I'm now thinking they must be as rare as Unicorn poo, as on that auction site they go for what seems silly money. A NOS one went for £385.00 recently. I have a fellow BSAOC member who owns an Engineering Company, who is looking into having a pattern made to produce a batch..
So my question is :- Would there be any interest from forum members here?

email (option): ian(at)integsci.com

There is a nice used one for sale on ebay at the moment.

Henk

email (option): ahum@quicknet.nl

email (option): as per first post

I've just spent a small fortune getting my alloy head refurbished (hydroblasted, fins repaired, CR raised, skimmed, etc) so the option of buying a 'new' head would have been very desirable. Having said that I'm rapt with the quality of the work done by Basil and Stuart of Headworks in Murrumbeena, Victoria.

I guess it all depends on the price of the new heads but I'm pretty sure there would be quite a few of us from the BSA Motorcycle Owners Assoc in Melbourne who would be interested.

email (option): njgreen@bigpond.net.au

email (option): as per first post

If you can find somwhre that extrudes aluminium gas bottles, the front & back ends of the estrusion billet make perfect feed for machining single cylinder heads from.
When I mwas ay Simmetal I libberated quite a few for such a purpose.
They are of course the wrong type of alloy for casting but Al-Mn-Mg-Cu machines reasonably well.

email (option): wariron@tpg,com,au

I got mine from Henk many years ago, and they are rare all right, but maybe if you will find about 10 friends over here that are interested, it is logical to cast some new heads according to a good shaped iron one?

email (option): michasteinmann@gmail.com

The iron head and the alloy head aren't the same casting...The alloy head has more material around and between the bolt holes on the 'thin side of the head...

This is to compensate for the weaker properties of the aluminium material and is the reason 10 'long' head bolts are needed for the alloy head, not 5 long and 5 short...

What would be required as a 'pattern' is a suitably prepared aluminium head...Ian

email (option): ian@wright52.plus.com

The contraction rate for aluminium is 9/32" in 12"...or put another way approx. 1 in 42...

So a 42" long casting would contract on cooling by approx. 1"...

On a head cast off an original therefore, shrinkage isn't really an issue...

After repairing any damaged fins and bead blasting the head all over, all machined faces should have a machining allowance of approx. 3/16" of an inch added to them during the preparation of the casting.

Plywood is fine for this purpose and easily worked...For the head gasket face, for example, cut a piece that conforms to the edge of the combustion chamber and the outer limits of the machined face....

After shaping, sand this smooth and araldite it to the gasket face...repeat the process with each head bolt hole boss, the spark plug hole and the timing plug hole...These will be pretty easy to remove after the casting has been completed to recover the head for use...

Inside the combustion chamber fill the spark plug hole and timing plug hole flush to the combustion chamber face with beeswax...Again, this can be simply removed afterwards with a light application of heat to melt the wax.

The head can then be sprayed with a few coats of filler primer which should be smoothed back wherever it can be accessed...This will give a smoother surface to ease withdrawal from the sand mould....Ian

email (option): ian@wright52.plus.com

Hi Ian
Having been a pattern maker and run our own aluminium foundry for the past 47 years I can tell you that the contraction rate for cast aluminium is 1/77(imperial) or 1/80 (metric) or 0.013" per inch. 1/42 is approaching the steel contractions.
regards Jon

Why not use a 3d printer to make the pattern and it's size could be altered to allow for the shrinkage

email (option): davmax@ntlworld.com

Thanks for the correction Jon...That's what happens when you rely on memory for something you are only occasionally involved in....I should have known better...I have all the contraction rules in my workshop and the info. in a book on the subject..

Are you still running that foundry?....Ian

email (option): ian@wright52.plus.com

Thanks for the vote of confidence John...Nobody gets it right all the time but I already knew that.....

A relatively minor error though, that doesn't affect the remainder of the information in the post about preparation of the head for casting and doesn't alter the fact that contraction isn't too much of an issue when casting off an original part such as an M20 head.....

and though I certainly don't consider myself an 'expert' I 'hold my end up' generally I think....What will it be next?... Spelling mistakes? ...Ian

email (option): ian@wright52.plus.com

It\'s not a major problem, but it\'s always better to check technical information is correct before posting!
Also, I note that you are \'trade\', (Ark Motorcycles?),perhaps it would be a good idea for this to be made clear to everyone after your name.
This should equally apply to all other traders on the site.

I'm retired actually, and have been for some time...I was 'Ark Motorcycles'....

I now remain involved primarily as a reflection of my personal interest and the fact I am an enthusiast. I try to share the knowledge I have gleaned after 40 years involved with these bikes and do that freely...

My immediate reply to Jon acknowledges my error and notes that 'I should have known better' and checked my information. I don't think any further comment is warranted

My personal view is that my status, or anyone elses, is irrelevant to the inputs made to this forum...

After all this is a forum open to all and sundry....I don't think anyone has a secret agenda that they need to declare...You're not a solicitor waiting for someone to say they've had a crash so you can get in touch are you?....I guess probably not...

Nobody needs to 'beware' of my 'expertise' or lack of it....I know I have helped a lot of people to short cut the learning curve that we are all on and will continue to do so despite pointless crtiticism from some quarters...Ian

email (option): ian@wright52.plus.com

Hang on a minute John. What difference does it make to information given, whether you are a trader or not? I was a trader for 30 years (sand and gravel actually) But I buy and sell odd motorcycle parts and get a few rare parts made for people since I retired. Should I declare all this every time I make a post.
I notice however that you remain slightly anonymous. Ron

email (option): ronpier@talk21.com

Ian I don't think it makes any difference weather you or any one who posts on this site are or were "trade". Its the shared knowledge that is important. I wonder why this John has bought it up, has he an axe to grind.

Ron,I think you're missing the point...........

email (option): john.werner@bundespost.de

So what is the point exactly?...Ian

email (option): ian@wright52.plus.com

Does it matter if Ian is in the trade or has been in the trade. I'm sure I'd like to take information from someone who is in the trade or was in the trade who presumably has a lot of experience and from someone who is still enthusiastic enough to share their knowledge. What's the problem?

email (option): davmax@ntlworld.com

So, does anyone want some nice new shiny cylinder heads?

John -

Who are you, exactly? I have been tremendously helped by this "trader" on numerous occasions. He is most kind, considerate, helpful beyond measure. If you are/were a consistent observer on this forum then you would already know this and not condescend.

Again I say, who are you and what is your business here?

Bruce Cooper
Houston

email (option): btcoop77069@aol.com

email (option): t.j.walker@btinternet.com

Now i am at it, I have used both cast alloy and cast iron heads in the past, all for solo road use. I have used both for long distances over a few years. I cannot see any advantages over the cast iron head in the UK. Maybe if you are dragging a large sidecar about or riding overseas in extreme heat maybe the alloy head would be an advantage. But in the UK with a well set up engine i cannot see the advantage for the cast alloy head apart from a bit of weight saving.

Tim W

email (option): t.j.walker@btinternet.com

The cheerful help provided to all who post here won me over years ago. I went from a Gold Star snob to a WM20 enthusiast because of Ian, Ron Pier, Dave Plumb, Henk, Rik and many others. This is the best old bike forum on the planet, and I will defend the site and its principals as long as I can still shout.

How about Dave Plumb finding a trove of valuable old parts and offering them to us at fair prices rather than flogging them on eBay? And Robb Nortier buying 4 US WM20's last year and offering to the chaps on the list at cost? Ian, who developed the pistons for the 720cc WM20 and advised me on every step of my project? Trade? Try free and honest advice to all who enquire here!

Jeff Bandola

email (option): jjbandoo@aol.com

Many years ago on the Brit - iron web list ( predates forums ) we got into this sort of debate.
Now i would like to point out that any one who posts on a list is just a bunch of electrons wizzining around in cyber space and as such no one ever should be taken as gospel truth.
Now for all I know 90% of you could be cleaners at a local primary school goofing off with the governments computers and is reality it matters not who some one is, or what some one is , was or will be.
All that matters is what gets posted is factually correct
I do try to check every thing I post and where I have not preceed it with ( from memory ) and where found to be wrong I try to go back in and correct my post after acknowledging who ever corrected me.
Putting credentials down is always a BAD IDEA as it inferrs that this poster knows what they are takling about & should not be questioned, thus it styfels debate and changes an open forum where every ones views should have equal weight to a technical lecture. And then who is going to police the credentials ? Dose the fact I have a degerr & 5 post grad diplomas mean any thing? Or is in fact the former a bold faced lie to make me sound impostant ? How many people on the list actually know who I am ? Does it really matter ?
now Ian did acknowledge his corrector which is the proper thing to do & I am sure he will go back in and edit his post with the correct data ( hint ) which is all one could & should be expected to do

email (option): wariron@tpg,com,au

email (option): ian(at)integsci.com

come on chaps call a truce, were here for the beer , not the fight,I enjoy my hobby and keep my business out of this , (nothing to do with WD bikes)but should the subject remotely come up will maybe put my two p in , am on hols off to futurescope today, enjoy yours, andrew

email (option): warbikes@gmale, (think about this)

This is silly...
Ian is known to everybody here, and he is one
(If not the most, without insulting anyone else of the good and appreciated contributors..)
Important contributor to the forum, and was always prepared to happily help anyone hare or off-line,
And share his vast knowledge.. Ian never hid his trade, and when thinking of manufacturing
GOOD parts, to the benefit of all, he always checked here openly if it is needed, providing the specifications,
The price it will go for, and the expected date of availability, so no secrets at all..

People can sell on this forum whatever they like, traders or not, and believe me, Johan,
That solicitors and scammers are being exposed here in seconds, and all members are warned.

Ian, keep on being wonderful !

Noam.

email (option): noam10@gmail.com

Ian, i hope for a quick recovery of you.
I also disagree with John, but on the other hand, everybody is allowed his own opinion.

Back to the cil heads; if i remember well there was an article in the Classic Motorcycle a few years ago about a guy who had an AJS v -twin without (proper) heads. He made them himself one way or another.
So it shouldn't be to difficult.

Thank you for all the support from forum contributors on this one...I really appreciate your kind words...

It is great that you all show a real determination to support the values and attitudes that are prevalent on this site (an on no other I have seen)

Very rarely does an open forum function and 'self police' so effectively...I think that reflects the fact that many of us have become friends both on and off the forum and we really do respect each others knowledge...and there is a huge amount of it available here from all quarters...

I have to say personal criticism is scarce on the forum and long may it remain so...there is nothing to be gained from that other than bad feeling...

I feel I've made my views plain in my own defence and think most of you know them anyway, so I plan to say no more on the subject this time....Back to bikes.... ...Ian

email (option): ian@wright52.plus.com

This guy has repro Todd heads for bsa bantams, not much difference between making / casting them and M20 heads.

http://www.ebay.co.uk/itm/361024233584?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT


Price is reasonable too if you have someone with a machine shop to do the work , I reckon you should be able sell alloy M20 heads unmachined for around the £125.00 and £250.00 machined ready to fit.I suppose it all depends on how many you have cast to get the price right?

Hi Dave,


It looks nice, and if the material is correct,
It's really good, but I wonder why he chose to hide the bottom part-
(The combustion chamber) and show virtually 3 identical photos of the top...

Noam.

email (option): noam10@gmail.com

Noam...He probably doesn't want people welding up their 'ordinary' Bantam heads to recreate the Todd format...

Dave...The factors involved in repro parts are always the same as it's not viable to make large quantities and thus gain the benefits of volume production...

You have to manufacture the part in a relatively small quantity but at a good quality and at a price that you can sell it at, once you have applied a sensible profit to make your effort and investment worthwhile...

That is a relatively difficult equation, take it from me...

You also have to be mindful of the fact that if you get any of those things wrong you might end up with less money than you started with and a lifetimes supply of something you don't need....

So, it's best to do your sums carefully and and spend some time considering the price the market will accept and just what the demand might be for the finished product...Then you're ready to take a chance... ..Ian

email (option): ian@wright52.plus.com

...I took a look at the Bantam head and see it's unmachined...

So you don't have a Todd head at all but a lump of finned aluminium...

Unless you are conversant with the exact dimensions of the Todd heads it would seem to me you are going to have trouble recreating anything with this....

I suspect that having priced up the machining work he's decided it might be better just to sell the blank casting at a lower cost....Ian

email (option): ian@wright52.plus.com

Ian Wright I didn't know you were Ark Motorcycles. I don't care really cause your a champion in my book. I have been watching this forum for as long as I can remember ( many years) and you always contribute far beyond anyone. Your information is always very informative and I take notice of everything you say.
Your slight slip up in this case wasn't really important, the point was shrinkage wouldn't matter. Everyone on this forum for any length of time knows who you are and what you are all about. If any information is critical then we all know you will give the correct specifications etc at the time.
I just want to say thanks very much. I for one really appreciate your effort. I don't know that this forum would be the success that it is without your contribution. It may have still been a good forum but it definitely wouldn't be the same.
cheers mate

Thanks Terry...I'm glad you have found the information on the forum so useful and appreciate your comments...

This isn't a 'one man show' though...far from it...

There are many here who make a contribution based on the particular knowledge they have and the sum of it all adds up to what the forum is....An amazing concentration of accumulated knowledge...

I know little for example, of contract dates, factory records etc. etc. or anything beyond a limited knowledge of all the detailed changes made and when, exactly, they were introduced..

Also, my knowledge is very much focused on the technical side of BSAs primarily...

However, all this and more is covered and there is rarely a question for which someone doesn't have an answer...

I know I have learnt a lot from the forum myself over the years and am frequently amazed at the stuff people know...

I've had a few incorrect assumptions put right as well!... ..Ian

email (option): ian@wright52.plus.com

While the high Aussie $ might make expost a bit dear, there are a lot of foundries down in Victoria & SA that will be activly looking for new markets now that all the car makers are closing shop so it might work well if some of the "southerners" have a quick word with a local foundry as they might be willing to do a batch and carry the can themselves as part of exploring new product lines.

No good me looking at Sydney foundries as most closed down with the Rail way workshop ans AFAIK only 3 left.
Shore process will make perfect castings but they will be way too dear and theother two do mainly decorative work.

Alloy should be straight 12.5 % Si sand casting aluminium

email (option): wariron@tpg,com,au