Hi all :
Yesterday we had our Yearly swap meet and club meeting.
I bought there a low cyl. head. At home I find out that the thread of the plugs is 18 mm and not 1/2 ". They don't use adapters .
Do you know when this head was made and for what reason ????
Thanks in advance .
Toon

Anthonie,
You do not want to trust me completely on this one. However, I believe that I have read on this forum several times that for several years the heads were made in the USA for shipping to England and Europe to use the 18mm plugs which were much more common "over there".
I believe that is a very nice, and proper, model T engine head cast on February 27 (the 2 27 cast into the rear of the head) of an unknown year between 1913 and 1917. It looks like a wonderful find!

But, as I say, hopefully someone a bit more sure of their facts can chime in here.
Drive carefully, and enjoy, W2

I thought I posted something -- but I don't see it. This is just a check to see if it is working.

Respectfully testing,

Hap l9l5 cut off

(2nd try)

Anthonie,

Nice find!

From: http://www.mtfca.com/encyclo/E.htm#eng3 it verifies the date range for the Made in USA added to the head and the introduction of the high head. Since the date on the casting of your head is Feb and that was not added until Apr 1912 at the soonest (probably took some time to phase it into production) your head could not be a 1912. So 1913- to 1917 dates Wayne shared are correct.

04-16-12 T401C Added "Made in U.S.A."

05-17-17 T401C Redesigned — High Head — Changes ASAP, Use Up Old Stock.

From page 510 of Bruce McCalley’s (R.I.P.) book “Model T Ford” he has the following comment:
Note in the records that follow: LH = Left hand; RH = Right hand; LHM = Left hand metric; and RHM = Right hand metric. “Metric” means the spark plug holes were metric thread, for overseas shipment.”

Note starting in 1915 the actual engine production logs are available and on Jan 8, 1915 eight RHM engines are listed as being produced. The first entry for LHM was 38 engines on Jan 28, 1915 (page 510). Those entries continued through Dec 1919 (page 522). The Metric threaded heads on the engines would have be produced before 1915 but the engine production logs are not available before Jan 1915.

Perhaps someone has some additional information that would indicate when the metric spark plug heads were first available. The first documentation I found is the shipping record for car #13,300 which was manufactured Dec 3 1909. It was a green RHD, metric spark plug, touring shipped to Scotland (ref page 485 of Bruce’s book).

Respectfully submitted,

Hap l9l5 cut off

Wayne and Hap :
Thanks for your answer.
Toon