It is possible. The 880 overbore is most likely achievable in the current production model. Need to look at the 920 But, we will be concentrating on larger production runs of stock units first, after generating some cash flow from that, we may look at "trick" stuffSorry John, I meant will the cylinders be available in 880 and 920 capacity?
OK, we obviously have some people here with good manufacturing backgrounds. You are right die cast (and most likely pressure die cast) alum can be nikasil plated. But the problem is cost of tooling, as die, or pressure die cast tooling, are relatively expensive. The expense of the tooling is repaid in lowered cost of components over a large production run. Key to that statement is LARGE production run. Any of the components we are making would be extremely expensive if I were to go with die casting. We just to not make large enough quantities to extrapolate the cost of the tooling across short production runs. So for short run production of complex components (like heads) we use sand casting. The cost of patterns and core boxes is much less expensive than die casting. We have been able to reduce costs of pattern and core box fabrication by 3D printing of the patterns and core boxes. In the production of cylinders, we have found that with modern CNC tooling and programming, we can make a cylinder out of billet as efficiently as sand casting the product, with the additional feature of not needing to put liners in the cylinder, that would have to put on sand cast cylindersThe underlying word there is cast. If Manley barrels are sand cast as opposed to die cast, then it would be unsuitable for Nicasil coating. More than one manufacturer has made lots of alloy barrels that are Nicasil coated, Yamaha watercooled TZ s for instance.
Thanks Knut, I appreciate the information.By using vacuum casting and an optimized fluidity of the molten alloy, porosity can be reduced to a degree allowing the surface to be plated. One well-know manufacturer of race engines has used this procedure for almost 30 years with good results. The two main parameters are degree of vacuum in the vacuum box, and the casting temperature. Lost foam casting should not be used. Of non-permanent molds, best results are obtained by using green sand or CO2 bonded sand molds. Mahle, who developed the Nicasil process, proposes their own alloy Mahle 124V (AlSi12MgCuNi) which they claim is particularly suited for casting finned cylinders of air-cooled engines. This alloy has very good fluidity according to Mahle. The alloy is heat treatable and posesses good strength and stiffness at elevated temperatures. Pouring temperature is 770-790 degrees C ( 1520--1450 'F).
This company standard shows that some porosity is acceptable for Nicasil coating.
https://www.weber-automotive.com/fi...tive/20060609_wan_zg_0002_porenklassen_en.pdf
-Knut
Wasn't it like the Alfin cylinders for trumpets ??It is also possible to cast around liners. Mercedes did this (possibly still do but I can’t be sure). They cast in a special alloy liner into the V6 and V8 sand cast alloy blocks (for petrol engines). However, a lot of R&D work would be needed to try and copy the process, so not practicable for this topic.
Wasn't it like the Alfin cylinders for trumpets ??
Thanks Knut, I appreciate the information.
G81 Can Cycle, you are to be applauded by all Commando owners, really great work. I would love to see a video of you setting up the patterns for the head casting. Any chance?Two new projects. 5 axis machining of new billet aluminum 850 cylinders. And first batch of raw castings (flashing not removed, and deburred) for first run of 850 Full Auto headsView attachment 15543 View attachment 15544 View attachment 15545
I don’t get that article. Nikasil is used in countless engines all over the world. I suspect something else was amiss with this (Ford) engine.
And I don’t buy the ‘cooler running’ argument either...
Thanks for the information. I will discuss this issue with the company that does the Nikasil work. My experience with Nikasil is on my race bikes, and it has worked well, but I do use high grade racing fuel for these bikes. But, I believe Nikasil is widely used on many sport bikes today, without major problems. Your suggestions of a disclaimer about using high Sulphur fuels may be a good ideaI suppose a stiff warning that the warranty is void if high sulfur fuel is used and if it has been it would be very obvious.