Speedex Heads

[Steve kay]

The things one learns on a Wednesday morning, many thanks Mike! Now, does the part no indicate any Ricardo influence in gas flow, or merely raised compression ratio?

[Dave Wortley]

I have Speedex heads on 2 Sevens. Been trying to look at Dave Armstrong's Speedex site to check on compression ratio for the head but no success so far. Any clues please?

[Steve Jones]

A lot of us have tried a lot of heads over a lot of years. I've become a firm convert to Dave's repro Ricardo heads currently having four of my five engines fitted with them. If you were to have a look at cars that are competing be it trials, race or speed I think you'll find that a majority these days are fitted with this head. Of course, that might just be a case of following a fashion but, surely, we can't all be wrong.

Steve

[Ian McGowan]

Having run the scrutineering at the Northern Filter for the last Welsh w/e I can endorse Steve's statement. 90% of trials cars passing through had Dave Dye's Ricardo heads. (somewhat to my surprise!!)

[Tom Coates]

Steve and others with Ricardo heads, did you fit them "out of the box" or modify the combustion chambers? Whilst the overal quality of the castings is excellent I thought there was probably scope to sfound off the sharp edges and generally polish things up a bit, but I'm not sure whether this is worth the effort.

[geoffharrison]

A lot of us have tried a lot of heads over a lot of years. I've become a firm convert to Dave's repro Ricardo heads currently having four of my five engines fitted with them. If you were to have a look at cars that are competing be it trials, race or speed I think you'll find that a majority these days are fitted with this head. Of course, that might just be a case of following a fashion but, surely, we can't all be wrong. 

Steve

I'm obviously not a follower of fashion as I've been using a Whatmough head for about 20 years !
Although one engine does have one of Dave's Ricardo heads .
Geoff

[Steve Jones]

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

[Alan]

I have a Ricardo head on my RL. The Chummy has a standard head, modified a little. The special, a 9E, and the Ulster a very modified Whatmough. Impossible to say which is the best as they all do different things. However the Ricardo does fit straight out of the box. The Whatmough doesn’t.

[JonE]

the other brilliant thing about the Whatmough and Ricardo is that you have one less water joint to worry about!

[Alan]

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.