Cylinder head aluminium v Iron

[dickie65]

I have run a standard Nippy Head, modified Ruby Head, and now use a Ricardo head as its the smoothest running head,
The Nippy head makes the engine harsh.
I tried a Whatmough Hewitt head but it would not fit over the valves both in diameter and lift without grinding work.
So for me its the Ricardo Head that works best on my engine which is a 2500 to 7000 engine that will not tickover under 1000rpm
Its in a road car used for speed hillclimbs.

[Bob Culver]

All else equal, alloy heads enabled higher cr before pinging became a problem. (on the likes of sv V8 about 1 ratio advantage) On a Seven with either material breathing considerations limit cr to below where pinging becomes a problem. Heat loss from the combustion can be less with iron.
Iron heads are certainly resilient. Decades and 150000 miles ago I ran my iron head Hillman at 60 mph for miles dry . Added water boiled 15 minutes later! No effect. The same engine with alloy head was notorious for blown gaskets.

[Parazine]

I've always suspected the folklore about the tendency to oil plugs comes from the days when the standard of engine rebuilding was "it'll do"

It isn't folklore at all. I had an engine in my first, 1928 Chummy which went like stink but if held up, with a partially open throttle, the 14mm plugs on the HC head would oil instantaneously. 

I managed to get a set of Cord rings (the block was +0.060, gas flowed, big valves and cracked), fitted them and all was well for 10,000 miles. Then the oiling started again.

Eventually, I opened out the plug holes and re-tapped for 18mm plugs. Problem solved and with the 1A911 number removed the eligibility scrutineer would have been happy too!

[Alan]

I agree with Charles.

[Henry Harris]

I've not managed to find a picture of the combustion chamber of the Dave Dye 'Ricardo' cylinder head. 
Can anyone post a picture? 
Thanks

[Austin in the Shed]

    New Ricardo next to a used 9E reproduction.
The combustion chamber volume usually works out around 26cc.
The step was designed to create swirl ,Ricardo claimed to be able to run two compression ratios higher without knocking.

[Bob Culver]

For the same c.r is the 9E inferior? The step around the inlet valve perimeter sems curiously placed.
The 18mm heads were remarkably resistant to oiling. At one stage my car burned about a pint ih 40 miles of hot main road running. After a long descent, following traffic was competely obliterated but never missed. A 1937 head burning about a pint in 300 miles and on leaded petrol would sometimes miss one or two beats on pick up. Did not experiment with plugs.

[Austin in the Shed]

Never tried a back to back with a 9E Bob,but against a modified late Ruby head on a dyno gave 3 bhp I am told.This from someone who has had several Ricardo pattern heads.I don't think he would have bought more than one  if they didn't work.
I don't know of another A7 head with plugs fitted on the inlet side but Ford ,Harley Davidson ,Douglas,and Jowett did.
I did try putting 10mm plugs (Racing plugs) down the priming cock holes (On the inlet side) in an early head,It did 1500 miles on an oily engine and the plugs were clean still when the head was removed,and they had never been cleaned.
This head was disappointing considering it was skimmed to the max for a std lift cam and the old plug holes were plugged and profiled inside the combustion chamber.Put this down to poor transfer flow to the cylinders.

[dickie65]

Hi I have tried a 9E head and the Ricardo head on the same engine.
I found the Ricardo head made the engine much smoother.
I think the smoothness is down to combustion chamber position the 9E fires over the valves and gas expansion pushes more onto one side of the crown causing the piston to tip and wobble.
The Ricardo combustion is more biased over the piston crown.
My engine attains higher revs with the Ricardo Head too.
The car has never been on a dyno so I can not quote relative power figures ( I do have an 8000 rpm electric Tacho instead of a fuel gauge )

[Rogerfrench]

Dickie, I find that to be a curious conclusion. Are you sure your 9E doesn't have too high a compression ratio? Did you do a pipette test?