Propylene glycol as antifreeze
Propylene glycol as antifreeze
(OP)
Has any one run tests on head temperature vs coolant temp on plain water vs straight Propylene Glycol coolant?
Someone said they noted higher coolant temp when using PG vs water.
Due to the steam pockets that form in areas of the combustion chamber cooling system using water and PG will continuously wet the metal and not cause these pockets.
If a coolant were receiving more of the combustion chamber heat, would it not show higher temp at the coolant temp sensor?
I would think that it would be necessary to test head temp vs coolant temp using both water and PG to know what was happening.
Someone said they noted higher coolant temp when using PG vs water.
Due to the steam pockets that form in areas of the combustion chamber cooling system using water and PG will continuously wet the metal and not cause these pockets.
If a coolant were receiving more of the combustion chamber heat, would it not show higher temp at the coolant temp sensor?
I would think that it would be necessary to test head temp vs coolant temp using both water and PG to know what was happening.





RE: Propylene glycol as antifreeze
Regards
Pat
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RE: Propylene glycol as antifreeze
And, it's not clear that boiling is that bad, per se. Phase change sucks up huge amounts of energy, to the extent that it might completely make up for the loss of coolant coverage on the HT surfaces.
The most volume efficient heat transfers are often phase change materials (PCMs). Now, typical installations of PCMs are limited usage, since the material volume is limited. In a recirculating system, PC might be OK in some range above boiling point. Just consider boiling in a pot. The vapor bubbles are removed by their own buoyancy and convection currents in the water, and the pot bottom is never liquid free for very long.
TTFN

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RE: Propylene glycol as antifreeze
I know the steam pockets exist in the combustion chamber area of the cooling systems and the use of a pressure system tries to suppress these, so when I read that some stock car builders found that the PG kept the metal wet in those areas and thus required little to no pressure in the system. Thus eliminating hot spots.
I have built an experimental cooling system on my show car and from what all of you say, I really need to test both plain water and PG to see what works rather then accept that PG is the answer. I have ruled out the poisonous Ethylene Glycol antifreeze.
I have thermo couplers to measure actual head temp so I will be able to see what the difference is between the coolant and the cylinder head itself using each as a coolant.
This is going to be used only as a show car so it will not be exposed to freezing weather.
Thanks group.
RE: Propylene glycol as antifreeze
Pure PG's thermal conductivity and specific heat are substantially poorer (30%, 70%) than water's. You only gain 70% increase in temperature, but you'd need something like a factor of 3x deltaT or 3x fluid velocity and radiator area to get the same amount of heat out. A higher fluid velocity would make the pump work harder.
TTFN

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RE: Propylene glycol as antifreeze
You ask if you can use 100% PG in an automotive cooling system and my answer is a qualified 'yes'.
Be prepared for astronomical temps in any marginal system. 300f is not at all uncommon and if the rest of your engine can endure and the oil temp is maintained at a much lower temp, it works. How do I know? I tried it on a Model A Ford. Was it worth the effort? NO, it was not, aside the 'learning experience'. I did not damage anything obvious but the expense and monitoring effort was a waste of time. A new, modern radiator core was much cheaper and more deficient in the long term.
Of course if you are 'pushing an agenda' then, have at 'er, sir.
Rod
RE: Propylene glycol as antifreeze
I mounted a remote water pump and manifold circling the engine to supply coolant to all 14 ports. Yes, part of the reason I want a atmospheric system is due to my complicated external cooling supply system. (limited access to all the external connections) This V-8 is stuffed into an MG.
No coolant travels more than 8 to 10 inches through the engine and all cylinders and all combustion chambers receive the same temp coolant from the radiator. The radiator is a aluminum hot rod radiator designed for a 350 GM and a Jaguar blow through fan is used. With this design I believe I can slow down the speed of the coolant but will run tests to see if that is advantageous or not.
I planed to monitor inlet and outlet coolant temp and actual head temp to get a better picture of what is happening.
This engine has been my hobby and it is started on direct injected compressed air but runs on gasoline.
I ran the engine on a test stand before installation and was able to correct all known leaks and was able to confirm that the carburetors were tuned and ignition timing was correct for all the changes.
RE: Propylene glycol as antifreeze
http://w
Rod
RE: Propylene glycol as antifreeze
I have rebuilt the Rover version 215 for people. I think Rover claimed that the casting process GM used was a problem and they corrected that but visually I couldn't see any other changes.
What ever GM did in the lubrication system and crankshaft design must have been right, as every 215 I pulled down, they all had great cranks in them no matter how worn out the cylinder walls, pistons etc were. Same with the Rover versions.
One of my Olds 215s shows possible signs of what Rover said in that it had the aluminum separated from the cast in cylinder liner. I just use it for fit checks as I have stuffed one in an MG.
This is the MG I am thinking of using the Propylene glycol in.
From what every one says, I better do some testing first.
RE: Propylene glycol as antifreeze
Yes, they certainly do good work and, not outrageously expensive, either...Depending, of course, what level of preparation you are after. We are on our second season with his DOHC Lotus head and the engines leak down is still 3% to 5%, all.
Rod
RE: Propylene glycol as antifreeze
thread108-312238: Propylene Glycol vs. Ethylene Glycol/water
Lot of good automotive expert knowledge presented in that thread.
In the industrial application I described in that thread, boiling point elevation would have been a really beautiful feature for us, but in reality PG provided next to squat. The little bit it gave was a drop in the bucket so to speak.
rmw
RE: Propylene glycol as antifreeze
That's because you need to be close to 85/15 before BP elevation turns the corner on the curve:
TTFN

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RE: Propylene glycol as antifreeze
It sounds like I best just use water with some kind of water pump lube in it since my car is going to be just a show car. If my design of the cooling system cools too well then I may run tests on the propylene glycol.
RE: Propylene glycol as antifreeze
Running 100% PG was informational. I learned that it is totally impractical in any normal automotive application. You can also get some info from articles by Smokey Yunick but you'll need to dig for it.
Rod
RE: Propylene glycol as antifreeze
Poisonous? Go into your kitchen (or store) and take a bottle of vanilla and read the ingredients. PG is one of them. Bon appetite.
IRstuff,
Good info. I had not seen that chart. Problem is, we need the stuff to transfer a significant amount of heat from the process while giving adequate freeze protection when the process is offline worse than we needed the boiling point elevation.
All 3 would have been golden, but we still needed to be able to pump the fluid through some sophisticated heat transfer equipment in a variety of conditions as well. To get the right combination, we can handle the boiling point elevation by raising the system pressure - exactly what the radiator cap does on most autos. We obviously do it with something more sophisticated than a radiator cap.
rmw
RE: Propylene glycol as antifreeze
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Propylene glycol as antifreeze
RE: Propylene glycol as antifreeze
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Propylene glycol as antifreeze
I have had really horrendous corrosion problems in the Al/Fe engines, though...no surprises.
Of course I must volunteer that the 83 year old Ford spent it's entire life here in SoCal, never needing antifreeze. However, I am told by some of the Model A club group that pre war cars used mostly alcohol/menthol or, simply drained the system during winter. I met one fella that said he used 'coal oil' (kerosene) for coolant during winters of the New England area. I suppose it would work...I think I'd want to be careful around open flame, though...;o)
Rod
RE: Propylene glycol as antifreeze
As for running straight water, locomotives run straight water with something like NALCO 2000 rust inhibitor which also works well for the ceramic pump seals.
RE: Propylene glycol as antifreeze
Potential Health Effects
----------------------------------
Inhalation:
No adverse health effects via inhalation.
Ingestion:
Relatively non-toxic. Ingestion of sizable amount (over 100ml) may cause some gastrointestinal upset and temporary central nervous system depression. Effects appear more severe in individuals with kidney problems.
Skin Contact:
Mild irritant and defatting agent, especially on prolonged contact.
Eye Contact:
May cause transitory stinging and tearing.
Chronic Exposure:
Lactic acidosis, stupor and seizures have been reported following chronic ingestion.
Aggravation of Pre-existing Conditions:
Kidney disorders.
TTFN

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RE: Propylene glycol as antifreeze
I use to follow all the tech articles Smokey Yunick wrote in Circle Track mag. He was ahead of most everyone in many areas.
I will post the results of the tests I run on my cooling system later in the year.
Thanks again everyone. This is a great site.
RE: Propylene glycol as antifreeze
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http://www.redlineoil.com/Products.aspx?pcid=10
Rod