http://www.replikamaschinen.com/porsche912_gallery.htm

Someone posted this on the 911 bird board. The text says, "The engine uses some of the most exotic parts we've seen, including carbon fiber pistons with ceramic rings!"

This is bullshit right? Everything there looks like a BBQ-black Krylon paint job.

i only see carbon coated pistons. combustion chambers are nice and shiny though. (IMG:http://www.914world.com/bbs2/html/emoticons/givemebeer.gif)

Quite some time ago, there was some talk of composite pistons, using a ceramic fiber (I want to say silicon dioxide), which is molded into the shape of the piston. This is then placed into a mold, and aluminum is poured in. The result is something that looks like an aluminum piston, but is substantially lighter and has much better hot strength. I haven't heard anything else about these for 8-10 years now, so I have no idea if the idea has been pursued much. Ideally, these would allow higher compression ratios and less cooling, both of which would give better efficiency.

I seem to remember reading something about pistons with carbon fiber skirts, or carbon-coated skirts. I can't place anything on pistons with carbon crowns. I'm not entirely certain CF would be a good material for that.

Hi guys,
look at this. A german company that is building pistons from carbon (not coated)

http://www.voelkl.net/

(IMG:http://www.914world.com/bbs2/html/emoticons/smilie_flagge6.gif)

CF is plastic. (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif)

I'm not sure "carbon" is plastic however the resin may be plastic. I bet one set of these would be 3 times the cost of a full teener restoration.

carbon fiber does not mean it's plastic. look at the carbon brake rotors used in racing, they are similiar to the carbon pistons. the carbon pistons were used in f1 a few years ago by a few manufactures(renault/ferrari/honda). they also used ceramic(mercedes in particular) pistons and rings. they were out lawed by the fia, but they were contuinued in fim motorcycles(mainly 2 stroke 500 ,kenny roberts used them in his bikes after yamaha left) i would not at all be surprised by these becoming much more common, the have great thermal properties and are extremly light. perfect for low durability motors

CF and ceramics are entirely disparate materials. And CF's simply are plastics, by nature of their resins; you can alter the temperature tolerance and load of the material by varying a resin, but it is the resin that makes it waht it is. There is some useful discussion at Hi Temp Composites

you are right, they could be called plastics, but in a laymans terms they are more like a phenolic aren't they? neat none the less . those coatings have come so far in the last 20 years

Has anyone looked at the sophisticated flow bench with the body clamps?

The head they're "flowing" looks a little... well, worse for wear.

The way those products are manufactured ( pistons, brake discs) they do not use a resin at all in the formulation. That is why they are correctly called: Carbon-Carbon. Many times different formulations of ceramic materials are stirred into the matrix to give the desired properties. Structural ceramics are of themselves extremely robust and durable. Much work has been poured into making piston engines completely out of ceramics--basically, a 125# chevy V-8 would result with the capability of 1000 HP. Many turbos designed over 20 years ago had ceramic turbine wheels.

The matrix and the binders are two different formulations of carbon.

Carbon is NOT a plastic---all living things are based on Carbon molecules.

When pure elemental carbon is added to tools--they become vitually indestructible.

For the general populace--these binders are cost prohibitive--which is why a simple resin is used.

When a resin is called out for, after the " cure" it is then " Post cured" at an elevated temperature / time frame.

The important thing here is--whatever temperature the post cure is finished at--now becomes the standard maximum working temperature of the part made.

How ever this matrix is still less as strong as a carbon-carbon part,

We use these products all the time in the aerospace field--if any of you really knew how those big airliners are actually made you would think twice before stepping into one........but as history has shown, they are quite safe and durable.

Boy you can learn a lot of cool stuff here. (IMG:http://www.914world.com/bbs2/html/emoticons/clap.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)

I agree too. Also re carbon/carbon brakes, clutches, etc., but thought that that terminology excluded "carbon fiber", which was understood in the art to use resin, which IS a plastic (and which itself obviously includes carbon, though that is damn near irrelevant).

I am unaware of any carbon fiber using thermoset resins - do you know if there are any? Aren't they all thermoplastics?

(IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) Yea, the next engine change I do I will take some pics and post them----it will freak you out at how little is holding on a 1 ton turbine engine!!!

Carbon-carbon is made by a process of heating and liquifying regular carbon---this changes the molecular structure into carbon-carbon---somewhere in the alley of 6000 degrees F.

The binders are carbon which is heated to "only" about 4000 degrees F.

Then all is made just like man-made diamonds--they are put into a mold and squeezed with about 100-10,000 tons of pressure, the heat generated by this pressing is more than enough to form the required parts. However many new methods are being developed every day which greatly simplifies this procedure. Has anybody bought carbon brake pads??? Ever notice how the intial bite is quite soft--and then as it heats up the bite is much more strong than any other pad you ever used--

This is the drawback--carbon MUST have heat to perform properly---which is why piston technology has taken sooo long. If a proper warm-up is not attained prior to "getting on it" the piston crowns will seperate from the piston body every time, this is because they are too cool to function properly.

ford and gm made prototype cars that was completly made out of composite material.including every thing the motor was made out of.gm had big problems with there designs,and so most people who where not in the industry never really heard of it.(composites that is )ford made a very reliable motor for there car completly out of composite material so it can be done.both of these cars made it into to regular production,with non composite motors.one of them even kept the composite body. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

My father actually holds a patent on an automated machine for 3 axis weaving of carbon fibers into a very tight billet which is impregnated with pure carbon after weaving, then placed in an autoclave and pressure cooked. After several steps they start machining, voila..... big ole rocket nozzle. Iffn the stuff can stand up to rocket exhaust it'll prolly last in an engine.

The company he worked for prior to retirement (Reinhold) has quite the reputation in that field. He worked as head of the engineering department there for many moons.
He tries to explain some of the things they make but most of it goes right over my haid.

If anyone has any specific technical questions I can get answers to I will.