Triumph iron head year

[tractorman]

I have a cast iron Triumph head, I believe 6T. It has recesses around the combustion chamber, so fits a spigotted barrel. However, the oil drain arrangements from the separate valve chambers are via drilling through to the joint face of the head to the barrel. The head has been cast with lugs that are normally drilled to take the oil drain via pipes to the pushrod tubes, but these have not been drilled ! unforunately I do not have a barrel with drilled oilways., was this a special casting or can the "normal" barrel be drilled?
I had a look at various parts lists and note that 6T barrel was spigotted in 1958 and flat in1960, but the books indicates that in both these years external drain pipes were used
so what year was it? and are there any decent books that catalogue detailed changes with early Triumphs?

[Welsh Wizard]

Hi not sure but in 1950 the 650 had drillings , before that I think the casting was blank, any chance of some pictures if the offending head.

[tractorman]

Hi Welsh Wizard, 3 no. pics attached, you can see the undrilled bosses, and the oilway drilling angles, hope this inspires more responses

[Martin_UK]

Looks like a 1946-47 500cc head with the internal oil drains ? Whats the casting number by the plughole E2258 ?

Regards,

Martin

[Welsh Wizard]

I tend to agree with Martin looks like a 46 head to me as well

[tractorman]

thanks guys.

no casting number anywhere that I can see

I assumed it was 6T  as it was lose on my 5T barrels. The head combustion chamber recess measures 2.845" and my 5T barrel spigot has an OD of 2.680". So I now assume the 1946 barrel must have wider spigots

So, this 1946 oil drain system, was a failed experiment? Its much more tidy, than the external pipes, perhaps the drillings were difficult? not enough meat in the barrel casting? I would be interested to learn more

[Welsh Wizard]

in april 1956 the spigot hieght was reduced from 3/16 to 1/8  ref service sheet 153 Triumph, may be worth checking the height of the spigot.