Someones explanation of how water cools an engine - agree or not???

I thought the notion of using phase change sounded wrong. I always thought any auto engine producing steam at any location in the cooling system was "about to blow". Lots of good posts, thanks.

Well, I ve been doing much the same. Took down three trees, had the stump grinder come out and make mulch of them. Grinder was $275, but it was worth it.

I am not going to hassle you anymore about your post, but I will make the statement that in most auto applications, the oil does not cool as much as the water based coolant. The physics just isnt there.

Slept in your car, did you? I have been to a bunch of places in other states and Mexico too.I always slept in my van.I had a foam mattress attatched to a piece of plywood to sleep on.And I had an old spare battery for my 12 volt electric fan and a one burner small propane cooker thingy.It was just like spending the nights at a ritzy hotel.

In November of 1971 I bought my 1914 Ford T Model from a guy in Sioux Falls,South Dakota.I brought my car home in a U-Haul truck.I was running low on gas when I got to Kinsley,Kansas, it was around 11:00 PM.I spent the night in the cab of that U-Haul truck right there in the parking lot by the gas pumps at a Vickers gas station.The gas station didn't open untill 9:00 AM in the morning. cuhulin

snipped-for-privacy@webtv.net wrote in news:21128-4B6F0F7C-4117@storefull-

3172.bay.webtv.net:

Dig out around the stump so you can cut the roots off the stump itself. Then you just have to cut the taproot if there is one. Use a chainsaw. If you can't see what the chainsaw's doing, you haven't dug out enough. Take your time with the digging and do *not* try to lift the stump out. Push it with your foot to see if it's loose. The best time for this is once you've cut the roots all around. If it doesn't move easily, you need to dig some more. Roll - *don't* lift - the stump out. Then you just have to fill in the hole again. Nothing will be above ground level.

The math about how many calories you get converting water to steam is correct.

The rest is rubbish, because it neglects the fact that you need a steady FLOW of heat energy away from the metal walls of the combustion chamber in order to effectively cool it. If a layer of steam forms against the metal wall, heat CONDUCTION across that band of steam plummets, and so the metal gets hotter and hotter in a runaway fashion, making the steam layer thicker, which then reduces heat flow further, which heats the metal more, which further thickens the steam layer... etc. until the engine fails.

Modern cooling systems (and by "modern" I mean post WWII) are built specifically to PREVENT "microboiling" and steam pocket formation wherever possible and operate by direct thermal conduction to the water, which is then rapidly swept away to the radiator and cooled by thermal conduction again.

The reas> I ran across this explanation of why oil would make a poor coolant

I stand by what I said before, oil cools more than water, in auto engines. cuhulin

In auto engines, most of the heat is expelled in the heads and exhaust. In water-cooled engines, the heads are water cooled. Oil carries heat away from bearings, a little from cylinder walls, and a very small bit from the heads via lifter oil flow and rocker lubing. But oil is mainly for lubrication. The water cooling keeps the oil from getting too hot, and carries away heat the oil never even sees. You're right if you're talking about air-cooled engine though. Because there's no water in them. That's my best guess. I'm not an auto engineer.

--Vic

I believe that oil often does play a significant role in cooling the

*pistons* - if your rods have a little hole above the wristpin, that's the oil jet that sprays oil on the underside of the piston crown. Not all engines have this, but some do.

nate

My understanding is, with water-cooled engines, the oil does something like 5% of the cooling. With air cooled engines the oil does about

30% of the cooling. Always keep the oil 'topped up' on air cooled engines.

Didn't all the air cooled VW Bugs come with a oil cooler as standard equipment? My understanding is the early VW's didn't even have a gas gauge, but came with an oil cooler!

Yup, it sure did. I guess simply blowing air over the fins of the jugs wasn't enough, otherwise Herr Dr. Ing. h.c. F. Porsche wouldn't have included it, seeing as the whole concept was to keep it as simple as possible.

nate

The air-cooled VW type-1 did have an oil cooler located inside a fan shroud. The cylinders and oil were cooled by air blown through the shroud. The air was moved by a fan which was attached to the generator or (in later models) alternator shaft which was driven by a belt. It was a pretty nifty setup.

The old VWs did not have an oil filter but did have a mesh screen which I guess filtered out bugs or leaves? :-) This might mean that if you change the oil often enough, a filter is not that important. Hmmmmm.... :-)

My 1961 VW van and my 1963 VW beetle car and my 1971 VW van I used to own had gas gauges.The mesh screen oil filter used two round gaskets.I used to buy new gaskets, wash out the mesh screen with gasoline and put it all back together, except for the old gaskets, of course.

I wouldn't mind if I could find a good old VW van that I can fix up and drive.There is a guy near me (about a mile or so) who owns his own VW repair and paint shop, he works on old air cooled VWs too.I might get over there someday and ask him if he knows of any old air cooled VW vans for sale in the local city metro area.I am not going to travel long distance to check out anything.I like to be at home every day before night time rolls around. cuhulin

Those VW Type 2 are pretty cool. The really old ones with the safari windows are way cool. Too bad that an integral part of the van's bumper system is the driver's shins. My suggestion is the you get those shin guards of the type soccer players use so that the rescue workers will have a little easier time extracting your body from the wreckage. I've never had a VW van before but I did have an old Toyota van that had a similar design philosophy. Just thinking about it makes my shins throb. :-)

In message , M.A. Stewart writes

Yes, looking forward, in the airflow toward the front left cylinder, which because it ran hotter that the other three had greater clearance between piston and cylinder.

Correct, instead of a gauge, they had a lever so when the fuel got low and the engines started to splutter you turned the leaver and this gave you a reserve of about an Imperial gallon. You had to remember to turn this lever back on filling, or you don't have a reserve and when out of fuel you were stuck.

In message , dsi1 writes

This design is called Forward control and is common in Europe where lengths are limited, I will point however that the second VW van of which you mention has an RSJ around the footwell and in a crash with a car I'd be better protected by the RSJ than by any bit of a car.

In message , dsi1 writes

I think you mean "if you change the engine often enough." I am not sure when VW added the oil filter but it was as big an advance as adding the gas gauge and a real gas pedal.

--scott

Where are the old style Volkswagens still being manufactured? I visited Mexico for five days in June of 1992.I saw a lot of old style VWs there. cuhulin