titanium block
- Thread starter theon
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As a youger man we used titanium dioxide as a coloring agent in the "cultured marble" products we produced. You can find titanium dioxide in all sorts of products, paint being one of the most common.
I wonder if it is produced by oxidizing (burning) titanium dust??????
Just proof that this mind wanders a bit too far at times!
Doug
I suspect if titanium had any advantage over aluminum cylinder blocks you would see it used in F1 engines. Rods, now that's another matter.
I think the cost of material would be prohibitive-- a 12" x 24" X 2.5" Grade 2 plate runs $11,000 (retail), and I'm not sure there's be that much advantage from an engineering standpoint. The old saying, " Better is the enemy of 'good enough' " may apply here.
IIRC titanium isn't allowed in F1 blocks. Or is that Magnesium?:uneasy:
Titanium and aluminum are used a lot in bicycle frames. I am no metalurgist, but aluminum frames are generally lighter and more rigid than titanium. This is due to the fact that aluminum is less dense, so you can use bigger diameter tubes that are stiff but are still light.
With the same volume of material, the Ti block would be heavier. And the equipment necessary to machine it would be that much more expensive too.
The world of cycling has many examples that demonstrate the concept of certain materials being ideal in certain circumstances.
That being said, composites seem to be able to be designed for almost any application. I wonder about a carbon block with sleeves?
With the same volume of material, the Ti block would be heavier. And the equipment necessary to machine it would be that much more expensive too.
The world of cycling has many examples that demonstrate the concept of certain materials being ideal in certain circumstances.
That being said, composites seem to be able to be designed for almost any application. I wonder about a carbon block with sleeves?
I've tried machining titanium on my lathe and my mill - it's a bitch. Much, much more difficult than hardened steel. Even the best carbide bits really struggle to get a bite, and when they do it takes a load of hp to maintain the proper machining speed.
Titanium works OK for rods because they're generally forged and not heavily machined (just the ends for the bearings) whereas there's a lot of machining for a block relatively speaking. I would think the machining costs would be extraordinarily high. This, combined with the raw material costs, probably make it prohibitively expensive even for supercars.
Titanium works OK for rods because they're generally forged and not heavily machined (just the ends for the bearings) whereas there's a lot of machining for a block relatively speaking. I would think the machining costs would be extraordinarily high. This, combined with the raw material costs, probably make it prohibitively expensive even for supercars.
Titanium has great a strength-to-weight ratio, but its stiffness-to-weight ratio is slightly less than aluminum. Because its density is roughly 50% higher than aluminum, in order to maintain a similar block weight, the thickness would have to be thinner. But there's a problem. At least some of the efficacy of block design comes from "beam (bending) stiffness", which increases by the square of the section thickness. The bottom line is that most of the time you're better off using a less dense material with equivalent stiffness.
Mclaren were developing a Beryllium block for F1 before the FIA got wind of it and banned Be on the grounds of cost and health & safety. Quite right too as its ruinously expensive and quite poisonous as well - however it is far stiffer and lighter than Ti. What happened to ceramic blocks? They were all set to be the thing 10/15 years ago.
The machining problems with titanium aren't limited to just turning and milling either. The sheets "spring back" 5% or so when you bend them, and the stuff work-hardens and has to be heat-treated in a controlled atmosphere after every forming operation. The only alloy I know that comes close in the royal PITA to machine category is Inconel.
I can't imagine how you would make a practical engine block from ceramics. Although it's great in compression, it's lousy in sheer, tensile, and torsion. We tried ceramic gate valves in the oil patch in the '70s and found that they could not withstand thermal shock, impact, or close contact with materials with different coefficients of thermal expansion - all of which happen to an engine.
I can't imagine how you would make a practical engine block from ceramics. Although it's great in compression, it's lousy in sheer, tensile, and torsion. We tried ceramic gate valves in the oil patch in the '70s and found that they could not withstand thermal shock, impact, or close contact with materials with different coefficients of thermal expansion - all of which happen to an engine.
Well its not easy (ceramic) or everyone would be at it. There was a commercially available 2 ltr 4 cyl race engine some years back - one was being run in a UK hillclimb car. My cousin spent two years heading a research project for Ford into ceramic heads which concluded that there were big problems with valvetrain vibration due to the lack of damping in the material. It could be overcome but at an uneconomic cost.
Other weird and wonderfull materials: Aluminium/Boron MMC, used in brake calipers in F1 until banned by the FIA.
Other weird and wonderfull materials: Aluminium/Boron MMC, used in brake calipers in F1 until banned by the FIA.
Do you know if it was a solid, all ceramic block or perhaps a plasma spray coating over an alloy?
Polimotor Engine:
It was solid ceramic (torlon) block and heads. I also seem to remember it being American in origin. There was coverage in Racecar Engineering V4N4. Google 'polimotor' and it wiil throw up quite a lot of info.
It was solid ceramic (torlon) block and heads. I also seem to remember it being American in origin. There was coverage in Racecar Engineering V4N4. Google 'polimotor' and it wiil throw up quite a lot of info.
Jim Rosenthal
Supporter
The Kirkham brothers (Kirkham Motorsports Home Page) have a machined aluminum 427 sideoiler block. It accepts 427 internals but has some changes having to do with the nature of the way it is made. They use two solid blocks of 6061T6 aluminum alloy to make the two parts of it (the part line is on the main bearing as you might expect and the whole thing bolts together using steel studs and inserts). The assembled block and main girdle assembly weighs 75 lbs. I think there is a photo or two of it on their web site. It is also set up for dry sump lubrication etc etc- all the trick racing stuff.
Titanium is evidently a less-than-ideal material for piston engine blocks, although it might have some advantages in rotary engines such as turbines or Wankels. Porsche has used titanium con rods for years in high-performance engines, but the blocks are aluminum. I think any advantage (if any) you'd realize on weight from a Ti block would be offset by the cost, the machining problems and the spatial stability, but I don't know. One thing for sure; you wouldn't have a lot of corrosion issues. Ti is pretty high on the galvanic scale, from what I recall.
Titanium is evidently a less-than-ideal material for piston engine blocks, although it might have some advantages in rotary engines such as turbines or Wankels. Porsche has used titanium con rods for years in high-performance engines, but the blocks are aluminum. I think any advantage (if any) you'd realize on weight from a Ti block would be offset by the cost, the machining problems and the spatial stability, but I don't know. One thing for sure; you wouldn't have a lot of corrosion issues. Ti is pretty high on the galvanic scale, from what I recall.
Boy, that would be an interesting project, I think Kirkham is all set to machine a prototype for you. I think people have used magnesium for blocks in the sixties on occasion. .06 lb/in3 Aluminum is .1 lb/in3 and Iron is .3 lb/in3. Titanium has issues beyond machining. It frets like crazy, so it would be a pain to be constantly rebuilding, pressing in liners, etc. Titanium is great when you can't get past the fatigue or temperature limits of aluminum. So on connecting rods, rocker arms, spring retainers, even springs it can be an expensive but necessary material. I would love to build an engine with titanium valves, rockers and rods, but in general I'd never get the benefits beyond bragging rights
With an engine block, in a lot of spots you need minumum material thickness, which probably relegates the idea of using titanium to the way-back of the list because the ultimate weight savings would probably not be there.
The price of titanium is huge right now also, I think the block of material before it's machined would be $15k or more. You could make a cast titanium block for a lot less I supsect in a volume run of blocks.
Lately I've seen Aluminum-Magnesium Rocker arms which seems like a "newer" exotic material that might have weight and strength advantages over other aluminum alloys, at least in what I read.
With an engine block, in a lot of spots you need minumum material thickness, which probably relegates the idea of using titanium to the way-back of the list because the ultimate weight savings would probably not be there.
The price of titanium is huge right now also, I think the block of material before it's machined would be $15k or more. You could make a cast titanium block for a lot less I supsect in a volume run of blocks.
Lately I've seen Aluminum-Magnesium Rocker arms which seems like a "newer" exotic material that might have weight and strength advantages over other aluminum alloys, at least in what I read.
