Technical SBC 350 - How hot is too hot?

Thanks it has an SW gauge for temp, oil pressure and fuel level.

 

Sorry I re-attached it.

 

To the left of the thermostat housing is where the temp sender should be positioned. Flex fans are junk.

 

Ok If you are standing in front of the car do you see a bolt that is just left of the thermostat housing? That isn't a bolt but a plug. You will need to remove that plug and then put the temp sensor in that hole once the plug is out. Please take pics of the temp sensor once you get that out because you might need an adaptor for it. You are also going to need a plug for the hole in the head where that temp sensor came out. But we will get to that once I see the pic.
Jay

 

Ok.. Good gauges.

 

You will need to drain the coolant right down again. to do this right. You got to make sure there is no coolant in the water jackets of the block or you will have a mess.
Jay

 

Thanks. I did see that plug in the photo just to the side of the thermostat housing. I do remember draining the coolant and adding thread sealant when I re-installed it on the head.

I will take some more photos tomorrow but will plan on doing this work when I can get it done in a day or two that way I don't have another big chunk of downtime.

 

Ok PM me when you get the photos and I will walk you through this. If you want my phone number PM me and I will give it to you also.
Jay

 

Oh thanks so much!

 

Well to be honest I thought the first post was off lost in space somewhere as it went away when my laptop locked up.

As far as theory of freezing, each liquid has it's freezing point pure water being 32F or 0 C At that point the molecules of the liquid begin to turn to a solid. When you add a compatible liquid to the water that lowers the freezing point. The mixture does not generate any heat on it's own though.

Living where it sometimes gets 20 below 0 F in the winters I have always run antifreeze and to tell the honest truth never read the theory that pure water or water with "water wetter" would run cooler until I joined the HAMB. Even the local spit and whittle club never threw that one out nor did any of my students quote their uncle or grandpa on the subject in the years I taught although a couple threw out some wild family quotes.
I wonder if some guys get the idea that a rig runs cooler with plain water because some race associations require plain water with no antifreeze to help prevent a mess on the track if something happens to cause a spill.

 

I didn't see any physics, thermal equlibrium, heat transfer, nor laws of energy. This isn't rocket science level its 8th grade stuff.

You're correct when you say the mixture doesn't generate any heat on its own. Nor did I say that either.

Here's a couple ideas for you to help you get started on proving your point or idea that I spoke nonsense.



Rocket science from NASA

 

31Vicky is right about the pure water. Better heat transfer. (Though in most areas, antifreeze is needed) Also, Water Wetter works in some cases. It is a 'wetting agent' similar to the stuff they use in dish washers or those car wash things. It works by allowing the water to displace any air bubbles inside the cooling system, by making the water adhere to walls of the engine better than air bubbles. Air acts as an insulator to heat transfer. It's not magic, it's chemistry.
Lots of good advice, but lots of myths, too.
Just to add my vote: 180 stat, drain and flush the system well, put the temp sensor in the intake, it will read lower, but more accurately, and more stable. I don't believe you need a shroud, as your fan is pretty close to the rad, but I'd change out that aftermarket looking fan, for a factory heavy duty fan. It will be all steel, and 5 or 6 blades. You should add an overflow tank though, Keeps the water level up to the top of the rad. Just be sure to hook one up correctly, so it doesn't reintroduce air into the system. If you can get your hands on a non contact thermometer, get the engine hot and check temps at the bottom and top of radiator to be sure it's not clogged, and not cooling the engine.

 

Interesting how putting the temp sensor in the Intake will get a lower reading; but even by doing so, it's like tricking the mind as the head temperature ..... the temperature that one was all concerned about...is still the same. Mine is in the head with a 160 TStat.....and that is what the gage reads. Oh well. I'm wondering if his problem may be a faulty water pump .

 

It's an awful lot-
Much like the question "would you like your pizza cut into 6 or 8 slices?" And the vaudeville response of "you better make it 6 because I don't think I could eat 8 slices"

 

Pure water is amazing stuff. We had to run pure water in our stock cars due to contamination concerns of an eventual coolant leak on the track. AF would help to raise the boiling point, no doubt and in street cars it keeps the cooling passages free of corrosion and lubes the water pump.

I had one of the coolest running stock cars at the time. Solid fan, no t-stat, a partial shroud and at race conditions, it ran 190. In the pits after it would climb towards 220. Simple to cool off, keep it running and pour cool water over the top tank.

 

Thank you. I don't think it's a faulty water pump but maybe. I bought the car December 2013 and didn't see any change in the engine temp during operation until I changed the coolant with 50/50 mix in July this year. That is why I opened this thread, I wanted to make sure I wasn't running the motor too hot. It's probably operator error on my end.

I read about some people wanting the temp on the head and others on the intake. I read some people even run dual gauges. I'm not sure what to do. A lot of people suggest running the temp sensor on the intake but do I really need to? If I can get the behavior to be what it was like before I'm pretty sure things were fine. The previous owner ran that setup for a while (the engine was rebuilt though) and he never had problems according to what he told me.

 

Go read a good novel, and quit worrying about it.

 

Thanks so much for the advice. I already bought the 180 thermostat, the one suggested that Mr. Gasket makes. I will drain the coolant and try 20/80. I'm still not sure on needing to move the temp sensor. If I can get the same behavior as before I changed the coolant, I think things are fine. Changing the fan to all steel is a good idea. Out of curiosity the flex fans are meant to flex so the pitch changes under high rpm correct?

 

Yea. I bought the 180 deg stat so at least I'll change it.. I don't feel like moving the temp sensor though. Changing the coolant is a royal pain in a 1 car garage with 1 ft on both sides of the car.

 

The location of the temp sensor doesn't matter..you know that if it's in the head, it will read a little higher than if it were in the intake. The gauge is there for you to see what's going on in the engine. If you know you have (for example) another 30 degrees before it boils over, there is nothing to worry about, at all.

btw every 350 engine that Chevy ever put in a car or truck came with a 195 thermostat.

 

Thanks again. That is interesting too with 195 thermostat used by the factory on 350 engines. I just read on some other threads that some people prefer using 180 on their old rides because the factory used 195 deg on newer cars for emissions purposes and those cars were equipped with computerized systems for tuning.

 

Well, if you're going to change the T-Stat, AND you were thinking of relocating the sensor, now would be the time to do it, as you need to drain the coolant anyways

 

True! I actually have read pros and cons to having the temp sensor in the head vs the intake. I understand I could try 20/80 coolant mix and the 180 stat but not convinced fully on moving the temp sensor.

 

Water cools better then antifreeze but anti freeze has a different boiling point. Old fashioned kill the neighbors dog antifreeze will raise your boiling point over that of water in a pressurized cooling system. I don't know about the new non poisonous stuff that is probably what is approved in Calif.

What you normally see antifreeze used for in a warmer then freezing climate is water pump lubrication. But you can buy water pump lube that you ad to water to use in places like good old sunny southern Calif. So if you prefer water that is what I would do.

water wetter is a bandaid for a bad cooling system. I love these threads where we are looking at one little piece of the cooling system instead of the entire cooling system. My wife's late model runs at 210 all the time, but I don't like my SBC to run that hot if I can avoid it. 185-200 is good operating temp for an early small block.

So here are some things to look at, one is the T stat. 185 is what I run I my motors year around. I don't use a Stant off the rack t stat, they are not good stats any more. I run a moroso or a mr gasket fast acting stat. they run around 11 bucks give or take and work really well. Most perfotrmance t stats have little holes around the perimeter of the stat. That helps with cooling when you are cruising at highway speeds. if you cant swing a new stat you can drill your existing stat 1/8" holes about half a dozen around the perimeter will help a ton.

I make sure that air has to travel through my radiator not around or over it. I can't see your setup but I have been known to take foam rubber and plug all the gaps around the radiator. I don't recall but I am pretty sure that your car should have a plate that goes above the grill in front of the radiator, it keeps the air from traveling over the top of the rad instead of through it.

Your fan only needs to pull air through the radiator at low speeds (in traffic) and a mechanical will work fine is you have a fan shroud. Even just a ring that extends the radiator face to the fan will work wonders (think '62 Chebby here). At highway speed if everything else is up to par that is not a concern.

Water pumps, not all water pumps are created equal. Some do little more that stir the water while others will move as much water as a fire boat. Often rebuilt water pumps needed an impeller and all they got was a new paint job and fresh bushings and seals. I like a flow cooler pump, but there are many after market pumps that work just as well. A quick check of your pump is to leave the cap off and let your stat come open then look in the tank for coolant flow, it should be substantial.

Finally everything else up to par you still have to have enough radiator to cool the motor. old crusty six cylinder radiators don't cool V-8s or even old crusty V-8 radiators won't do the job either. make sure that whatever you are using is clean and that it is not caked with paint or dirt on the outside either.

Oh and stop whining about your bitty garage, work in the street if there is no room in the garage. That's what the rest of us have had to do and we survived just fine.

 

...and your wife's late model engine will last 250k+ miles running at 210 all the time, how long will yours last at 180? (yeah, yeah, I know, apples and oranges)

I never had a temp gauge with numbers on my 55, a few years ago I put some computer data logging stuff on it and drove it around, it was pretty scary seeing what the temp was up to when the stock gauge gets up to the H end of the scale. But the engine didn't seem to mind at all. Strange how our perceptions of what an engine wants might be different from what it really wants.

 

It is designed to run at that temp, its a pollution control motor. LOL

I actually had my small block up to 235 once in Joplin and that was pretty scary, I lost an electric fan. But that is nothing against electric fans I have also tossed a steel fan blade through a radiator before too.

So what you are saying about data logging is that you were pretty blissful prior to data logging?

 

yeah, and I choose to remain blissfully ignorant after removing the data logger. If it boils, I'll worry about it. If not, I'll just keep racking up the miles.

I learned something interesting about the temp gauges on some late models. My wife's truck always reads 210 after it warms up. Till that time that the thermostat got a little out of whack, and then the gauge said stone cold, and the message thing said the engine might be overheating. The gauge isn't actually a gauge, it's more of an idiot light...if the computer is happy with the engine temp, it will keep the gauge at 210, no matter what temp the engine is really.

btw 350s are all pollution control motors, you know. And that has nothing to do with how warm it should run...

 

They started bumping engine temps in the '70s to make the cats work. The wife's is actually a 327 (or 326?) and 210 is its design operating temp. I am not sure actually how hot it is really running, the gauges are controlled by the computer and the computer could be programmed to say anything. LOL

 

Thanks for all the advice. I imagine if I put my temp sensor on the intake it would possibly read 10-15 deg cooler which would put it in the 175-185 when on the highway and 200 sitting in a traffic light. Right now it's 185-190 on the highway, 200 in city streets around 25 mph and near 220 sitting in a traffic light if I've been driving for half hour. As I said before I noticed it 5-10 deg cooler before changing from what coolant was in it to 50/50 mix.

Here are photos of my setup:




I bought the 180 deg Mr Gasket 4364 thermostat yesterday.

 

Those are nice stats. I think you'll like it unless *you got a bad one. LOL

What you are noticing is real world testing at its best, you are able to compare apples to apples because you are using the same engine rad and etc. so you are recording a difference and not just random numbers. Seldom get this sort of information.

*I have yet to get bad one, but you never know when Murphy is going to raise his ugly head.