3rd time lucky?

[Wilder]

Well they say 3rd time is a charm... I have now been offered this head to put in place of the S3 head currently sitting atop my S2 E type 4.2 long block.
Its amazing what you can learn in a week, but I don`t begin to claim any degree of knowlege compared to the members here.
I hope someone may confirm what head this is, or likely to be from, and that it is in essence, the same head as my E type S2 should have....I was told that it is the right one (heard that before...)
I know its a long block head, due to the extra water holes at the rear, and I believe it is at the earliest a 1968 head due to the ribbed cam covers (which I think came in around 1968).
The head is not numbered, so I will take a guess at a 420G...But what do I know?
Its never been skimmed, and the cams are in situ though you cannot really see in these photos.
The engine man says it will restore nicely, providing its the right one this time!

[Tom W]

Looks good. It looks like it has the central rectangular cutouts to clear the hot air feed across the engine on US spec cars. According to the JCNA guide, that would make it the 3rd variant of S2 engine. The changes seem to relate to carbs and intake on US spec cars. I don’t know if uk spec cars also got covers with the rectangular cutouts, despite not having the hot air feed. Maybe the JCNA guide can help with identifying it.

https://www.jcna.com/sites/default/file ... pe2(2).pdf

[johnetype]

I can't read the label with red writing on the inside front of the exhaust camshaft cover but if it talks about clearances being 12/14 thou and it's the original cam cover for that head then you have a head that is later than your engine.

It would be good to have a photo of the cams and see if there is a hole in the back of the lobes.

[mgcjag]

C2537 is from a S1 xj6 for engine numbers 7Lxxxx.....S2 E type will be C26202 or C28391.. (knowledge base S2 parts catalogue)....As mentioned before the part number is the key.....Steve

[mgcjag]

Rectangular slots on top of cam covers were used on US spec cars with emmission eqp but became standard even on UK cars from engine No 7R8768 and 7R38895.....Steve
On ebay now C2537 xj6 head https://www.ebay.co.uk/itm/jaguar-xj6-4 ... ect=mobile

[Paul71a]

I can confirm that even uk S2 cars had the cutouts. My May 1970 UK car has them.

[Wilder]

Thanks guys, that is interesting feedback.
I believe the early S1 is a comparable head, along with the 420G ( ie it was basically the same head), and that can be used to replace the incorrect XJ6 S3 head that is currently fitted, and it will look correct.
I need to let the engine guy know on Monday if we can crack on with this head or not.
I am guessing that from the comments, that the concensus is in the affirmative..
I was told the correct S1 head to substitute for the S2 E type, was up to 7L1175, but that information means little to me I`m afraid.

[mgcjag]

Hi Jonathan you replied in a previous post to me when i sugested you keep the S3 head... "I take the point Steve, but its a question of honesty and integrity.
I cannot offer a fully restored car for sale if it is not "original" in terms of the major "period components".
If you do this, then where do you draw the line?"....so why now are you considering a S1 XJ6 head instead of an E type one with the correct part number.....Steve

[Wilder]

Hi Jonathan you replied in a previous post to me when i sugested you keep the S3 head... "I take the point Steve, but its a question of honesty and integrity.
I cannot offer a fully restored car for sale if it is not "original" in terms of the major "period components".
If you do this, then where do you draw the line?"....so why now are you considering a S1 XJ6 head instead of an E type one with the correct part number.....Steve

What I meant Steve was this I believe,is a near identical head, apart from the stamped number on it, where as the other was 20 years newer and from a completely different model...

[mgcjag]

Hi Jonathan....I thought your main point was to restor and then advertise and sell the car "as it left the factory"...... a S1 head will not achive this and when you sell you cannot say it is..........Steve

[PeterCrespin]

Indulging in a bit of topic drift, the eBay head shows the early parabolic cams very clearly. Many know that all 4-bolt cams are parabolic (i.e. use clearances in the 12-14 thou range on both cams) but some people get confused about how to tell the 2-bolt parabolics from earlier non-parabolic cams. Jaguar differentiated the two designs by machining a groove around the circumference of the sprocket flange and the eBay photo shows this clearly.

[johnetype]

A bit more detail here:

http://www.georgiajag.com/Documents/Camshafts.html

The only thing wrong with this article is when it says 1968 it should say late 1969.

[johnetype]

From the other threads you've posted, I believe your engine is only a month or two older than mine so you need:

Ribbed camshaft covers with a cast Jaguar logo but no rectangular cutouts.

Camshafts that have a hole in the back of each lobe and require 4/6thou clearances.

The extra waterways for a long stud head.

In summary, an early S2 head. None of the three heads you've shown so far meet all these criteria so are not correct.

[MarkRado]

[chrisfell]

I’ll say this quietly, so as not to upset any purists....
Keep the S3 head. Bigger valves, parabolic cams.
Then match the ports, tune the carbs, set the ignition for 99 octane fuel and enjoy the performance.