Returning My G3C to 350cc

[RichardS]

Just for background interest

http://www.lathes.co.uk/smartbrown/page5.html

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http://www.lathes.co.uk/sabel/

[RichardS]

I'd never thought of there being different piston clearances for ally and iron barrels... the ally barrel has a pretty substantial core of what I assume to be iron, will it not behave the same with respect differential expansion between the bore and the piston as an iron barrel?
The chart also gives some typical values for piston ovality... it appears to me more at the at the crown end.

I agree, I in all likelihood the liner in mine has moved a tad, there is no ally to combustion gas interface, the liner is let within the width of the iron core. I understand a head gasket was not used originally on the ally barrel, the head and barrel were lapped together. I have tried that a couple of times but with little long term success and have fitted gaskets.

Your barrel is evidently rather different to mine which has an iron liner pressed directly into the alloy muff. I have an Alfin barrel as well and that's the same.

My biggest concern now with yours is that if it moves further it could get to a point where the top ring jumps over the top of the liner bring proceedings to a very abrupt halt - I have had it happen and it's not a lot of fun.

[Joker_Bones]

Your barrel is evidently rather different to mine which has an iron liner pressed directly into the alloy muff. I have an Alfin barrel as well and that's the same.

It may be different... but I thought the ally muff was bonded on by being cast around the iron core, that is the description of the Al-Fin process in this article.

alfin.jpg

The full article is here:
http://yorkshireferret.blogspot.com/201 ... speed.html

I would like to know more can find little on the subject.

[RichardS]

Steve,
sorry I may inadvertantly have been misleading. By saying the Alfin barrel was "the same" I meant that the iron liner fits directly into the alloy muff, but yes, you are right it is cast-in, not pressed in.

Secondly by "as well" I meant I have two barrels, one standard AMC one with (I believe) a pressed-in liner and a second AlFin one with, I assume, a cast-in liner.

Is your barrel an Alfin type? That would explain how your slipped replacement liner does not expose any alloy wall to combusion flame.

[SPRIDDLER]

More info here.........

Al Fin cylinders 1958.jpg

[Joker_Bones]

According to one of those online calculators $60 in 1958 is $630 in today's money... Hmmm thought it would have been more.
£60 in 1958 is £1400 in today's money... I'm not quite sure what that tells us.

[Joker_Bones]

Is your barrel an Alfin type?

Good question...
When I got the long stroke engine with an Al-fin barrel that I have been working on I looked at any photos I could find trying to understand the difference between an Al-fin barrel and a non Al-fin ally barrel and what models they were fitted to.
Some long stroke ally barrels have Wellworthy Al-fin and the patent numbers cast in. Others have just Al-fin and the patent numbers, others just the patent numbers and some nothing at all.
Are the ones that have no identification not Al-Fin?

When speaking to Steve Surbey at AMC classic spares he said that the factory fitted ally barrels were all Wellworthy/Al-Fin... Well I think that's what he said, or that's how I understood it, so don't quote me on that.

The barrel I have with a liner fitted is a short stroke ally barrel with the cast in push rod tunnels.
I've not seen any short stroke ally barrels with Wellworthy/Al-fin identification... But had assumed they were.

If anyone knows... Please chip in.

[RichardS]

Hi Steve,
$60 in 1959 was a pretty exotic price tag, 'though I recall my father referring to 5/- as 'a dollar' so the exchange rate was rather different from now which pretty much acount for the difference.

I am wondering now whether I have got a very confused understanding of the sources of parts. The 'original' cylinders I have have Patent numbers cast in the base (but no name or brand) and through bolts from top to bottom. None of the patent numbers come up in any search I have looked at so what they are and who they were owned by I can't say.
I assumed these barrels had pressed-in liners, but I have no actual evidence to prove or justify that.

The cylinder I have with a flanged base to directly replace a cast iron cylinder is the only one that is branded AlFin which is why I perhaps wrongly believed the others are not.

[Joker_Bones]

Not sure where you you got Steve from, I'm Russell...

Yes... I'm finding it difficult to get the full picture when you can only find snippets of information from here and there.

This is the long stroke ally barrel I have with through studs.

IMG_20230829_214356~2.jpg

Patents as per article.

patents.jpg

Other examples.

IMG_20230829_174033.jpg

IMG_20230829_173857.jpg

IMG_20230829_173739.jpg

Yes... I have come across the flanged Al-fin barrel, described as an aftermarket non-factory fitment.

[SPRIDDLER]

If you use the forum Search facility with 'Alfin' as the search term you'll find 8 pages of threads with discussions and photos of the 350 Alfin/alloy cylinder (very popular back in the day for Trials conversions) including some photos showing the patent numbers cast in the base.

(JB was posting his reply at exactly the same time as I was so some points duplicated in our posts but I'll leave my post anyway).

Here's just one of many threads found using the 'Search' facility:

viewtopic.php?t=29218&hilit=Alfin

and here's just one of many photos....

Alfin cylinder.JPG