Hello Wonderful People,
As a couple of you know I'm now the proud owner of TWO Cylinder Heads - one good one and one not so good....

My question is;
Both of them have had a Black Silicone/Mastic type sealant applied to the 'D' shaped seals at the end of the Camshaft channels - is this 'normal' and should I do it to my new seals when I rebuild the Head..??
If it had been done to only one i'd have thought 'bodge' and that someone had re-used the seals but for both of them to have it....??

Your thoughts would be appreciated.

Cheers, Dave.

 

Hi Dave,

Yes, that is normal and correct to apply RTV silicone sealant to those "half-moon" plugs that seal the openings created when the camshaft journals are machined. The last time I checked you could still purchase the Jaguar factory Workshop Manual on DVD-ROM from the Jaguar Daimler Heritage Trust (jaguarheritage.com), and you can download a mostly-complete U.K. edition of the Haynes manual here:

Haynes Jaguar XJ40 Repair Manual

Cheers,

Don

 

Don,
Many thanks for the info.

I shall arm myself with a Workshop Manual and then hopefully stop asking simple questions ( I can't guarantee that last bit though...)

Cheers, Dave.

 

Hi Dave,

One of the great things about this forum is that members don't mind answering simple questions, so don't hesitate to ask.

Cheers,

Don

 

Well, I've now got myself a Haynes Manual for it - I found it in a second hand bookshop,,,,
I don't believe in fate but what are the odds on that...???

To be honest I'm a little bit disappointed with it. It's more of a Service Manual. I understand why - the Jag is such a complex machine that a manual that covers everything would be a Very big book indeed.....

Which brings me neatly to this (I can't find the answer in my new book );
Cam Chain Tensioner - I've taken the one from my old head and whilst holding it in my hand it squirted a stream of oil out of a little hole all over my shirt....
and then it came apart.
It seems to be composed of two main parts; The outer sleeve and the inner tensioner but I can't for the life of me see how it works.

As always, any info greatly appreciated...

Cheers, Dave.

 

Hi Dave,

The Haynes manual is not a Jaguar publication - it is a third-party abbreviated service manual that covers the most common repairs. It is mostly reliable with a few known errors, such as the assembly order of the transmission mount parts. As I mentioned, the last time I checked the Jaguar factory workshop manual and other documents (Electrical Guide, Parts Lists, etc.) were available on DVD-ROM from the Jaguar Daimler Heritage Trust (jaguarheritage.com).

Regarding the timing chain tensioner, I'm fairly certain Haynes explains how to reinstall the tensioner, probably in the chapter on engine service / timing chain work.

Here's the exploded view of the upper tensioner from jaguarclassicparts.com. It's a good idea to replace the O-rings before reassembly:




Here's the exploded view of the lower tensioner:


Cheers,

Don

 

Hey Don,
You're quite correct - it is in the Haynes book. Apologies.
While 'i'm on a roll' though - was there any difference in the Camshaft manufacturing process..??

My Cams in the original head (1991) look different to the ones in the replacement head although the codes are the same (EAC 9165 PB). They also have a lot more digits stamped into the casting. The Inlet cam has the following;
EAC 9165, lobe, PB, then a lobe or two, then 2, lobe, 5, lobe, F, lobe, M, lobe, 67, lobe, N, lobe, LYDI

The Cams from the replacement head just have;
EAC9165PB, then a couple of lobes, then 10, then a couple of lobes then what I think is a 'C'.
These Cams also look a lot 'rougher' between the lobes with a lot of areas where it looks like the casting Flash has been removed.

I shall try and photograph what I mean....

 

Cam from replacement head (possibly older..??). Evidence of grinding between Lobes and much less info.


Original Cam (91my). Much cleaner between the lobes and more info (whatever it means).

 

Hi Dave,

I don't know the answer, but I would assume that the cam with the PB at the end of the part number was of later manufacture than your original one. Do you have the engine number of the spare cylinder head to compare to yours? That may tell you something.

Cheers,

Don

 

Thanks Don.
I don't know the engine number that the replacement Head has come from.
My original Cams do look to be manufactured better - somehow.

I've posted my Cam conundrum in the 'General' forum as I suppose there might be an AJ6 expert elsewhere...??

Once again, Many Thanks.
Dave.