Technical SBC 350 - How hot is too hot?

We are talking about a small block chevy and filling the radiator, are we not? GM made millions of them and I'll bet most had some mixture of water and anti-freeze and they all ran. Fill it up and if it does not boil over you are good to go. I am no longer watching this thread, it sucked the last little bit of brains I had out of me. 50/50 or 40/60 who f*****g cares!!!!

 

https://www.google.com/search?hl=en&site=imghp&tbm=isch&q=skirts

 

He's OVER thinking it again. It was nice to see it out of the garage.
(You beat me Jim!!) My bet is next thread: fender skirts or not?

 

I have never understood why a person would buy 50-50 pre-mix antifreeze. But I buy Bottled drinking water. Around corn field Indiana here the stores charge the same for full strengh anti-freeze as 50-5o wtf is up with that are people just stupid or that lazy??? Don in cold and snow covered Indiana

 

END OF THREAD.

Thanks all, but I hope no one else replies. I always feel compelled to reply and then the thread keeps growing.

I'm filling it back up with something. If the motor overheats I did something wrong. Looking forward to talking about skirts and 8 pages of it.

 

I know you wanted to close this, Dan, but one quick note on IR thermometers. They are designed to work on "black" surfaces. They're not as accurate on bare metal, polished metal, or other colors. You usually have to read the really fine print on the instructions or go to the Manufactures website to glean that little tidbit of information.

Ps. You don't need to reply to this one! ;-)

 

Keep it Rollin, never give up!

 

Hint:

Make it a poll

 

You got enough oil in it?

When you're down a little, or a lot, friction raises the temperatures.

Just another thought.

 

Thanks. Oil is at the proper level and it was brand spanking new oil with no miles the time I had driven it and it was running near 220 in traffic.

 

It's me again.. yea I know I said I was done but I felt obliged to report back.

I drove it today after all the work I did and it is running 185 on the highway and 195 to 197 on stop and go traffic. It never got to 200 and never went above it. Granted the weather was in the upper 60s today which is a little cooler than last time, I think it is running quite cooler right now. The temp sensor was kept at the cylinder head.

I basically filled the drained radiator back up with Brita filtered water and I added 1 bottle of water wetter. I put the Mr. Gasket 180 deg thermostat in.

I will use my hydramometer tomorrow morning to measure the coolant properties and make sure it's sufficient for the coldest temps San Diego may see.

Here are some photos from my drive to a quiet North County San Diego beach town to meet a pretty strawberry blonde girl. I wish I would have made her pose with it but she liked the car, hope that helps my cause next time

Thanks to all that helped with advice.

 

Some times you over think things. A cooling system is pretty simple. You have a radiator that dissipates heat from the coolant, the water pump circulates coolant thru the system, the fan provides airflow when tje car isn't moving and the thermostat that opens when coolant gets to the temperature it is rated at and closes at the same temperature..... When it opens the hot coolant rushes past and when the cooler coolant makes its way from the radiator it closes. This does two things, it allows the coolant to absorb heat from the motor and allows coolant in the radiator to cool.

That said... All you need to do is provide the balancing act between absorbing and dissipating heat.

If it runs fine driving around and the temp climbs sitting at an idle.... You need more airflow via the fan and shroud.

If it runs hotter driving either the radiator is too small or is restricted .

Higher temp thermostats are used in the newer cars to reduce NOX emissions.... Not make the convertors work better. Engines also produce more power at higher temps along with a leaner mixture... Which also reduces NOX.

Yes.... The temp gauge will read cooler placed in the intake manifold. The temp sender in the head is sitting between combustion chambers... Where the most heat is. If it is running at the temps you are at... You are in good shape.

 

I can't really add anything to what's already been said. It's fun trying to fix someone else's attempt at building a car is't it? In the second to last pic you posted, # 1 exhaust valve retainer/spring look awfully "black" compared to the others; there could be something going on there contributing to your overheating issues. Then again, it may be nothing. I would however toss the "flex fan" in favor of a stock style fan, and with the radiator to water pump distance, you may be able to use a factory clutch fan. A shroud around the fan may help, but our 51 Bus Coupe with a 350 and an aluminum Champion radiator, without a shroud, cools the engine just fine. Keep at it, you'll get the car in shape. I am Butch/56sedandelivery.

 

Gotts agree with Butch, and I said it in a previous post. Get rid of the flex fan and get a factory hi-perf fan, from an air conditioned car, 5 or 6 blade. Hot at low speed or idle is airflow problem.
If it doesn't work, add a shroud.

 

Thanks for that catch. I had taken that picture as I was getting the cylinder head out. Ineed the #1 exhaust valve was toast and I had taken the cylinder head to a machine shop where it was fixed. It is slightly darker in color than the rest with the parts he changed. He didn't replace all of them and I trust they knew what they were doing.

Since then the exhaust idle has sounded so much more consistent.

 

Thanks, should I maybe wait until hotter months to see how it behaves? Right now as I said, on the highway its at 185 ish, and in traffic it's at 195 to 197 tops. That's with my sensor on the cylinder head. Maybe that is just fine for now without a shroud and changing the fan? I also had remember reading the flex fans are designed to change pitch under higher RPM so it doesn't fight the incoming airflow?

 

drive and enjoy!

 

I agree with you are over thinking this. The coolant was changed which would have improved its efficiency to remove heat which would raise the temperature of the coolant. The coolant is doing its job.. At 212F at 7 psi you are still a safe distance way from boiling over. Changing to electric fan is treating the symptoms vs attacking the problem. Adding a fan shroud & improving the existing fan efficiency is an inexpensive way to move more air through the rad as it is not losing air off the end of the fan blades. The air is contained & directed. An unenclosed fan is inefficient. The fan shroud will help the radiator shed more heat.

Vicky31's charts clearly show that the boiling temperature of the afreeze fluid raises the temperature to boil & flash to steam. Steam will instantly cause the system to over pressure & blow. The point is that a 50/50 afreeze & water reduces the ability to boil. The benefits of 50/50 antifreeze mix far out way using water. I live in Canada where it can swing from -45F to 100F where antifreeze protects the engine from freezing and corrosion. The less corrosion in your engine the more efficient it will work. Layers of rust will break down the engines ability to transfer heat out of the cylinders and foul up the cooling including the rad. I am a fan of 50/50 glycol with distilled water as I have never lost a rad to corrosion and some of my vehicles were 20yrs old and they salt the hell out of our roads in the winter. Distilled or demineralized water is free of all chemicals like chlorides that will attack the radiator.

I built a large building for our company where the incoming air was heated with glycol through heat exchangers. The boiler side of the glycol water heater was water treated with system protection chemicals to save money. The heated glycol warmed the incoming air while the building was heated internally with treated water. The controls on the glycol side worked without any issues. If the water side did not receive its monthly chemical treatment then control valves started to stick and quit working. The architects argued that using water treatment was to lower operating costs. IMHO The cost of the labour for monthly testing & the chemical cost of treating the water side plus the associated maintenance headaches were no savings. The only money saved was the initial fill of afreeze.
I built a second build of equal size with a similar heating system but had the whole system run with glycol antifreeze. The buildings afreeze was tested to verify its condition & it lasts for a longer time than a car engine. We had no problems with the equipment & it was 10 years old when I retired.

Antifreeze in a mechanical cooling system is superior to water. The question is what are the right ratios for your climate that still maintains maximum corrosion control.

 

I don't think I've weighed in on this one yet, but I'm also not a fan (get it!) of flex fans. Although your not stressing it as much as I was, I've had one blow apart at full throttle and send two blades through the hood, and one through the fender! I believe the belt came off first and caused this, but why the blades would fail before shredding the belt is still a mystery to me. As far as I know, no OEM ever used a flex fan, and that ought to tell you something! As engine speed increases, the flex fan blades flatten out to free up power required to turn the fan, not reduce air resistance. In fact, as they flatten out, they take up more surface area behind the radiator, effectively blocking more airflow. I prefer a good Haden or OEM fan clutch with a 5or 7 blade fan, given the room to run one.

Posted using the Full Custom H.A.M.B. App!

 

Thanks, the only remaining thing I have left is to just measure the coolant with the hydrometer. I know a shroud and non flex fan will help, but it's on the list. For now I'm driving again without worrying about the cooling system and am considering this a done deal for now.

 

that tells me you didn't work on many 1970s Mopars....

 

I think you are golden & can run safe.

I have worked a lot with industrial boilers, steam & condensate systems in a maintenance & design roles for a large industry. I have seen the benefits of using chemicals for corrosion control & cleanliness to keep the equipment operating efficiently & reliably. Some of our company's sister sites did a poor job of water treating their boilers so their boilers scaled badly, had to be acid washed annually and they cut tube samples to check for scale & pitting. Every acid wash reduced the tube thickness a few thousand and shortened their life. Our boilers & steam systems ran shiny clean because of careful boiler feed water treatment. We never acid washed unless it was forced on us occasionally from the corporate level. It was pointless but we liked to keep our jobs.

I built the first building with the combination of water & 50/50 afreeze which we had to babysit the heating system. I over ruled the architects and mechanical designers to have the second system run entirely on 50/50 which made the second building operate with no issues. I think the antifreeze kept all the dozens of control valves running happy. On the water heating system when the valves started sticking it was obvious that the water treatment had slipped. I have also seen the benefits of good afreeze in 40 years of driving. I know it will raise some fur but running straight water is less than ideal. If a system can be made to run clean to be efficient & reliable then that system will give a long happy life.

 

Nope, my dad and stepdad were both died in the wool Chevy guys, and I didn't stop drinking the koolaid till the 90's. Now I've gotta go dig up a picture if my '69 Superbee and see what fan it had on it!

 

Just did a quick check after the car has sat since Saturday. The reading with the hydrometer is just to the right of freezing point text. Hmmm, 15 deg F if that thing is really accurate at all. With pure water the indicator is just to the left of the freezing point text.

Like I said before, I filled the radiator back up with Brita filtered water and a full bottle of water wetter. What was left in the block that wasn't drained was likely 50/50.

I don't expect to keep the car outside at night ever, I can't imagine it getting below 32 deg F in San Diego, though it can. It's kept in a little garage with poor insulation.

I like the temps the motor is running at. I should have refilled with what I drained after changing the thermostat just to see how much of a difference that made, and then tried filtered water and water wetter to see what additional change that would have made. Owell.

I could maybe drain 1/4 of the radiator and fill with AF concentrate for peace of mind (more corrosion resistance slightly more buffer for freezing temps should the car end up in someone else's hands in the near future), but I said I was closing this issue up and moving on.

 

Yeah, with the strawberry blonde along.

Happy ending!

 

Sweet ride by the way,and by no means do you have to worry about a frozen cracked engine block unless ya come for a visit up north lol.Enjoy

 

Have you tried flushing out all the 50/50 from the block and radiator and coming in with purified water with the royal purple coolant? You'll run 22° cooler. And it works best with a 2800 to 3k cfm fan. I ran that in my 65 stepside on summer days here in o.c. CA she run at 190

 

And take out the tstat. ....

 

I'm gonna say it ,

Pics or it didn't happen

 

Haha nothing more than a walk on the beach and food after. I thought this car was supposed to help get a little further. Maybe next time.