VCCA Home Forums GENERAL DISCUSSION General Discussions Cracked Blocks,

Some engine blocks may crack at higher/lower temperatures than others.

32 degrees is the freezing point of water at sea level.

What temperature, then, does our block (216) become vunerable to freezing wate,r sans antifreezed coolant, to the point of cracking the block?

Note: For the above question, forget the so-called freeze plugs" owing to they are not there to prevent freezing temperatures from cracking blocks. They are formed in the casting molds in order to aid in cleaning out the blocks after they have been cast. If you differ on this point then let's merely disagree.

I don't know what the temperature must dip to to crack a 316 cubic inch Chevrolet block here where I am. We're just a little over 200' above sea level, if that matters. I think it may have to dip into the teens.

Lets keep this question pertaining to 216 blocks.

What do you think?

Best,

Charlie

BTW: I think the weakest point of the 216 block is on the left side just below the head. That has nothing to do with the question.

I would say it would take a prolonged temp. of 15 to 20 degress to crack the left side of a 216 block (with 100
% water).

In saying this I realize the freeze plugs dont always work but the theory put forward when I was learning my trade is part of the reason they are there is to relieve the pressure of the freezing coolant, the other part is to aid the removal of the casting sand during manufacture of the block.
As part of the answer to Charlie's question, the pressure of the unfrozen coolant may well be a factor as well.
Tony

Freeze plugs exist because there needs to be a sand core that will become the open space inside the water jacket. Something has to hold that core in position while the hot iron is poured in the mold. It isn't just going to float around in midair until someone gets around to pouring the iron in.

All freeze plugs really do when they pop out is let you know you just cracked the block.

Charlie, the answer to your question is that even 31 degrees would be enough to crack the block if the conditions were exactly right: Absolutely pure water with no impurities, No sources of heat other than the ambient temperature (including not exposed to the sun), and a long, long time at 31 degreesto allow the engine to shed both its own heat and the latent heat of freezing. Maybe two weeks at 31 degrees? Much quicker of course at lower temperatures.

But in practical terms, cars are generally in a garage which, even if unheated, receives heat from the sun, or sitting out in the sunlight where they receive the same heat. And the temperature fluctuates during the day and from day-to-day, so the situation described in the paragraph above would never happen in the real world. Further, the water in the engine is never pure (which lowers its freezing point), and the engine itself is heavy and iron and thus retains a lot of heat and takes a lot of time to actually reach the ambient temperature. So, there is no single answer to your question. It depends on how cold for how long and in what storage conditions.

Nobody in their right mind would intentionally leave an engine with anything less than ample antifreeze protection in the first place. I'd say that practically speaking, if the average temperature (average between daily high and daily low) will be below 30 degrees, you're in trouble with no antifreeze.

Hope that helps.

All the Best,

Chip (aka former Physics guy....)

To add to Chip's post above, water decreases in volume as the temperature drops. At 4 deg. C or 39 deg. F water is its highest density. There is a very slight increase until 0 deg C or 32 deg. F. when the change from liquid to solid begins. Solid water (ice) has a dramatically lower density than the liquid form. [See attached chart] When movement is restricted this increase in volume can exert tremendous pressure. So as Chip pointed out temperatures below the freezing point can be enough to crack and engine block or other container (transmission case, ???).

Retired Chemist with plenty of Physics as well

Here is a picture of a cracked 216 block, left side at the bottom of the water jacket. Cracked the full length...

And here is the after picture, having had it stitched...

If your block uses a non pressurized cooling system, a crack is just an annoyance, and can be fixed with JB weld...

Even 31*, for long enough time, can crack your block, the colder it is, the shorter the time it takes to crack.

Put some antifreeze in, even 25% should be fine for temps of 10F or above.

http://www.erareplicas.com/427man/engine/antifreeze.htm
Doug

My first registered car was a 50 Chevy. When I bought it the freeze plugs were out. I put new ones in and it did not leak. Just dumb luck.

All interesting answers. Especially from the our self proclaimed experts, that is, Chipper and Chip. (Put those two together and you have "Chippendales." When they perform they get lots of dollar bills. Do too!

Anyway, I'm going with Gene on this one. The reason is that for ice to become hard as it can to produce its most pressure and then reach a point strong enough to break the iron casting in the old 216 block.

Now if ice is ice and once ice becomes ice it can not thence become any stronger (in volume) then my theory has no merit.

Our experts, Chipper and Chip, want us to believe that if you have a car with pure water in a shed, then the 32 degrees will create a boat anchor right away. Hmmm?

Chipper says that "water decreases in volume as the temperature drops." Well, I'll have to give that some serious though the next time I heat a cup full of milk for my Gerodelli (sp) hot chocolate.

Now this is the same Physics Major Chipper who missed getting the answer right on the question of changing ratio without changing volume. I rest my case.

Now I want to believe the expert physicists but their instant reasonings give me pause.

I think we need more physicists to join in. We may end up with a group of them convincing us that you can't tell your longitude on earth by the the observing the rotation of four moons of Jupiter and a chart prepared for such observations. (Io, Europa, Ganymede and Colistto. (My spelling needs improving)

Thanks for the replies.

Charlie

BTW: I'm just kidding Chip and Chipper. Neither one would get any bucks for their performances. I've seen Chip and if Chipper is anything like him... You know.

Ghirardelli. Oh my! Talk of sand castings, cores, etc., brings back memory of my days in the Painted Post, NY, Ingersoll Rand foundry where my job was to pull grunts out of the pig iron! Fortunately, never had to deal with a cracked block but have had some experience replacing freeze plugs. Beamer

I was judging by what I saw years ago when anti-freexe was not installed for our cold Wisconsin winters. In the twenty degree weather we seldom saw a block crack. The water would get slushy and not freeze sollid. Bellow that if may freeze solid and push out a welch plug or two if you were lucky.

The water (or liquid) expands when it freezes. That is why when milk would freeze it would push the bottle cap off.

No, Gene.

Remember that a physicist has said that water shrinks when the colder it gets. Accordingly, the colder the bottle of milk is the more it would push the cap off.

Lets keep an open mind here and learn something. Your experience doesn't mean crap when dueling with the more learned.

I still agree with your first post on this thread.

Best,

Charlie

Charlie I think you should go back and study the post by Chipper. Less density to me means greater volume if ice and no longer water.

Think Charlie needs to clean his glasses. Ice wants to occupy a LOT MORE volume than water and dramatically resists movement to relieve the pressure.

An interesting fact is that glycol antifreeze in a mixture of 40% or more with water forms a slush not solid ice. That slush has more volume than pure water but also can flow away and out of the cooling system to relieve the pressure that might crack a casting.

BTW in addition to both Physics and Chemistry training, I spent several years in coolant research and development for a very large antifreeze manufacturer.

...and I have spent many years looking at ice cubes through Kentucky antifreeze..... Have too (as Charlie would say).

All the Best, Chip

And because of the lower density the cubes float on the top even with the reduced density of the golden (or when the ice melts mixed) liquid. Another example of the greater volume versus weight for ice!!!!! Chemistry and Physics win again!

Water occupies less volume as a liquid than as ice or steam but I forget the increase amount.
Tony

Chipper, Please note that I quoted you earlier. Here it it is again verbatim, in capital letters but for clarity not intended to yell as BB cautioned us as not being appropriate. Here tis: "WATER DECREASES IN VOLUME AS TEMPERATURE DROPS."

Those are your words not mine. Do you still insist on the accuracy of those words? I think not.

This thread was started as a serious one but has gone much more scientific than I intended. So be it. I was merely looking for support on my notion that even at the freezing point of 32 degrees farenheith (or even at 31 degrees F) the old 216 block would not freeze enough to bust a 216 block. No matter the length of the period of these freezing temperatures with only water in the block.

I was seeking the temperature that would bust the block overnight when water only was the coolant involved. I still don't know.

Best, and forgive me when I go over the line once in a while when responding to statements and some nonsense.

Thanks for your and Chip's ability to take a bit of kidding.

Best wishes,

Charlie

BTW: Does "wind chill" have any affect on inanimate objects? I don't think so but don't know for sure?

If teh inanimate object is wet, yes, wind chill will drop the temp of the object below ambient. Evaporation cools, whether it is your skin, or a moist object.
Doug

Interesting that we are now at "wind chill".

The "wind chill" number that we hear on the weather is specifically for exposed skin on a human in air. It is a number that tells you how quickly heat is transferring from your skin to the atmosphere. For example, if there is a 20 mph wind on a 10 F day it will feel the same as standing in -9 F with no wind.

The "wind chill" (or really heat transfer number) for a human in water is completely different. Think how comfortable you are in 75 F air but how cold that feels in water.

The temperature of an inanimate object will never go below the actual air temperature in dry air. I agree with Doug about the effects of evaporation. Evaporation absorbs energy.

Now let's take this concept and apply it to the vehicles we drive. There are more than enough posts about overheating to make this relevant. The most common is that an engine overheats while sitting in traffic or moving at a slow speed (parade?). That is because there is not enough heat transfer from the radiator to the atmosphere. When the vehicle is moving there is a "wind chill" effect due to the moving air. The moving air allows more heat transfer. Each radiator has its own "wind chill" or heat transfer chart.

If you spray a radiator with water the temperature will drop due both increased heat transfer (the heat transfer properties of water are different than air) and evaporation as some of the water is converted to a gas (steam).