Is this an XK Head?

(Kevin Wiseman) #1

I recently purchased some parts for my E-Type from a gentleman who threw in what I assume to be an XJ Series 1 engine head. After some feedback from another forum, it was suggested I repost this question to this group. The code next to #6 spark plug port appears to be GZ72.

Any clues as to what model would match this head based on the code and attached photos? It appears the head was removed and had #6 intake and exhaust valves replaced and never reinstalled. #6 valves are in new condition.

IMG_6874.JPG3264x2448 2.22 MB

IMG_6871.JPG3264x2448 1.67 MB

IMG_6872.JPG3264x2448 2.25 MB

(Ian) #2

Think your find it’s a head off a 4.2 block , extra waterways at the back makes it XJ6 or E-type .

(Peter Jan Rusch) #3

As far as I know it should be indeed a XJ6 head, E-type never had the extra waterways.

Peter Jan

(Paul M. Novak) #4

Can you post a picture of the spark plug valley showing all the spark plug holes? I want to see whether or not this head was tapped for the air rail.

BTW, Jaguar numbered the cylinders on the XK engine with #1 at the firewall and #6 at the front of the engine. So what you are calling #6 is really #1.


(Roger Payne) #5

Ian is correct - the characteristic extended waterway at rear of head was introduced in Oct 1968, so for both XJ6 and Series 2 E-type from Engine No 7R1915 (FHC/OTS) and 7R35389 (2+2) onwards.

Another dating clue is Kevin does not advise any Engine Number stamping on the head as was always provided on the vertical face of the spark-plug valley up to July 1969. From July 1969 (7R6306/ 7R38106) onwards, Series 2 E-type cylinder heads no longer had any Engine No stamping - it was now on the bellhousing flange of the block only.

The GZ72 stamping is the Head Sequence Number, which also allows more accurate dating of head, but I don’t have any useable data for these later July 1969 onwards XJ6/E-type heads.


(69 FHC ) #6

Not also above the oil filter head?

(Roger Payne) #7

When the Engine Number was stamped on the Head (vertical face at front of spark plug valley), it was also stamped on the Block (on horizontal flat surface where oil-filter mounts).
When Jaguar stopped stamping Engine Number on Head from July 1969 onwards, they also stopped stamping on the Block above the oil filter head, and changed position to bellhousing flange on the exhaust-side/left-side/near-side of the Block casting.

(David Jauch) #8

Thats not necessarily important? Heads came without air injection all the way until 1992. It is a 4.2 head; you can measure the inlet valve size to rule out Series 3 XJs. Are the frost plugs in the valley plugged or bolted shut?

(69 FHC ) #9

Ah, thanks for that bit of info. That’s got to be one of the lesser discussed running changes.

(Kevin Wiseman) #10

Thanks for your replies. I can confirm that this is a non- air injected head and that there are no numbers stamped on the vertical face and the frost plugs are bolted shut. Can I assume this head could be from a post 1969 Series ll XKE or a Series I XJ?

(David Langley) #11


I have seen the point at which Jaguar ceased to stamp the engine number on the cylinder head (for the E-Types at least) put in question, whereas there does not seem to be the same question concerning when it was moved from the oil filter are to the bellhousing flange (July '69). Some assert that the cylinder head was never stamped on the Series 2s, and others suggest that the change came even earlier, when the ribbed cam covers were introduced on the 1.5s. I don’t have any documentary evidence one way or another, so I thought I’d ask if you’ve seen anything.


(Roger Payne) #12


Refer to SERVICE BULLETIN B.71 of August 1969 titled ENGINE NUMBER LOCATION - if you don’t have I can scan and post copy. It mentions XJ6 4.2, 420G, Series 2 E-type Engine Number exact demarcations.

Also if you look at the Series 2 E Type Handbook, issue E.154/3 only advises the earlier Engine Number locations on page vi, but in issue E.154/4 and later, it advises early and later Engine Number locations, but not the exact number, and to date I have not done a detailed comparison of XJ6 and 420G Handbooks.


(David Langley) #13

Thanks Roger. I checked my SBs and I don’t have B.71. I don’t want to put you to any trouble over this, so no need to scan your copy just for me. Just to be absolutely clear in my question, I am only concerned about the point at which Jaguar ceased to stamp the engine number on the cylinder head, not the location change of the cylinder block stamping. There have been several discussions in the past on the E-Type part of the forum on this topic, and from reading them it seems that (for the E-Type at least) the cylinder head stamping may have ceased in 1967 at the time of the introduction of the ribbed cam covers on the S1.5. I wonder if this might be a US only phenomenon? To date (I know that this is very unscientific) I’ve only seen reports or photos of cylinder heads WITHOUT the stamping from the E-Type ribbed-cam-cover era. The only reported such head with a cylinder head stamping was the subject of a discussion on suspect “tampering”, as the font of the stamping on the head (and the block, as I recall) were unlike Jaguar’s standard stamps. Maybe this post will trigger a number of contradictions from listers with the engine number stamped on their ribbed-cam-cover cylinder heads - it would be good to hear about such data points if they exist…


(Robert and Darlene Stevenson) #14

In 1980 I bought two E-Type parts cars, a 64OTS & a 68FHC for $800!! The cars and most of the parts are long gone but I still have the engine from the 68 and the head does not have the engine number stamped on it. I still have the commission plate and the car was 1E 35084 with engine # 7E15872. As I know nothing of the history of that car but as it was only 12 years old when I bought it I would think that it was the original head but, on the other hand, wouldn’t use it as proof of anything!

(Roger Payne) #15

OK - not so sure about the ribbed-cam cover aspect, but indeed may have something to do with the USA 1968MY package (Emissions and Safety Legislation, and how British Leyland handled that).

First up - see below a copy of Service Bulletin B.71, which as suggested really only talks about the Block stamping of Engine Number……….

But my other source of factory information is the Series 2 E-type, owners Handbook - the next scan shows page vi as in issues E.154/1 to E.154/3 of the handbook………… note, talks about both block and head engine number stamping.

Then the revised page vi for handbooks issues E.154/4 and E.154/5 now reflecting the advice as per Service Bulletin B.71, but simply as (Early Cars) and (Later Cars) without the B.71 exact Engine Numbers………

Now this is the situation I am familiar with after many yeras of looking at predominantly RHD Australian Delivered Series 2 E-types (and Series 1-1/2 E-types) that did not have of course the USA only legislated Emissions Requirements, and all the associated regulatory bureaucracy in obtaining legal entry to USA market as USA 1968 MY cars (the S1.5 cars) and then as USA 1969MY cars (the S.2 cars). So maybe the deletion of the Head Number stamping for USA cars only, was associated with the head modifications required to comply with the 1968MY emissions (and regulatory) requirements, and if so, then look for physical examples from late 1967 date-of-manufacture cars, with exact introduction point of 1968MY compliant cars being of a known Engine Number. (I do not refer to 1968MY cars as being the introduction of Series 1.5 as in Australia and other non-USA markets Series 1.5 refers to the first removal of the glass headlamp covers, which is some months earlier in 1967)

With an International Forum such as this, we need to be careful not to use parochial terminology, which starts to matter with 1968MY USA market cars and later.


(David Jauch) #16

Yes. There is a point in time when they stopped drilling the cam lobes, too, assuming the cams are original to the head you can narrow the time window. Those debating above should know.

I‘m not exactly sure when they started to use plugs instead of bolt heads. All I know for certain is that my 1984 S3 XJ has plugs and the 1971 S2 E has bolts. Must be buried somewhere, the information that is.


(Terry Sturgeon) #17

For what it’s worth my 68 ots 1E17808 built May/68 eng # 7E17289, has the short head, bolts, and no serial number stamp on the head. The block is stamped over the oil filter. Car was delivered to Germany. I’ve owned the car since 1972.