Got the bastard, ring feeder was the fix
Got the bastard, ring feeder was the fix
It must be a female..
[QUOTE=WilDun;1131022862]To quote a famous Kiwi -" Well Neil, we knocked the bastard off".
But I'm still confused (as you'd expect), no sprues/risers? - just a ringfeeder?[/QUOTE
I'd already cut them off for the photo. I'd like at least two of these cylinders but seems I've damaged my crucible, It's got a crack running up it. Novus? Best I order another one now as it might take a while to get here from Mexico, apparently where they are made.
Sorry, just noticed where one of them was in the second photo.
Yes, a cracked furnace is something that can be tolerated but a cracked crucible is something else!
Strokers Galore!
Strokers Galore!
If you are meaning the surface of the valve It will have a slippery coat of something along the lines of Ti Nitrade
or are you meaning the pic with the valve inside the guide
oh this one?
The stem of valve, complete with low friction texture surface coating for improved oil retention - remember, a hydrodynamic film is not easy sustain on a reciprocating valve stem and it is relying more-so on boundary lubrication. On close inspection it does look more like PVD coating but further testing required to be certain, the 'roughness' certainly does aid oil retention
PVD
https://en.wikipedia.org/wiki/Physical_vapor_depositionPhysical vapor deposition (PVD) describes a variety of vacuum deposition methods which can be used to produce thin films and coatings. PVD is characterized by a process in which the material goes from a condensed phase to a vapor phase and then back to a thin film condensed phase. The most common PVD processes are sputtering and evaporation. PVD is used in the manufacture of items which require thin films for mechanical, optical, chemical or electronic functions. Examples include semiconductor devices such as thin film solar panels,[1] aluminized PET film for food packaging and balloons,[2] and coated cutting tools for metalworking.[3] Besides PVD tools for fabrication, special smaller tools (mainly for scientific purposes) have been developed.[4]
Common industrial coatings applied by PVD are titanium nitride, zirconium nitride, chromium nitride, titanium aluminum nitride.[5]
all the Ti Nitride i had previously seen was surface ground like a fork leg
interesting stuff.
From what i understand a lot of vlave guides are now made from aluminum bronze not sure re the racing stuff though.
Last edited by husaberg; 10th January 2017 at 18:26. Reason: found the correct pic
Kinky is using a feather. Perverted is using the whole chicken
Guides - from around the mid 80's a lot of production japanese valve guides were an iron based sintered material - hard as buggery too.
I've yet to find a better material for race guides than bronze of one variety or another.
The seats on that F1 head interest me. Beryllium copper - which is illegal now. I'd suspect that the old standby of Admiralty bronze or something similar is back. The racekit GSXR750 heads of the first gen motors had bronze seats - and very nice to work with too.
30 degree seat angles too - the old is new again.....
I'm a little dubious about the stem coatings - do you really need to maintain a film there ? Most bike 4V engines have very marginal stem lubrication - and live quite happily too. Any roughness will simply cut the guide out PDQ - In my experience anyway.
Remember those valves are air operated. likely piss all oil gets near them.
Pretty sure the blurb said 2% Be on the seats, not sure about the rest i only skimmed it.
Actually it might be in the Q&A afterwards.The beryllium-copper alloy used for valve seats has less than 2% Be content. With 2% Be or less the alloy still has good thermal conductivity, plus it also has a good CTE match with the aluminum head material, good mechanical strength, and is compatible in contact with a titanium valve face.
Seen this which might interest flet and Ken
I always wondered how they did itCosworth used a pressure cast process, but I think it was implemented some time after Brian's head was made. I don't know much about the process, as I worked out of Northampton and Wellingborough. I do know however the alloy was pretty secretive and impossible to de-burr by machine, and were done by hand.
John
John, they did surely, it was pressurized into a zircon coated steel tool. This was mainly for mass production though, allowing faster cycle times and therefore reduced porosity due to upped pressures.
This then saved having to make new sand moulds for each shot, just spray tool with wash when open and away you go. Temperature can be also controlled locally via coolant channels, providing chilled areas to thicker sections.
Sand cores for coolant galleries still need manual placement within tool though as with current mass produced cylinder heads
Same coated steel dies by the sound of it
that zeconium is available a PVD like ti nitride
http://www.pvdcoatings.net/faq
so i guess it blocks the heat and resists losing the steel.
Kinky is using a feather. Perverted is using the whole chicken
I still think it's heavily etched and ground, - but I have often been wrong - I accept that!
Strokers Galore!
Kinky is using a feather. Perverted is using the whole chicken
No idea on the MV. I note reading further on in that F1 thread that they're now interposing finger followers between cam and bucket. Those are apparently angle faced and the cams plain parallel. That head certainly looks like parallel buckets - but apparently not so.
That guy's foundry book when it comes out will be worth reading...
If you stick with 2 strokes,none of that complicated "valve stuff" is needed!!
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