XK120SE question

[427James]

Hello all,

I have been looking at a '54 XK120SE. The cylinder head is from an XK150 but apart from that the numbers match. Anyone got any idea as to what this will do for the value of the car and whether its worth taking it on as a project (the "E" (last project) is closing on being finished).

[RichB]

Not a Jaguar chap, I'm into 50s Astons however I imagine the principles are the same and if as you say the chassis and block match I can't imagine a replacement head would make any difference to the value at all.

[427James]

427James said:

Hello all,

I have been looking at a '54 XK120SE. The cylinder head is from an XK150 but apart from that the numbers match. Anyone got any idea as to what this will do for the value of the car and whether its worth taking it on as a project (the "E" (last project) is closing on being finished).

Thanks Rich. I am trying not to let heart rule head on this one, but seriously think I will go for it.

[RichB]

Put it this way, people often talk about having the original block denoted by the engine number but I've never heard anyone talk about he cylinder head number, if indeed it has one.

[a8hex]

In the case of earlier XK engines then the head number is much more visible, in fact you can hardly miss it. The block number would be down on the side whereas the head number is on the back of the where the head comes up to cover the cam shaft drive sprockets, at the front of the spark plug valley.
The lack of the correct head will have an effect on the value, but I wouldn't have thought it was that much unless you are trying to concours the car, but lots of people modify XK120's anyway (disc front brakes, pedal box extensions, 5 speed boxes...) so it would depend on how much originality the buyer was after.
The XK150 head is a "B" type head, so rather more efficient than the original one. The 120 could be ordered with the "C" type head (not to be mistaken for the head of a C-Type), but the B head gives the same power but with a much broader torque spread.
XKs are wonderful. I'd go and enjoy it.

[427James]

a8hex said:

In the case of earlier XK engines then the head number is much more visible, in fact you can hardly miss it. The block number would be down on the side whereas the head number is on the back of the where the head comes up to cover the cam shaft drive sprockets, at the front of the spark plug valley.
The lack of the correct head will have an effect on the value, but I wouldn't have thought it was that much unless you are trying to concours the car, but lots of people modify XK120's anyway (disc front brakes, pedal box extensions, 5 speed boxes...) so it would depend on how much originality the buyer was after.
The XK150 head is a "B" type head, so rather more efficient than the original one. The 120 could be ordered with the "C" type head (not to be mistaken for the head of a C-Type), but the B head gives the same power but with a much broader torque spread.
XKs are wonderful. I'd go and enjoy it.

Thanks - you are of course correct - the head no is easy to read, the block no, a PITA to find. Thanks for all the responses and interesting to hear about the B type head.

[jith]

a8hex said:

In the case of earlier XK engines then the head number is much more visible, in fact you can hardly miss it. The block number would be down on the side whereas the head number is on the back of the where the head comes up to cover the cam shaft drive sprockets, at the front of the spark plug valley.
The lack of the correct head will have an effect on the value, but I wouldn't have thought it was that much unless you are trying to concours the car, but lots of people modify XK120's anyway (disc front brakes, pedal box extensions, 5 speed boxes...) so it would depend on how much originality the buyer was after.
The XK150 head is a "B" type head, so rather more efficient than the original one. The 120 could be ordered with the "C" type head (not to be mistaken for the head of a C-Type), but the B head gives the same power but with a much broader torque spread.
XKs are wonderful. I'd go and enjoy it.

That is actually the engine number a8. You can tell that by the fact that the last number on it will be a /8 or /9 to denote the compression ratio. It will also tell you if the head has been changed as the number will not match that of the block.

J

[a8hex]

jith said:

a8hex said:

In the case of earlier XK engines then the head number is much more visible, in fact you can hardly miss it. The block number would be down on the side whereas the head number is on the back of the where the head comes up to cover the cam shaft drive sprockets, at the front of the spark plug valley.
The lack of the correct head will have an effect on the value, but I wouldn't have thought it was that much unless you are trying to concours the car, but lots of people modify XK120's anyway (disc front brakes, pedal box extensions, 5 speed boxes...) so it would depend on how much originality the buyer was after.
The XK150 head is a "B" type head, so rather more efficient than the original one. The 120 could be ordered with the "C" type head (not to be mistaken for the head of a C-Type), but the B head gives the same power but with a much broader torque spread.
XKs are wonderful. I'd go and enjoy it.

That is actually the engine number a8. You can tell that by the fact that the last number on it will be a /8 or /9 to denote the compression ratio. It will also tell you if the head has been changed as the number will not match that of the block.

J

Thanks Jith I should have been clearer, the head number the block number should of course match. But in the case of my 150 the block was original but the head wasn't, at some point in its life the head was replaced with one from a MkVIII. Heads get replaced more than blocks. I've an original XK150 3.4 head from a car not too far away from mine sitting on the shelf. If I ever get my original engine rebuilt then I'll see whether it makes sense to have it rebuilt with the other 150 head, still won't be matching number, but it'll be closer :-)

[RichB]

So Jag put the same number of on the block and head? Life's easier with the Feltham Aston engines, I don't think the head's numbered. I'd love to see some of these Pistonheader's XKs some time, lovely cars and if I hadn't gone down the DB2 route I could have been tempted

[Edmundo2]

Friend of my dad had one of these years ago. Unfortunately he passed away a few years ago and I believe the car was auctioned. I clearly remember that it was a special equipment model and had c type cams. Don't know much about them so unsure whether all SE's featured these sorts of performance upgrades or whether it was modded etc. enjoy it if you buy!

Edited by Edmundo2 on Friday 2nd August 21:31

[redchina]

There was a 54 XK120SE FHC RHD for sale in Octane Sep 07 for 60k GBP, brgreen.
(ex Nigel Dawes if this helps?)
1 of 6 allegedly.

that might help your price appraisal a little? was being sold by Specialized (sic) vehicle solutions in Manchester.