Ask an Engineer

[husaberg]

There's been a lot of things tried - read the old books.

The neatest one I know of was Herman Meier when he was developing the Royal Enfield 250. He did a chrome plated alloy sleeve which was of a different alloy to the cast barrel - get the right interference fit and temperature differential and it dropped out. Slip fit at room temp but stuck fast when hot....easy to change things.

Most continental and british sleeved cylinders are a plain parallel wall sleeve. Unfortunately most Jap cylinders since 1970 have been odd shaped liners cast in.....

I think that Wellworthy invented the cast in sleeve or at least patented one form of it which is very British...........
trying to avoid the cost of the plating but yes it way be unavoidable.

What would be the pros cons on a threaded cast iron sleeve in execution rather than vs Niksil.
Also some suggested reading material Greg.

[Ocean1]

I've thought about it. Never had sufficient cause to try it. The surface contact area thing's not clear cut, either, if you look closely at a good quality commercial bolt you'll see the thread form is rounded at the peaks, in a nut the minor dia peaks are flattened. Typically just 75% of the theoretical mating faces actually contact. With careful machining you could optimise the profile and get that up around 90%, but whereas it's reasonably easy to achieve good surface contact with a smooth cylindrical liner even with ground threads I doubt you'd get anywhere near that 90%. And you ain't going to grind the internal alloy thread anyway.

Long and short: good idea if you assume perfect threads, but very difficult to execute.

Not sure what would prompt a departure from chrome on alloy. You've got the best of both worlds, very hard surface chemically bonded to a lightweight structural material with a very high thermal coefficient. And relatively cheap.

Now that I think about it what implications would ceramic bore coatings have wrt heat? I guess if not much heat's transfering into a ceramic cylinder wall you don't have to get rid of it, eh? OTOH a colder cylinder could cause grief with combustion dynamics...

[husaberg]

I've thought about it. Never had sufficient cause to try it. The surface contact area thing's not clear cut, either, if you look closely at a good quality commercial bolt you'll see the thread form is rounded at the peaks, in a nut the minor dia peaks are flattened. Typically just 75% of the theoretical mating faces actually contact. With careful machining you could optimise the profile and get that up around 90%, but whereas it's reasonably easy to achieve good surface contact with a smooth cylindrical liner even with ground threads I doubt you'd get anywhere near that 90%. And you ain't going to grind the internal alloy thread anyway.

Long and short: good idea if you assume perfect threads, but very difficult to execute.

Not sure what would prompt a departure from chrome on alloy. You've got the best of both worlds, very hard surface chemically bonded to a lightweight structural material with a very high thermal coefficient. And relatively cheap.

Now that I think about it what implications would ceramic bore coatings have wrt heat? I guess if not much heat's transfering into a ceramic cylinder wall you don't have to get rid of it, eh? OTOH a colder cylinder could cause grief with combustion dynamics...

Niksil and the others are i believe semi ceramic click the arrow Chrome is old school and not so good for 2 smokes.

here

[Ocean1]

Niksil and the others are i believe semi ceramic click the arrow Chrome is old school and not so good for 2 smokes.

Apologies, I meant "whatever shiny stuff they're electroplating onto alloy bores nowadays", rather than actual simple chrome.

I'll read that wee article when I've got half an hout to figure out how to size it so I can see it and have it STAY that size. However, I'll bet you a pound to a pinch of shit it involves nickel and I'll be surprised if it doesn't involve chromium.

[husaberg]

Apologies, I meant "whatever shiney stuff they're electroplating onto alloy bores nowadays", rather than actual simple chrome.

I'll read that wee article when I've got half an hout to figure out how to size it so I can see it and have it STAY that size. However, I'll bet you a pound to a pinch of shit it involves nickel and I'll be surprised if it doesn't involve chromium.

click on it click again until to see an magnifying glass with a + and click again like magic...........
the one below has already been resized so just click.
Do all engineers have beards and Glasses?

[Ocean1]

click on it click again until to see an magnifying glass with a + and click again like magic...........

Cool, cheers, it even works

And nicasil = nickel and silicone, whoda thought?

Do all engineers have beards and Glasses?

That's Masons innit? Nearly the same I suppose.

[pete376403]

...As an aside i see the new Yamaha 150 or 125 four stroke road bike has a non coated alloy cylinder with i believe a very high silicon content.

Google Chev Corvair Flat 6. In 1960 they were using a high silicon content aluminium for the block, after finished to size it was etched in some way, the ali was eroded leaving peaks of hard silicon for the rings to bear on. I guess the patent must have expired...

Another variation was Kawasaki Electrofusion. What I read (Kevin Cameron) said it involved a very high voltage applied to a wire of some material down the centre of the cylinder. The wire would 'explode" driving the material into the aluminium

[husaberg]

Google Chev Corvair Flat 6. In 1960 they were using a high silicon content aluminium for the block, after finished to size it was etched in some way, the ali was eroded leaving peaks of hard silicon for the rings to bear on. I guess the patent must have expired...

Another variation was Kawasaki Electrofusion. What I read (Kevin Cameron) said it involved a very high voltage applied to a wire of some material down the centre of the cylinder. The wire would 'explode" driving the material into the aluminium

i wasn't aware of the Corvair but i had heard the same re the Kawa electrofusion.
The idea behind the Idea of the screw in liner iron was to achieve reasonable thermal propertied without the cost of plating/coating plus the molds i have are designed around a 54mm, not a major issue but i was trying to keep costs down to a affordable level for the masses. Also to avoid the hassle of multiple mold changes.
This is the Yam system
The article i had linked had the squuze form liners that the same company did years before Yamaha as well but i think they still had a coating of some sort

http://etalkindia.com/talk/automobil...50cc-bike.html

Also, Yamaha has implemented new DiASil Technology which makes engine more efficient in power handling. DiASil Cylinders are all-aluminum cylinders made by YAMAHA’s proprietary aluminum die casting technology. An aluminum alloy with 20% silicon content is used to create a very hard, reliable cylinder surface, making conventional iron sleeves obsolete. As a result, the entire cylinder can be made of aluminum, a better conductor of heat, which means the cylinder delivers better heat dissipation and less weight. (Aluminum’s heat conductivity is 3.1 times that of iron.)

http://www.yamaha-motor.co.jp/global...nnovation.html

YZF R15 makes use of DiASil (Die-casting Aluminum-Silicon) cylinder. The DiASil Cylinder is an all-aluminum cylinder made possible by an exclusive Yamaha aluminum forging technology. Because it uses a 20% silicon aluminum alloy, it is possible to create a cylinder wall that is so hard and durable that it eliminates the need for a conventional steel cylinder sleeve. And, because the cylinder is all aluminum, it has excellent heat dissipation qualities (cooling capacity is improved by 60% and reduces engine weight (by 30%) at the same time.http://www.vicky.in/straightfrmthehe...orial-preview/

[Grumph]

Reading material - anything by Pil Irving. I do keep coming back to him but as someone said, the old B was right more often and earlier than most....

The problem you face is that 99% of the methods that have been invented for bore linings - transplant coatings, trick cylinder materials, whatever, are intended to make mass production cheaper. Hence they are both capital intensive and plant intensive - ie, they cost a lot to set up and need f'n big bits of gear to do....

The low volume one off - or say less than 10,000 unit production run is still best served with the simplest methods...
Sand cast barrel, parallel iron liner shrink fitted....

Ask NZ Cylinders in Ashvegas for a price...then ask someone with a lathe to turn up a plain liner for you...
Or just keep buying the lotto tickets, your choice.

[bogan]

Any good ways to glue nitrile rubber to aluminium for long term use exposed to fuel?

[Ocean1]

Any good ways to glue nitrile rubber to aluminium for long term use exposed to fuel?

I've used 3M scotch-weld 847 to glue fuel tank gaskets on with some luck.

Probably good to deal with any aromatics lurking on the surface of the rubber first.

[bogan]

I've used 3M scotch-weld 847 to glue fuel tank gaskets on with some luck.

Probably good to deal with any aromatics lurking on the surface of the rubber first.

Mint, and best way to remove aromatics? just wash em and dry em good or are chemicals needed?

[husaberg]

Mint, and best way to remove aromatics? just wash em and dry em good or are chemicals needed?

there is a thread I posted about a guy who made inlet manifolds (reed rubbers) at home for a RD somewhere.

he describes the whole process on a page somewhere.....

[Grumph]

Any good ways to glue nitrile rubber to aluminium for long term use exposed to fuel?

There's at least one place in ChCh who can vulcanise same. Try the yellow pages local to you for rubber bits makers - rollers etc.

[Ocean1]

Mint, and best way to remove aromatics? just wash em and dry em good or are chemicals needed?

MEK from memory, and I roughed the surface up a bit with emery tape just for the hell of it.

Lookie here: http://multimedia.3m.com/mws/mediawe...6EVs6E666666--