selector switch in it that can select the heater core OR the bypass. So one selector valve and a T. Then you can have the heater core for the winter, and bypass it in the summer. The one thing you can't do is just shut it off.

What you need is a 1/2" NPT 3-way valve. Search that on Amazon or google. Looks like 30 bucks for a competent one. Here's an example: Industrial Grade 1PZA1 Three Way Ball Valve, 1/2 In NPT, Brass: Amazon.com: Industrial & Scientific

We get guys doing that up here and they are also the guys coming in to get their heater core flushed every winter because the lack of flow forms a sludge and makes it work poorly just my .02

[rich weyand]

Originally Posted by Valarius_Starchaser

We get guys doing that up here and they are also the guys coming in to get their heater core flushed every winter because the lack of flow forms a sludge and makes it work poorly just my .02

Yeah, you gotta turn it on and let it flow a bit once a month or so to keep that from happening, just like the guys with the garage queens should start their vehicle and let it run for a bit once a month during the winter.

[rich weyand]

One more thing. You can get those 3-way valves with electric actuators, so you could hook it up to run through the heater core when you selected Heat, and otherwise switch to bypass.

[Jake Wade]

Try bumping your initial timing up to 14º-16º. You have a larger camshaft now and this is a good number.

Your vacuum reading at idle most likely will not be over 16-17 with that camshaft, and that's well tuned.

[Gregski]

Originally Posted by enaberif

1) Quit running water! Your truck needs either antifreeze or something like "water wetter" (http://www.redlineoil.com/Products.aspx?pcid=10) if you want to keep using water.

Last night I drained the radiator and added properly mixed Antifreeze (50 water 50 coolant) FYI I did not use distilled water as I read that water is robbed of all its nutrients and I did not use drinking bottled water since the engine block is 40 years old and I did not hot tank it to clean it, as well as the radiator is all rusted up inside as well, had this been a brand new block and new rad I would have used drinking water, and the wife and kids would have had to drink tap water, ha ha

I feel like I need to explain my thinking process for using water. I was using water because it is much easier to clean off of the engine block if you have to remove the thermostat water outlet half a dozen times, as well as the garage floor. Also it is my understanding that Antifreeze lowers the freezing point of water as well as raises the boiling point, so I do not expect much change in my condition by running the green stuff, but we shall see. And finally I know many car racers that say they have to run straight water at the race truck so they don't spill antifreeze on the track, I know that is a fact, so if it is good enough to cool their engines which they push way harder (upwards of 100 MPH) than I am pushing Rusty (45 MPH, lol) water should cool my truck just dandily provided everything is in order (gaskets, bypass hoses, fan, radiator, etc.)

again Not arguing, just sayin'

[Gregski]

ok, so lets sum up the situation code name WATERGATE (you like that? I came up with it all by myself)

In the beginning with no bypass hose we were running hot as so...

[Gregski]

then we added the bypass hose from the intake manifold to the water pump, or water pump to intake manifold which ever way you swing

... and that took us out of red line aka out of critical but still East of the middle on the gauge

[Gregski]

next we added Antifreeze Coolant into the system, so now we are running 50/50 with water mix, and that did nothing, the reading is exactly precisely the same [pause to scratch head]

[enaberif]

Without knowing what those ticks reference in regards to numbers who knows what you are reading.

[Gregski]

Originally Posted by chevybuldr

... Over heat issue might be an air pocket in the cooling system. You need to put the truck on the driveway, make the radiator higher point then the back of the block. Just because water comes to the top of the intake doesn't mean there is not a pocket.

I like that idea, and so I tried it, ended up adding a tiny bit of coolant to the radiator, and there was no change in how hot it runs after, still runs hot

maybe you all can share pics of your happy water temp needles with us, so I have something to compare mine to, please

[Gregski]

Originally Posted by enaberif

Without knowing what those ticks reference in regards to numbers who knows what you are reading.

Now on this we can agree 1,000%, I hate gauges without numbers, do you know what you call a ruler without numbers? a stick, do you know what you call a gauge without numbers? NOT A STINKIN' GAUGE, that's what!!! ha ha

[SkinnyG]

I have a 195° thermostat in my truck, and the operating temp is a tick below the first line (1/4 of the gauge).

I have an electric fan, which is switched on at 212°, and off at 192°, and the needle never passes the first line.

My truck is a '77, with original gauge and presumably sender.

[Gregski]

Originally Posted by SkinnyG

I have a 195° thermostat in my truck, and the operating temp is a tick below the first line (1/4 of the gauge).

I have an electric fan, which is switched on at 212°, and off at 192°, and the needle never passes the first line.

My truck is a '77, with original gauge and presumably sender.

thank you so much, excellent detail, I hope to hear from conventional fan folks as well

[Gregski]

... we now step away from WATERGATE momentarily and join Timing Adjustment already in progress...

[Gregski]

Originally Posted by Jake Wade

Try bumping your initial timing up to 14º-16º. You have a larger camshaft now and this is a good number.

Your vacuum reading at idle most likely will not be over 16-17 with that camshaft, and that's well tuned.

bumped the initial timing to 16* and with manifold vacuum hooked up to the canister on the distributor the engine is set to idle at 850 RPM and it pulls a perfect (steady) 20 inches of Mercury (that is as close to perfect as you can get) I honestly don't see my camshaft as much of a performance cam, its moderate at best

I don't think this will impact my engine running hot (notice I did not call it overheating) but only a test drive or two will tell, and for that we will have to wait until tomorrow

[rich weyand]

On temperature, I have an original guage, and a reproduction sender to match the original. Note: not a substitution gauge, a reproduction gauge with the same resistance curve as the original. American Autowire did it for the Corvette restorers, whose gauges read in degrees. It drove them nuts not to have them read right. It turns out they use the same resistance sender as squares up through (I think) 79.

The full details on senders are in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=630399

My gauge now reads just shy of straight up when everything is operating normally.

[rich weyand]

Originally Posted by Gregski

bumped the initial timing to 16* and with manifold vacuum hooked up to the canister on the distributor the engine is set to idle at 850 RPM and it pulls a perfect (steady) 20 inches of Mercury (that is as close to perfect as you can get) I honestly don't see my camshaft as much of a performance cam, its moderate at best

I don't think this will impact my engine running hot (notice I did not call it overheating) but only a test drive or two will tell, and for that we will have to wait until tomorrow

OK, so you're getting steady vacuum and idle now with the vacuum can hooked up. Good.

I went looking around, because I thought stick shift idle was supposed to be lower than auto trans idle, but it looks like I misrecalled. You look good to go right there.

[Gregski]

Originally Posted by rich weyand

... My gauge now reads just shy of straight up when everything is operating normally.

Thank you very much Rich, so we are aiming at West of middle.

I pulled the trigger on this gorgeous Summit brand digital water temp gauge SUM-G2984-1G for $35 and its accompanying sender SUM-G2984-1S for an additional $10, and knowing Summit they may arrive today.

[rich weyand]

Originally Posted by Gregski

Thank you very much Rich, so we are aiming at West of middle.

If your sender matches your gauge, yes. The problem is that a lot of senders were replaced with book substitutes after 1513321 was obsoleted, and the book substitutes don't have the same resistance curve. Getting the true reproduction (see pointer in thread I posted above) will guarantee the gauge reads correctly.

[Gregski]

so took the truck for a standard 30 minute test drives now that I think I have the timing dialed in, gentlemen the truck sounds good to me, it sounds like a fine tuned Swiss Tractor, lol, no seriously it do sound good, but it still ranned hot

when I got home I felt the radiator cap and it didn't feel too hot, so I did what you aint supposed to do, unscrewed it, then I shoeved the wives favorite turkey thermometer in it, and it read 164* F

now I know and you know that I know that, that's in the radiator and not in the cylinder head or not in the intake I get it, but heck we got some sort of a reference digit, know what I mean bro

[Gregski]

Originally Posted by enaberif

Without knowing what those ticks reference in regards to numbers who knows what you are reading.

Gentlemen sometimes you just gotta MacGyver the snot out of something (honk if you be old enuff to know who MacGyver useta be) ha ha

so we used our digital thermometer as a baseline control, we decided to boil some hot water and we stuck the 1974 water temp sending unit in the pot as well, we were making Vortec Soup, both were suspended in the water and not touching the bottom hot plate, the sending unit was connected to the gauge with its green wire and its housing grounded to the battery negative terminal to ensure proper and reliable ground (ignore the color red wire, an aligator clip is an aligator clip)

brilliant if you ask me

so with the truck off but the key in the on position (not start, just on) as the water begun boiling the digital control gauge started climbing, our truck gauge didn't for a while, it was a bit slower to react (a bit discouraging at first, but then...) then it started to move

I recorded the first notch as 190(ish)* F

I recorded the middle notch as 210(ish)* F

since water boils at around 212 that was as hot as we could get and the wife caught me using her pot so I couldn't add no Antifreeze to it, ha ha

but we might have some reference digits now

[daddyjeep]

Very nice test here. Don't trust anything. It kinda reminds me of my engineer days.