Speedex Heads

[Alan]

For me, the LRM mk2, except it was cast out of milk bottle tops or something. But it depends what you are doing. There are compression heads and breathing heads. If you want low down torque you need compression. If you want high revs it needs to breathe. A’37 head with 60 thou off and sharp edges removed takes a bit of beating.

[Ian Williams]

Alan, sorry to be pedantic but in one of your posts you referred to the 9E heads as being the same design to the 37 heads, I would argue against this statement. The combustion chamber and plug placement of the 9E, reproduction or not, is noticeably different to a 37 head, I agree however that other than the improved plug position reducing fouling issues little noticeable performance is to be gained with the 9E. I agree to that the LRM head is a good one, mine worked well but did not last long! The problem is that many of our opinions are somewhat subjective unless someone were to dyno a whole range of the options out there on the same engine we don't know for sure, then there are all the other variables, cam, valves, manifolds etc which come into the equation.

[Steve kay]

This makes interesting reading, but for this simple soul leaves some unresolved questions. I put a hc head on my Ruby but it made such an increaed racket that I soon put the lc head back on. I was worried that the noise was from the bottom end, but one contributor suggests pistons rather than bearings. The head is marked 1A911 and AF2, whatever that says about its origins. I am aware of how much gas flow contributes to performance as the first tuning on my 2CV were Pete Sparrow gas flowed heads making an immediate and noticeable improvement. So the question is does a Dave Dyer head improve gas flow or raise compression?  Speed is not important for shopping or nav rallies, reliabilty is paramount. Unthreatening performance improvement is always desireable however.

[Alan]

Ian, re 9E heads, that’s not what I meant- 9E is different to ‘37. It’s some Cambridge heads that are similar to ‘37, but then some are copies of 9E too b

[Steve Jones]

In another thread on the same subject, someone mentioned the 1980's 9E casting in bronze. A good head and Malcolm has one. However, any performance advantage is, probably, negated by the weight of the things. It takes two of you to lift it!!

Steve

[Ian Williams]

I see Alan that makes sense, however the 9E copies that I have encountered all have virtually identical combustion chambers to an original 9E in my possession. To help clarify this for readers, I have an Alan Raeburn Alloy version from the 80's, which is a very good quality heat treated LM25 casting. I believe Paul Bonewell had the patterns after Alan died and was casting these up until quite recently, certainly a friend of mine purchased one from him about 5 years ago and the quality of that was comparable with the one I own. I also have one of the Cast Iron copy's that Tony Betts was selling until quite recently, another friend also uses one of these and we both have had good results with them. Over the years I have experience of Silvertop, Ricardo, Speedex and LRM, as well as modified 37' and LC heads, in all honesty, with exception of the LC, differences are pretty marginal, but all better are I believe than std unmodified heads. With the amount of positive feedback around Dave Dye's Ricardo heads I would suggest they are probably one of, if not the best option currently available

[Mike Costigan]

... The head is marked 1A911 and AF2, whatever that says about its origins...

The 1A911 is the part number and differentiates it from other Austin cylinder head designs; the AF2 merely signifies it was manufactured in Austin Foundry number 2.

[Adam Brown]

Are you plannng to race the Van, Adam?

A rethink on the future of the Hamblin Special. Visiting Brooklands on Sunday has left a desire to go and have a play, something that isn't 100% fair on the Chummy.

The idea is to modify the special to fit the VSCC. I don't want to win races (or indeed race), I just want to have a car that can take part and do ok for the joy of competing.

We'll keep the old body and the Speedex head for the future, I'll probably go down the Riciardo route as suggested. I had wanted to do it up as a pukka 50's special but it will certainly see more use if it can go to VSCC events and there are other family members who may be tempted to have a go at such things.

[Malcolm Parker]

My experience of the Dave Dye Ricardo head is the fitting of them to mildly tuned engines, not out and out racing engines.  The SWB saloon has been fitted with a Ruby head, a wedge planed early head, a bronze Raeburn 9E1 head and latterly the Ricardo head over the 20 years it has been on the road.  The Ricardo head is by far the best.  The engine is quieter, smoother and much more responsive, especially at the lower end.  The engine has larger (Mini) inlet valves which probably didn't suit some of the other heads used. Standard cam with flattened followers.
I opted for the 18mm plugs as they look more vintage and seem to be less prone to fouling.  I generally use old spark plugs, some must be 50 years old, they seem to work better than new ones! Being from Yorkshire you will understand my philosophy.

[geoffharrison]

On a lighter note - my 35+year old motor mower has a 3.5 hp Briggs and Stratton side valve engine .
The combustion chamber is very similar to the late iron head but with a trough on the exhaust side .
Surprisingly the larger inlet valve opens BTDC with the exhaust still open .
A drop of Castrol R in with the petrol and its a pleasure cutting the grass .

One of the slight advantages of either the Whatmough or Ricardo heads is the improved water flow over the length of
the head , not just through a slot at the front as with the iron heads .