Up until this weekend I was aware of 3 styles of cylinder head fitted to ES2, 19R/S, 50 during the fifties. Circa 1950 it was still the iron head. Around 1955, possibly a little earlier, there was the Al-fin head. This was the same shape as the iron head but with an iron skull combustion chamber and aluminium fins. It used the same rocker box as the iron head. From 1957 there was a new version of the aluminium head with cast-in pushrod tunnels.
At the Stafford show I noticed a head for sale which at first glance appeared to be the Al-fin style. On closer inspection there were no Wellworthy Al-fin markings visible in the casting. There was a much smaller iron insert, extending only to the valve seats and spark plug hole. Everything else, including the recess for the cylinder spigot, being aluminium.
Just for curiosity, does anyone know when this version of the head was used?
Aluminium head
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Thanks Richard
After posting the query it crossed my mind that 500T might be a possible candidate, but until spotting the head for sale at Stafford I had never seen one.
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Aluminium head
Hi Ian and Barry,
I'm fairly sure Barry's head is the early type. If you look at the bottom fin area you can see it has been turned down so the head recess fits the Model 19 barrel spigot. This is 1/4" in depth where-as the early 500T barrel has a 3/8" spigot the same as the cast iron ES2. This is a bit academic as everything else will fit O.K.
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Hi Ian,
The head you describe is from an early 500T. These were fitted from late 1948 until some time in 1950 or early '51. These were sand cast and have a rougher surface than the later Al-fin die cast heads which replaced them. The iron insert in the early heads looks like a pair of spectacles and some people refer to the heads by that description. The Al-fin heads were probably cheaper and quicker to cast than the early type and were identical to the heads used for the 1955 season.