The head gasket evolution as I know it.
The first one was E1ADKN-6051. From early 53 (and I just can't find a serial no. for it) E1ADKN-6051B replaced the original gasket. Both of these were copper asbestos but don't really know the difference. From the fitting of the engine to the Thames ET6 many changes occurred, the petrol engine had the compression ratio increased to 6.4 to 1 for the lorry. Tractors remained at 5.5 to 1 but used the same head, with two E1ADKN-6051B head gaskets and a spacer E6-CA-9 between them (not too clear about this, if anyone has more information it'll help get this right). Then from 1425097 the steel gasket (E1ADDN-6051B) replaced the previous E1ADKN-6051B on diesel engines. The Mk2 types have a new bypass hole and a slightly different rear end. The petrol compression ratio remained unchanged but I don't know what happened to the gasket. At the same time the 6 cylinder engine appeared, the original gaskets being 508E-6051 and 510E-6051. From 1481091 the petrol compression ratio was changed to 5.84 to 1 on tractors with new gaskets E1ADN-6051 and spacer E7-CA-9, the lorry remained unchanged (the new parts were offered for Mk2 engines as well). From 1518654 a new Copper asbestos permanite gasket (E1ADDN-6051C) was fitted to solve the issues with the steel gasket. This coincided wit the large diameter spigot liners and the new locating dowels. At the same time 510E-6051B catered for the same change in the 6 cylinder engine (not sure about this but would make sense, if anyone can confirm this it will be appreciated). For service E1ADDN-6051D and (510E-6051C) were provided for engines originally fitted with the steel gasket. Finally from 1565580 the final composition gasket was fitted (E1ADDN-6051E), together with smaller diameter spigot liners. This change also happened on the 6 cylinder engine, being 510E-6051D (not sure about this either but again would make sense, if anyone can confirm this it will be appreciated). I'm not sure what was done to petrol engines but the parts book quotes 953E-6051 for zero octane use (and presumably TVO engines for service). Ebro probably started with the steel gasket then followed a similar evolution but went onto their own S1ADDN-6051C still with flat liners. They carried on with flat liners and put a composition gasket on in 66 or so (S1ADDN-6051D). The last number I've found is S1ADDN-6051F, it looks like another steel gasket but don't really know, there's very poor information on this and no idea how many changes occurred.
Now for a table (missing details will be filled in as they're clarified, Ebro serial numbers are not at all clear yet so for now won't appear, Mk1 industrials (954E, 955E, 956E, 562E & 563E) are also similarly unclear as are many lorry numbers, especially ET6's):
Part no. _________________________ use
E1ADKN-6051 _________________ 1217101-Early 53
E1ADKN-6051B ________________ Early 53-1425097 & 500E-0001-500E-46804
E1ADDN-6051B ________________ 1425097-1518654, 530E-0001-approx 530E-12775 & S0001-(between S160725 and S162216)
508E-6051 ____________________ 508E-0001-508E- & S0001-approx S616139 Equivalent to 1425097-(08D-976148)
510E-6051 ____________________ 510E-0001-approx 510E-75130 & S0001-(between S160725 and S162216) Equivalent to 1425097-1518654
E1ADN-6051 __________________ 1481091-, 528E- & S
E1ADDN-6051C ________________ 1518654-1565580, approx 530E-12775-approx 530E-19291 & (between S160725 and S162216)-aprox S200000
510E-6051B ___________________ approx 510E-29813-approx 510E-52550 & (between S160725 and S162216)-aprox S200000 Equivalent to
_____________________________________________________________________________________________1518654-1565580
E1ADDN-6051D ________________ Service for E1ADDN-6051B
510E-6051C ___________________ Service for E1ADDN-6051B
E1ADDN-6051E ________________ 1565580-08D-976148, approx 530E-19291- & aprox S200000-approx S752487, Ebro made until approx S900000
____________________________________________________________________________________________don't know if this was used
510E-6051D ___________________ approx 510E-52550- & aprox S200000-approx S616139 Equivalent to 1565580-(08D-976148)
953E-6051 ____________________ Service on zero octane and TVO
S1ADDN-6051C ________________ Early Ebro production
S1ADDN-6051D ________________ Mid Ebro production
S1ADDN-6051F ________________ Late Ebro production
And now for pics (please add any you can, lorry and industrial engines are also):
E1ADKN-6051
E1ADKN-6051B
E1ADDN-6051B
508E-6051
510E-6051
E1ADN-6051
E1ADDN-6051C
510E-6051B
E1ADDN-6051D
510E-6051C
E1ADDN-6051E
510E-6051D
953E-6051
S1ADDN-6051C Super Billy's gasket just after removal, will get better pics when I can
S1ADDN-6051D
S1ADDN-6051F
Note the post is unfinished as I only have access to our vehicles, therefore your help with pics of the other heads is highly appreciated. I have seen some on Ebay, causing some doubts on where the part no. and EnFo (or FoMoCo) are stamped. Also Ebro parts are rather more difficult to keep track of with no proper manuals around.
Note at the time of posting I don't yet have good pics of our ones, they will come shortly.
Sandy
