Speedex Heads

[Tony Press]

From memory wasn't the so called '37 head' an unlicensed Ricardo type ?

[Austin in the Shed]

In my case, Tom, 'out of the box' (although they don't come in a box - at least mine never have!). Dave's probably the best to comment about the potential for any modification. They're all numbered and dated. My latest version, bought in July last year is number 272. There's a lot of them around!

Steve

Compared to the original head I machine the valve area  and guarantee it will clear up to a 1.2" dia inlet valve with 5 /16" lift. I have reduced the turbulence step in the combustion chamber and raised the compression ratio to around 6 3/4 : 1.
The Ricardo is a 1920's design to use with the  fuel quality of the time.
They take nearly 4 hours to machine conventionally ,dress,inspect and pressure test.

[Tom Coates]

Some of you might be interested in some flowrate measurements I did a while back. These are all on a tuned block with 1.125 in inlet valves, and compares 37 Head with Ricardo and 9E at increasing valve lift. This was measured at a vacuum of 24inH2O and is corrrected for temperature and atmospheric pressure.

Interesting, this seems to confirm the view that there is a trade-off between compression and gas flow, although the ricardo head appears to flow better than the 9E for the same CC volume. Out of interest, was the rest of the inlet tract modified? There aren’t many people willing to share this type of information for A7’s.

[Alan]

Tom, yes the block is ported and the cylinder edge relieved. For me, the important thing apart from the comparison was the fact that the ‘37 head choked at about 0.25 in lift. The restriction was not the valve opening it was the transfer from valve chamber to cylinder. Once this was resolved I have a head with higher compression than a Ricardo, but which flows like a ,37. Can you see a picture? No chance.

[dickie65]

Heady Stuff This !!!

[Jack in the Box]

This is a very interesting thread. Can anyone point me to any historical documents confirming the involvement of Ricardo in the A7 head design? I ask this as an ex Ricardo employee who has so far not been able to find a link. Thanks Alan

[Austin in the Shed]

Do you mean the Ricardo head ,Alan or the late ruby design ?
Ricardo's own head is covered by the patent no on the head,Registered in 1929.

[Alan]

There is quite a bit in the Proceeds of the Institute of Mechanical Engineers, but not specific to Austin Sevens. However, I don’t know how it worked in the 1920s but these days if a manufacturer pays a consultant to do some design work, the contract probably forbids disclosure.

[Austin in the Shed]

Ricardo did combustion chamber design for many manufacturers in including Rolls Royce .Even Lister diesels I believe.

[Jack in the Box]

Dave,
I was thinking Austin production, so I suppose I mean the late Ruby.
A couple of years ago I met the late David Morgan at Beaulieu and, after a chat, I agreed to try and find out more about Ricardo involvement with A7's. I managed to access the correspondence file between Austin and Ricardo but could find no reference to head design. I sensed that the engineers at Austin were not very receptive to having Ricardo involved at all.
If it's no bother, would you let me know the patent number on the Ricardo head please, then I'll try and find out if it relates to generic design principles rather than A7 specifically?
Thanks Alan