JowettTalk

Now that many modern cars have aluminium heads, albeit with steel inserts for the valves, is it time for someone to attempt this for Javelin or Jupiter?

The casting technology exists, and aluminium easier to cast than steel, the materials are now of a quality that aluminium can be relied on to do the job - indeed engines with much greater pressure than the post war Jowett engines are sucessfully using it, and the weight gain surely would be significant.

Anyone ever tried such a thing? Perhaps this would be something of interest to those racing cars, having lifted and moved an awful lot of heads in the last couple of years it must be possible to shave the best part of 10kg off the weight of the car through this. No idea what implication for regulations on racing, but once painted I can't imagine a scrutineer getting a magnet out to check, but anything is possible!

My initial thoughts on problems with this were that a frame or other support would be necessary to ensure even pressure across the head - the aluminium would probably have a lot more flex than the standard, and some reinforcement would probably be required around the head bolt holes, but otherwise it might be worth a crack surely?

Jack.

I'm pretty sure that alloy heads have been made way back for javelin/Jupiter engine. Not absolutely sure but I have a recollection of seeing a pair in Ken (not Roy) Bradocks premises in Marple in the seventies.

george

Jack, I have also seen a set of aluminium cylinder heads in the past, but as I remember they were the OHC set that someone made up back in the 50's for the Jupiter but never finished and fitted to an engine. When I saw them circa 1969, they were owned by Ian Dearie as I recall.

Having heads made in aluminium is obviously entirely possible (I suggest that you contact Paul Fricker at Granger & Worrall; he can tell you what is involved), but I would recommend that while externally the heads may want to be nominally indistinguishable from the original item, all possible technical improvements should be incorporated internally. This probably eliminates thoughts of OHC architecture, but features from current Detroit 2-valve heads would seem appropriate. I would be surprised if new AL heads were any less rigid than the feeble Jowett cylinder block/crankcase.

Philip

I saw a pair of aluminium (double overhead cam) heads fitted on a Jav/Jup engine earlier this year! They are owned by ex-JCCA member Joe Caudo in South Australia, but unfortunately, the engine is not yet running. It is still in the development stage with several "issues" to be resolved before it can be run. I believe that Joe has owned the heads for about 15 years. They were designed & manufactured by S.O. Hodge, who also built replica standard bodies for 5 Jupiters in Sydney NSW. Joe also owns the famous Wylie Javelin open-wheeler GP car built in 1952 that runs a supercharged Javelin engine. Best wishes to all for the New Year,

Andrew Henshall
JCCA Victorian State Representative

Andrew Henshall wrote:I saw a pair of aluminium (double overhead cam) heads fitted on a Jav/Jup engine earlier this year! They are owned by ex-JCCA member Joe Caudo in South Australia, but unfortunately, the engine is not yet running. It is still in the development stage with several "issues" to be resolved before it can be run. I believe that Joe has owned the heads for about 15 years. They were designed & manufactured by S.O. Hodge, who also built replica standard bodies for 5 Jupiters in Sydney NSW.

DSC04435_c.jpg

Best wishes to all for the New Year,

Andrew Henshall
JCCA Victorian State Representative

Hi Andrew,

I was thinking about a very similar casting to the steel one, but that is something else. Wow. Can we get some more details on the heads and engine build? That looks, well, utterly bonkers, and as a result very interesting I am sure that many people would be interested to see some more detail in the Jowetteer on this, it would certainly generate some debate and fulfil the desire for more technical articles and information.

Jack.

do they reduce the turning circle to around 100ft!

george

Jack,

I don't have any more technical info about the DOHC heads, and knowing how busy Joe is, I suggest we shouldn't hold our breaths waiting for more to become available! I'm writing the history of the Wylie Javelin for publication by the JCCA, and await additional info from Joe on his historic open-wheeler; I have to be patient as he has a couple of large businesses to run. I did hear that he was going to take the Wylie Javelin to Mallala Raceway SA for a test session late in 2013 and was thinking of attending, but couldn't find out when it was.

I understand that Joe purchased the DOHC heads from Tim Hocking of Brisbane, but don't know how Tim came to own them.

George,

The quad-cam engine is no wider than a standard Javelin engine, and should fit into a Jupiter without causing any significant restriction in steering lock. Don't know about a Javelin though. If Joe is able to resolve the remaining issues and get the engine running, no doubt it will be fitted to his Targa Tasmania Jupiter to be fully sorted.

Regards,

Andrew

I am assuming that these - and other - heads are castings, which of course involves tricky - and therefore expensive - mould tools for the cores as well as the outer forms.

Has any thought been given to the possibility of producing them in two parts, similar to the way I understand some Marendez heads were made?

This could eliminate the casting problems and possibly give rise to a CNC programme that could be easily 'exported' to other places where CNC facilities exist.

Apparently there are no insurmountable problems with water sealing the two parts, and the part exposed to the cylinder/valves is all one piece.

Any comments?

Ian,
Other than Marendaz in the thirties, has anyone else used that split construction that you know of? It seems relatively simple and straightforward, but as you like to point out, the devil is in the details.

I have done a sketch of the present Jowett cylinder head [below] showing the approximate locations of the internal inlet and exhaust tracts, and using that as an example I have shown where the split-line might be placed. In one case, it is right down the centerline, and in the other case it is perpendicular to the valve axis which would permit the valve guides to be used as assembly dowels. Either way the split will pass through the port tracts and while I can see that sealing the outer perimeter of the head from water leakage would be quite simple, sealing the port tracts would be much more of a development challenge given the temperature variations on the exhaust side. There may also be a challenge in machining the water gallery underneath the port runners. Of course, if this concept is applied to a new, non-Jowett head design, then it may be possible to design around these issues.



Philip

Philip (et al),

There was an article on this in The Automobile a few months back. Unfortunately I am away from home at the moment but I will try to trace it when I get back. Unless of course someone else gets there first (to the magazine I mean!).

From memory, the front cover related to Marendez, but I am not sure.

We shall see.