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Interesting Article

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SumpMagnet:
so is he saying that casting other than die-casting is always brittle asnd full of air bubbles......

I always thought that pressure die-casting was for complex shapes where the metal would tend not to flow into all the corners under gravity alone, not to prevent air bubbles.

curious as to how well informed he is about metallurgy....as I am not buying his expertise on Hondas

K2-K6:
He seems to be confusing various elements each with another and then placing odd reasoning on top of crap foundations to delude himself.  How could you trust him to judge (as his other writings say) to advise people on purchase of anything really.  Looks wholly unreliable as a scource.

Specifically,  seems to be confusing mould type with pressure or no pressure method of casting.

Speaks as if it was the first engine Honda had cast,  with no experience before this  :)

Crankcase "drilled" as obviously not heard of line boring  ;D and understand what this entails. 

Sadly lacking in very fundamental knowledge.

MCTID:
AFAIK the early Sandcast engines were Sandcast because Honda had no idea whether they would sell or not and Sandcast moulds are much cheaper than tooling up a Die casting Production Line.....especially on a Prototype machine (and don't forget how revolutionary the K0 was back in 1969....or 1967/8) when Prototypes were probably first being made, where you might need to make a series of modifications following the Trials of the finished machine - AND the finished Engine Castings......when you had figured out the relevant parameters influencing machinability, tooling, access for servicing, longevity, strength, scrappage rates (of the castings) etc etc.   

Die Casting was certainly a much better, cheaper - per part produced, faster and reliable (repeatable) process than Sandcasting and ensured that complex changes of cross sections and lengthy (relatively speaking) chambers needing to be properly filled with molten alloy were sound......perfect for a CB750 engine, which compared to my Triumph cases from the 60's makes them look positively agricultural !

In this article he fails to mention that if or when a Sandcast engine blew up....the only Service replacement available would have been a Die Cast engine as once the Die Casting Production line was up and running, Honda wouldn't make any more cases using the Sandcast method.

In a past life I was involved in specifying/ testing/ inspecting castings of all shapes, sizes and complexity and part of the 'Contract' with the Foundries was 'how expensive the patterns/ moulds/ dies were to produce; how long would they last (i.e. how many pieces would they make before they required reworking - or scrapping) and whether we (the Buyer) wanted to pay for them outright and own them (so we could take them to another Foundry if this one didn't perform) or whether we wanted to pay for them via an extra charge on each casting produced'.

flatfour:
Didn't MV Augusta use sandcasting for all of their engines up until at least the late 1970's?

Surely, if there was a fundamental problem with this process for engine component production they would have used an alternative?

SteveD CB500K0:
MV probably never planned on Honda volume (or wore out their dies)


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