T & T cylinder head

[Robert Leigh]

Reading this thread reminds me of my ignorance about the various cylinder heads. Is the T&T head the same as the Dave Dye head (they look very similar)? It seems strange that the pictures of actual heads differ from the Ricardo patent drawing, in having restricted space over the inlet valve rather than the exhaust. Has anyone come across a head made in the style of the Ricardo drawing? Do any exist in this form? I have always used standard '37 type Austin heads, but I have occasionally wondered if the right aluminium head with its different design could be better, but if so which one?

[Bob Culver]

Other makes have modest trenches to the inlet valve. With modern octane the plug position possibly matters little but the crowding of the inlet must.

[Nigel Ricardo]

May I suggest you contact Ricardo PLC at Bridge Works, Shoreham by Sea, they have a very extensive library on Harry's work,so should have the patent number there.

[Austin in the Shed]

Front page of the patent application

[Henry Harris]

There seem to be two Ricardo Patent Specifications relevant to the side valve Austin Seven 

148046  1919/20  Covers the later Ruby head and those made by other major manufacturers, some under licence, some not.

The original 4 page document can be found here.....,https://worldwide.espacenet.com/patent/s...%20ricardo


309092  1927/29  This is what T & T were supposedly using. I wonder how much royalty they paid unnecessarily!

As yet I haven't found any other manufacturer using this design. 

The original 22 page document can be found here.....https://worldwide.espacenet.com/patent/s...%20ricardo

[Bob Culver]

T and T should have paid no royalties used in reverse form! I suspect Alans explanation is correct!

[Austin in the Shed]

I don't claim to understand the tech in the patent documents but surely to "Create turbulence in the charge" would need the step on the inlet side as to cause turbulence as the gas passes over the step?
Did Ricardo get Thompson and Taylor to produce the heads,or did T and T produce them as their own venture ?

[Zetomagneto]

Hi Dave, I have 2 of your heads and perfectly happy with them but can now see they are not what is shown in the patent drawing. The T&T ones are obviously not in accord with the patent.
Turbulence, or squish can be produced by having a very tight clearance between the piston crown
and the flat portion of the head, this head has that capability. Squish clearance no more than .020”.

[Alan]

The interesting thing about this is T&T/ Ricardo heads clearly work. There’s loads of dynamometer results to prove that. Now, apparently Harry Ricardo was not the worlds best at publishing test results. I wonder if something caused him to change his mind. I really can’t believe it’s a mistake.

[geoffharrison]

Alan , I've just dusted down my 1931 copy of Ricardo's ' The Internal Combustion Engine ' . A complete chapter is devoted to 
' Influence of form of Combustion Chamber ' and the ' Shock Absorber ' Head as he called it is detailed , with test results etc., . 
The pocket can be over either the inlet or exhaust valve and the spark plug over either valve , depending on what rate of burning you want to achieve. He also states that ' although the sparking plug is no longer centrally situated , the 'Shock Absorber ' type of head is very slightly better than the ordinary turbulent head '
Personally I think the very similar Whatmough - Hewitt patent combustion chamber is an improved design due to the chamber shape.  
As I run one of each type of head I'm not too biased . 
I will bring the book along at the first convenient Bert Hadley .
Geoff.,