OT Car repair

[Tegger]

[e-mail] wrote in news: [e-mail]:

And you're clearly no kind of technician.

[Tegger]

Tegger wrote in news:XnsA22BD7E11D55Ftegger@

208.90.168.18:

If you have rust and scale in /any/ modern engine, then you're either lacking in maintenance technique and materials, or have bought from the wrong automaker.

[clare]

I would read Ray's article if I had a Hemmings Subscription. By the way, it's in the August 2013 issue - which I do not have, as I am not a subscriber.

Water Wetter" is designed to reduce hot spots in your cylinder head. It does this by reducing the build-up of water vapor in any superheated areas. The bad thing about having hot spots in your cylinder head (read combustion chamber) is that they can promote pre-ignition - definitely a bad thing. This harks back to Smokey Yunick's theory of "soft combustion chambers". Any sharp edges in your combustion chamber (around valve seats for example) may tend to get very hot (even red hot) during operation. These areas of the combustion chamber can then form local hot spots in the cooling passages. Thus, even though your bulk coolant temperature is well below its boiling point (i.e. your gauge reads just fine), there may be localized boiling in some regions of the coolant tract.

This localized boiling can cause a layer of water vapor to form over the hot spot. This vapor forms an insulative blanket and prevents heat from leaving this area, thus making the hot spot even worse. But reducing the surface tension of the water makes it easier for vapor bubbles to leave the surface of the cylinder head and allows the bubbles to convect heat away from the area. Something that changes the surface tension of a liquid is called a "surfactant". It does not take very much surfactant to significantly change the surface tension of water. Hence, you do not need to add very much "Water Wetter" in order for it to do its job.

An additional benefit of using "Water Wetter" (in conjunction with

100% water) in you cooling system is that water has an extremely high heat capacity. Thus a gallon of 100% water can carry more heat away from you engine than an equivalent gallon of 50/50 water and coolant. Water also has a high thermal conductivity which increases the convection of heat away from the coolant passage walls and into the free stream of the liquid flowing through the passages.

From:

And are you also aware that "vapour phase" cooling is more efficient than liquid cooling?? It takes a LOT more heat to cause a liquid to boil than it does to raise the temperature of the liquid. Water's latent heat of vapourization is just over 970 BTU per lb. That means it takes about 5 times as much heat to boil a pound of water as it does to heat water from freezing to boiling. So vapourizing that bit of water does more to cool the hotspot than heating the water would - as long as 212F is not a critical temperature to the engine component.

Not saying that localized boiling is good for today's automotive engines - but vapour phase cooling is as old as the internal combustion engine and as modern as tomorrow.

The What and Why of Waste Heat Recovery

One of the most important equipment components in an engine driven equipment installation, particularly Co generation installations, is the Waste Heat Recovery System. This system must be designed to FIRST provide positive engine cooling and SECOND obtain maximum economical heat recovery while insuring reliability and longevity of equipment.

As a "rule of thumb," reciprocating engines are 30% efficient. That is, of the fuel energy input; 30% goes to shaft horsepower; 30% to jacket water heat; 30% to exhaust heat; and 10% to radiation, oil heat, and other losses.

One of the oldest and most successful forms of heat recovery employs VAPORPHASE (ebullient) cooling of the reciprocating engine. The process of the Ebullient cooling involves the natural circulation of jacket water at or near saturation temperature and engine cooling is accomplished through utilization of the heat of vaporization. This is the simplest and least costly form of waste heat recovery.

Some of the benefits of VAPORPHASE cooling are, elimination of the jacket water circulating pump, extended engine life due to uniform temperatures throughout the engine (normally 2-3 degrees differential between inlet and outlet), recovered heat in the form of low pressure steam (up to 15 PSIG) and all of the heat rejected to the jacket water is recovered.

- From

You want to do some real scholarly reading on the subject of "nucleat boiling" in internal combustion engines???

Read

You don't even need a subscription. Nucleat boiling already serves a very strong role in automotive engine cooling, and will become much more commonly exploited in the future.

Want some more reading to educate yourself on the physics of boiling, and the science of automotive coolants/cooling???

Read this:

[clare]

When you are a professional mechanic / technician you work on vehicles of all kinds - from all manufacturers, and with all levels of maintenance. Not all customers follow the manufacturer's specifications, or take their mechanic's advice. So you need to be prepared to service and repair vehicles in all kinds of conditions. So you NEED chemical flushes for some vehicles. It returns the cooling system to serviceable condition - at least partly undoing the "damage" done by inadequate serviceing. It is part of the maintenance teqnique and materials REQUIRED to service some vehicles.

And if you do a coolant flush and change without actually flushing and cleaning the cooling system, and you leave 25% of the old coolant in the engine, you are comitting fraud. You can get away with that on your own car, but not on a customer's car.

It's been 41 years since I got my mechanic's licence - 10 years of that spent as a dealership service manager. Hundreds of happy, satisfied customers. Because I made sure their vehicles were properly and effectively serviced.