Test Engine

[Anonymous]

I'm putting the head back on my test engine. This is the engine that has been sitting for 5 years. While the head was off I was using the air hose to blow everything off on the top end. While I was at it I stuck the air nozzle down in the water jackets. Besides getting a lot of rusty, dusty crap out of the water jackets I also got two large cock roaches and a gecko. I'm wondering why we use coolant to cool our engines and send it to the radiator to be cooled by air. Would pumping air through the water jackets not accomplish the same thing? No more antifreeze. No more radiators and radiator hoses. No more heaters. Burrrr. But this is Texas. We don't need heaters.

 

[StrangeRanger]

Water coducts many, many times more heat per pound than air and it takes many, many more cubic feet of air to add up to that pound. It can still be done with proper fans and ducting as VW and Porsche have proved, but it still leads to uneven running temperatures which in turn has a negative effect on emissions control. Basically air cooling has been tried and found wanting, even Porsche has finally abandoned it. AFAIK only the Tatra trucks are still air cooled, aero engines notwithstanding.

 

[Lazy JW]

As a longtime driver of VW's in northern Idaho I can attest to the lack of heat Even the very best air-cooled engines burn subtantially more oil than a good water-cooled engine. This is due to the wide fluctuation of temperatures inherent in the design. Adding enough cooling fins to equal the heat disipation of water would result in an engine somewhat heavier than a water-cooled engine, thereby defeating the primary advantage of air cooling. As StrangeRanger mentioned, smog control was partly what ended the sales of the venerable Bug in the US. That and the competition from those pesky water-cooled Japanese cars (Yup, their heaters actually WORKED) Diesel engines are actually a better candidate for air-cooling because they don't have as much waste heat to dispose of. Those Deutz diesels got pretty impressive fuel economy to boot. And don't overlook the air-cooled powerplant in the M-60 tank, still in use by the Marines 8)
Joe

 

[Thad]

IIRC water has 24 x the thermal carring capacity as air.

 

[83F150]

The M60 tank is air cooled?

I bet that works well in 120* Desert heat.

 

[Lazy JW]

The M60 tank is air cooled?

I bet that works well in 120* Desert heat.

Actually better than you might think. Lots of tanks have used air-cooled engines as they are less vulnerable to damage and can save weight when properly designed. They never boil over, and they never freeze up. A light weight, durable powerplant is highly desireable in a vehicle that EVERYONE wants to destroy Why worry about weight in a tank? Because every pound saved can be an extra pound of armor or ammo. Remember the part about everyone wanting to kill tanks? No tanks for me, a moving foxhole attracts the eye
Joe

 

[StrangeRanger]

The M60 tank is air cooled?

I bet that works well in 120* Desert heat.

The Tatra trucks are air-cooled 2-stroke 4WD turbo-Diesels. Karel Loprais's Tatra is one of the top racers in the annual Dakar, only occasionally (OK 3 of the last 4 years but who counts) beaten by Viktor Tchaguine's Kamaz team. If they can race flat out across the Sahara for two weeks straight, they don't seem to have an overheating problem.

 

[mikulh]

What about an oil cooled engine using a setup similar to the water cooled engines?

 

[StrangeRanger]

The only automotive engine that I know of which tried this was the short-lived Porsche F1 engine of the early 60s. They abandoned the idea.

Rule of thumb: if Porsche can't make it work, it won't work.

 

[80broncoman]

One of the guys at work has run demo derby cars for years. I told him he could postpone overheating by running a LARGE oil tank (as in nascar) and a large oil cooler, of course placed in a better place than the typical location .