Yes, but you do get stronger materials ... would en19 or something be another solution if one desires a stronger sleeve, and are willing to machine it from a billet?
What specific characteristic are you trying to improve upon? Like everything else, sleeve material choice is a compromise. In most engine designs, sleeving is a means to improve wear characteristics, not necessarily to improve strength.
Let us know your specific design criteria, and I'm sure somebody will be able to provide you with some answers.
The application is to modify a 1400 turbo engine to a 1600, this increases the bore and only allows for a sleeve thickness of 3mm, with cast iron after a while the sleeves start cracking ... I have access to cnc machines to manufacture any material...
I hate to answer a question with more questions, but I have to. Is this engine a wet or dry sleeve design? Dry sleeve indicates a sleeve that does NOT come into contact with the water jacket or any other coolant passage. A wet sleeve does make up one side of the water jacket, or otherwise comes into contact with coolant passages.
Is the block an open or closed/standard deck configuration?
The reason I ask is that a 3mm ductile iron sleeve in a closed deck, dry sleeve, configuration, should be more than adequate enough to hand a turbocharged 1.6 liter engine. Most 7+ liter turbo diesels I've seen don't have cylinder sleeves much thicker than 3mm.
Finally, finally where in the bore do they start cracking, is it from the top down, or vice-versa? Let me know
It is a wet configuration, but it does have a closed deck, not like honda engines, its a fiat motor, on a uno, the same as the 128...
I personally have not yet tried it, but a couple of people have and they did not say exactly how it cracked, but that when you boost the car high, after a couple of miles(10000) it starts cracking...
Honda's have an open deck, I am not sure which other cars ... it meants that at the top when you look at the sleeves, they are "loose" it is only pressfit at the bottom, what they then do is mill some of the block lower, and then put a deck plate in, now the sleeves a held by the top and bottom.
As ZoRG as already told you, an open-deck is an engine whose cylinders appear to be 'free floating' in the engine block. This method of manufacture reduces production costs, as it allows the mold to be extracted from the top. This allows the same mold to be used many times, instead of a one time use with a sand-cast mold. Also, in some cases, it produces a lighter engine. Honda makes the most use of this technique, applying it to most of the engines they make. BMW, Daimler-Chrysler, Mazda, Nissan and Subaru also have made use of this method on select engines in their respective line ups.
ZoRG,
Sorry buddy, but I gotta throw my hands up on this one. I've read many papers, and the like, on the subject and am getting too much conflicting information. I've read things that seem to think no less than 4130 chromoly will do, while some suggest that hardened aluminum will do the trick.
Honestly, if gray cast iron fits the bill, but eventually leads to cracking, I would think some grade of a decent steel alloy would do the trick. The problem I see with going with too strong of a steel is getting decent ring wear/seal.
I still don't understand the "ring wear/seal" situation, as these days plenty of cars come out with hard coated cylinder walls, the coatings are very thin, however don't seem to be wearing much ... is it not rather the rings that are wearing as appose to the cylinder itself wearing?
Even in this day and age, they cannot mass produce a perfect cylinder. So I expect that if it is made from hard steel, the rings will not even be able to wear off the high spots. If the material is a little softer, the rings can quickly wear the bore on the high point load areas, but will not wear so quick once the load is spread more evenly.
If the bore did not wear in, the wear on the rings would be much faster, and the engine might then need an overhaul even dureing the warranty period.
Also, the factory does not want to have to machine very hard steel, as it wears out their tooling and takes longer to machine.
Cast iron bores mostly outlast the body and trim of the car, and almost certainly last longer than the ownership by the original purchaser.
Bryan
An interresting point about line of draw for the cores. This would allow diecasting, much tighter grain structure in the aluminium, and some control over how the grain lined up, not to mention much higher production rates from each mould.
How do they keep the top of the bores from moveing sideways from the thrust generated by the rod angle. They could use a counterbore in the head and use the cylinder top as a spigot, ar la air cooled VW, but I'm sure they don't go to that much trouble.
I don't know what composition is best, but I know that centrifugal cast is best.
I would guess high carbon and fine grain structure.
Heat treating to gain dimensional stability would also help.
in the 70's I think, Chevrolet introduced a so called high tin alloy block into it's Homologated parts lie up for the small block. I think it is actually high nickle, but appart from that I do not know it's composition. I know these blocks give an improved bore finish after honeing, so the rings seat better. I also know that they resist cracking when compared to the standard Chev block. We could split a bore in a standard block at 800 hp, but we are getting reasonable life out of the high nickle block at 1200 hp. Reasonable life for blown alcohol drag raceing that is.
"Also, the factory does not want to have to machine very hard steel, as it wears out their tooling and takes longer to machine.
"
The turbo-diesel duraMax GM Isuzu engines are made from some secret Japanese iron recipe. After the cylinders are bored they are (induction?) hardened at hundreds of elliptical spots about 10 mm apart all around the bore to form matrix of pretty blue hard spots. Then the bores are diamond honed.
I do not know what the DuraMax ring facing material is. Until an engine is warmed up Ring and cyinder wear can be dominated by corrosive wear, so engines pretty much ignore wear theories based simply on hard-VS-soft. Heck, lubrication details alone can effect wear 1000X. Material compatibility is worth at least 3X.
