Submitted by bsheridan@rest… on Tue, 09/29/2009 - 11:53

Can anyone tell what year XK120 Engine# F3638-8S belongs to? I recently purchased the engine and the seller said it came out of a 1953 X120 Coupe. My 1953 XK120 OTS Engine# is W8550-8. What is the difference between an "F" and "W" engine? And what does the "S" on the engine number mean?

Thanks in advance...

Submitted by rldsims@bellso… on Sat, 10/17/2009 - 21:04

Hi Robert - my Urs Schmid book has the "F" engines starting November 1953. Deal was they ran out of "W" numbers having run the number series up to the max W9999. The "F" series started with F1001. The "S" at the end of the number is Special equipment - 3/8" lift cams, lighter flywheel...it does not mean that it had the "C" type head or H8 carbs but it could have been so equiped if the owner purchased these options.

With F1001 starting in November 53 your F-3638-8S is at the end of XK120 production in Mid 1954.

Would be good to know if your engine does have the C.7707 "C" tpye head.

regards, Richard
1953 XK120m FHC
1963 XKE OTS

Submitted by bonnettoboot@e… on Tue, 09/29/2009 - 18:20

My jan 1950 OTS has engine No. W1216-8 The F series started in late 53 up until the intro of the 140 G series. The S, I dont know, but it was generally used to indicate "special" something!