NEW Die-cast cylinder muffs

[A_HRD]

We all know from various discussions on this forum that the original die-cast cylinder-muffs, introduced around 1954, were worse than useless being made from an inferior material that had a hardness little better than plasticine. Accordingly, they crushed and stretched inappropriately when in service causing liners to go out of round and oil to get between the two.

But I contend that there is nothing wrong with the process of 'die-casting' itself; how many of you have die-cast (Omega) pistons for example? It was an issue of poor material selection - and poor quality control thereof.

I note that some of our suppliers are offering only die-cast muffs (probably procured from Mr Holder). Does anyone have any evidence as to their suitability for purpose? In other words, are they manufactured from a tough material which does the job as well as sand-cast ones and almost as well as billet ones? Does anyone have any anecdotal evidence either way?

I only ask because I'll be in the market for a pair of new muffs and liners soon…

Peter B
Bristol, UK.
STILL WANTED: Series A Front Frame - even a twin would would suffice!

 

[Ken Tidswell]

We all know from various discussions on this forum that the original die-cast cylinder-muffs, introduced around 1954, were worse than useless being made from an inferior material that had a hardness little better than plasticine. Accordingly, they crushed and stretched inappropriately when in service causing liners to go out of round and oil to get between the two.

But I contend that there is nothing wrong with the process of 'die-casting' itself; how many of you have die-cast (Omega) pistons for example? It was an issue of poor material selection - and poor quality control thereof.

I note that some of our suppliers are offering only die-cast muffs (probably procured from Mr Holder). Does anyone have any evidence as to their suitability for purpose? In other words, are they manufactured from a tough material which does the job as well as sand-cast ones and almost as well as billet ones? Does anyone have any anecdotal evidence either way?

I only ask because I'll be in the market for a pair of new muffs and liners soon…

Peter B
Bristol, UK.
STILL WANTED: Series A Front Frame - even a twin would would suffice!

Omega pistons are not without their problems, the occasional fatigue crack due to a cold shut, has happened, Ken

 

[mercurycrest]

While we're on die-cast questions, does anyone know why Vincents decided to change over to extremely expensive die-cast molds instead of new sand-cast patterns, given the dire financial problems they were in? It would have seemed like a recipe for certain suicide to me.
Cheers, John

 

[david bowen]

Die cast was the in thing, better surface finish, less porosity, and cheaper to make in bigger batches, and made 5 miles down the road from the factory, by John Dales foundry who did most of Vincents casting

 

[mercurycrest]

Hi David,
I agree about the casting quality, but, the key words are "Bigger Batches"....... It must have cost Vincent ten times what the die-cast bikes sold for against what those dies cost to make. The likes of Ford and Honda could afford Die-casting, but Vincent? I think it was a foolhardy (stupid) move.

 

[david bowen]

The first die cast crankcases were made 1954 for the D,s JBs book, but there is no record of when the first die cast muffs were made Peter B said 1954 ,

 

[Albervin]

I seem to remember reading that Vincent ordered a lot of new equipment in 1950 to replace old worn out machines and tools. When the administrator stepped in a lot of the orders were cancelled or postponed. Could the dies have been part of the postponed order that Vincents were still committed to purchase?

 

[david bowen]

That could be the case as last casting changers were 1949, 1. C heads 2. Vincent embossed crankcases.