I remember the Poms used the "Al Fin" process successfully and I think the early Kawasakis also used that process, liners had (coated) stub C/I fins and were cast into an Ally finned barrel.
I remember the Poms used the "Al Fin" process successfully and I think the early Kawasakis also used that process, liners had (coated) stub C/I fins and were cast into an Ally finned barrel.
Strokers Galore!
The Al-fin process
http://yorkshireferret.blogspot.com/...-at-speed.html
Kawasaki, I do remember their WESC process. Wire Explosion Spray Coating. Around 13 wires of around 1.5 mm were tensioned down the middle of the bore axis. They were high carbon wires then molybdenum wires repeating. Each wire was given around 22k volts giving a well audible bang. So much so, the cyl was contained in a heavy steel box, either for noise and/or electrical safety and/or fumes. All done in fresh air. The carbon wire spray hit the aluminium and instantly formed very hard martensite, due to the very high cooling rate, and the following molybdenum spray acted as a lubricant. I think that it was applied to around 80 microns.
We, when at Orbital, did use a couple of samples on our 3 cyl 1.2 litre dev't engines, no issues. I just thought the process was so elegant, but I guess it was either too slow, too expensive or had field issues, as Kawasaki went the Nikasil route in the end.
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
telll us more about the Kawa electrofusion process i knew it was exploding wires i thing cameron descrbed it many yeards ago
what ran the power a Neon transformer on steroids ?
2 stroke suffing was trying diy niksil but it seemed a bit complicated.
the wellworthy was basically described in one of the processes in the PDF
It was first dipped in molten aluminium alloy then cast in place.
the Ribs on the Japanese bikes sleeves give it more surface area and prevent creep.
Some other interesting stuff
https://www.european-aluminium.eu/me...er-linings.pdf
Honda on saving space and money developing a new engine or changing tooling
http://dwolsten.tripod.com/articles/jan96a.html
WHy the back to the future Steel pistons need steel sleeves
https://www.cycleworld.com/2016/01/1...ology-feature/
http://blog.wiseco.com/piston-to-wal...ions-explained
McCulloch, I believe were the first to use the ribbed (threaded) cylinders in their Kart/Chainsaw engines. ....... and I seem to remember seeing a few Kawasaki motocrossers with ruined barrels /pistons from using the Electrofusion process!
Regarding piston clearances, the two stroke has always suffered from the possibility of sudden seizure (most probably being brought on by uneven heating of the piston which in turn comes from the hot exhaust and the cooling effect from the transfers on opposite sides of the cylinder. This in some cases was sorted by greater piston clearances, but in the sixties (that's last century to you young guys!), Suzuki (and most others) resolved it all to a certain extent by testing various cam grinds on the pistons till it was close enough, so the one thing which was could still alter things drastically was jetting expertise on the day!
Watching the 125 Ulster GP I remember seeing the two works Suzukis (in the lead on the first lap) both seize about a third of the way round the track at exactly the same spot! - so there was a definite science involved with it all (but someone got it wrong this particular time!).
The exact same thing happened at Pukekohe to Cal Rayborn from USA - unfortunately he did not survive - I did witness that as well - very sad.
I did hear of works test riders being asked to go out on the track and ride the hell out of the bikes till they seized!! - worrying times for them I imagine!
To me the opposed piston concept could be a winner here (with no uneven piston heating) so it could offer much closer piston clearances and that would help outweigh some of it's downsides! - whatever happens, I will be looking on with interest!
Strokers Galore!
You have a bit more leeway now with gauges hit 1300F on a two stroke and it will almost certainly nip up.
many hours of my youth were spent running and sanding pistons as they nip up slightly, then cleaning up the cylinder and the piston after which you would repeat it about 4 or 5 times afterwards it would be fine unless you did something stupid with the jetting
After a while you could sense it as the engine got quieter when it would be about to happen.
Modern bikes and race pistons i guess would no longer need this ritual.
but i attribute this ritual with the reason i never had a full on piston seizure (along with fat jetting i guess)
Yeah, - poor man's cam grinding! - I did that too (after I had a seizure) - file marks were good for retaining the oil!
In a stroker there is never such a thing as a round piston!
Iron barrels definitely did not help! ..... very dicey things to ride, those old strokers!
Strokers Galore!
Came across this, might be interesting to someone !
https://www.thedrive.com/tech/34775/...ABk9Bqdj8mhV54
Strokers Galore!
Yeah Wil, I think the main feature of the piston is its shape, most likely a product of the "polytropic optimization" method, itself a sophisticated application of FEA. Looking at it, this could be easily a cast item, using sand cores. Cuppla dudes on kiwibiker have come up with almost similar designs, and even parts, for 2 stroke applications. These taking into account the fundamental different design requirement.
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
Ken,
I'm not really up there with all the new terminology or even abbreviated names these days - ( I quite frankly know sweet FA ), but there's no harm in having a stab at things and try to understand what it's all about!
We are both into 3D printing of course (which in itself isn't terribly exciting) but those guys on Facebook etc who believe that 3D printing consists of downloading .stl files and putting them in the machine, pressing the button and hey presto, pointless perfection pops out! - - they make me feel like a genius! ........ cos we actually know how the damn thing works and don't see it as a supersonic precision machine - as they do!
Like everything else it will all settle down and I guess there will be a niche where 3D printing will become very necessary (as it probably is in this case).
Have you done any 'lost PLA casting to date? - seems that there is a type of PLA filament specifically for the 'lost PLA' process - probably expensive but also probably worth a try!
I remember Mike Hailwood giving the EMC a few outings and extracting the best from it .......... also the MZ and the Benelli and various others - made them all look like potential winners! - probably the money didn't pay for his groceries though!
I once did have high hopes for the EMC - and they did make a great effort too!
Wish my Polish was a little better!
Strokers Galore!
Dindnt Wob or someone elese who posted on here work for DR Joe of EMC
prior MZ replica he was using split singles i think based on Puch
Legend was Dr joe received a complete MZ engine in a suitcase someone liberated from the east cloak and dagger style, not sure if its legend or true.
but afterwards his work was i believe closely associated with Rotax?????
he seem to live on for a long time
I didn't know about that, but the fact that Dr Joe was probably a refugee from Germany, I'm sure he had plenty of contacts there! - Degner " of course liberated" a lot of MZ stuff to help with the Japanese effort as well! -
John Hemplemann (from Auckland) also got a ride with MZ! - the name might have had at least some influence (as well as riding skill!).
Strokers Galore!
I think that would have been pure "fable" - can you imagine trying to get past the Stazi with roadholders down your trouser leg - you would have needed some balls to "leg it"if you had to .... (well, you would still have had some at the start of the chase anyway!)
I can remember watching Ernst Degner, Horst Fugner and Werner Krumpholz racing MZ machines and of course Alan Shephard. - that drawing of the MZ engine which reached the 200 BHP/Litre figure.
That was when go Karts were still using deflector pistons! ie except McCulloch who had vaguely the right idea but still in its infancy and Royal Enfield and BSA using the two port Schneurle transfer system (but really, they copied DKW).
That MZ drawing was actually what inspired my thinking about two strokes and ever since, that has been my benchmark! - In those days,we couldn't see past Horsepower figures, not realizing that there was a lot more to it,..... and that has cost the two stroke dearly - horsepower figures were much more important than any thoughts on the way forward!
Strokers Galore!
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