Service bulletins

I have had reason to review my holdings of the so called ‘original’ Jaguar SERVICE BULLETINS that most people believe started at BULLETIN No.1 (Dealers) of 14th August,1946, see below…

I say ‘so called’ as indeed there were some ‘earlier’ Bulletins…
There were actually three versions of BULLETIN No.1 the other two being deliberately different content for (Main Dealers) and (Distributors) both dated May 1946 which explains their respective roles in the handling of this new initiative of Service…

But of immediate interest is that many years ago when I obtained a very complete set of these earliest BULLETINS from a UK Dealership - thus the Bulletin No.1 (Dealers) as scanned above - there was included several earlier Bulletins that I can only presume was all that was available to an immediate post-war Jaguar Dealership…

The immediate earlier one was issued by Jaguar Cars and is dated April, 1946 - see below first page of 2…

My original is a 2 pages foolscap size sheets, so sorry about my A4 size scan of only page 1.

But then earlier again was a few STANDARD MOTOR Co Bulletins from 1945 and 1946, with SERVICE BULLETIN NUMBER 7 of 7th February 1946 being the last, and as shown below (again original is foolscap).

Now I only have No.3 (November 1945) to No.7 of these Standard Bulletins, but presumably there was a No.1 and No.2, and was there any later than No.7 ?

So can anyone advise/comment about anything else re Service Bulletins for Jaguar post war, and indeed was there anything at all issued/provided pre-war for SS Jaguar, noting of course the Standard relevance to 1-1/2, 2-1/2 and 3-1/2 litre SS Jaguar and Jaguar mechanicals etc.

Would love to liaise /compare notes re anything on Bulletins or other Technical Literature from 1930s and 1940s…

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Always interesting to see new information (or is it old information?)

Regarding SB1, I have the May 1st 1946 version (note it uses month/day/year format) issued to Main Dealers, and the first five paragraphs are the same, but then there are differences. This reads like a letter describing the general business policy situation, not specific servicing instructions. I note they are both professionally printed.
Several subsequent SB’s also use month/day/year format.
They were all professionally printed up through SB51 May '49, then typewritten after that.

Your April 1946 Maintenance Instructions is typed on a typewriter, and reads like what would be in an Owner’s Handbook, or like a First Service Voucher.

The Standard Motor one seems to be specific to their models, not to SS which did not have the same chassis or springs.

Thanks Rob - yes the SB1 (Main Dealers) is May 1st, 1946 whilst the SB1 (Distributors) is just May 1946, whilst the SB1 (Dealers) as pictured is of course 14th August, 1946 - I do have originals of all of these 1946 to 1959 (first series) No.1 to No.276 SERVICE BULLETINS with a few suffix A, B and Cs and reissues along the way, and indeed agree there are various printings and paper used.

AS you say No.1 to No.51 were all quality paper/printed Bulletins, and for some strange reason so was No. 79 and No.94, but many of these (maybe all) were also reprinted/reissued in typed/roneod format (No.2 is earliest I have in both papers/format), and there was clear evidence of certain Bulletins being reprinted in USA, with different size paper and indeed a few local USA references, and certain Bulletins were issued for HOME MARKET only and others for Export/Overseas markets only, so quite a challenge to put together what I like to think is a ‘complete set’, albeit who knows what else I have missed…

But my main interest this time is what/if anything was issued/used during the 1930s SS Jaguar period, and what else was issued/used post-war, before the introduction of the new Jaguar series in May/August 1946…

My STANDARD Bulletins from 1945-6 and the sole April 1946 Jaguar Bulletin suggest my set did come from one of the original Jaguar Dealerships, with the holdings of the STANDARD Bulletins stopping at No.7 suggesting obtained/issued for some Jaguar relevance, and not just something received by a Standard Dealership…, maybe a dual marque Dealership? I don’t know of anyone heavily into/knowledgeable on Standards who may be able to comment…
But given much of SS and SS Jaguars original documentation was based on Standard origins, I imagine their was diminishing relevance, but realistically Jaguar offered little themselves until 1946/7.

Thus my appeal - what else is out there… apart from the Handbooks, two simplistic Spare Parts Catalogues, a whole lot of misleading/unreliable Sales Brochures (in a technical/accuracy sense), plus of course a number of relevant/period ‘factors’ catalogues…

I waited a few days to see if anyone else would come up with anything. The fact that nobody has is in itself suggestive, that there was nothing else. I have the 1938 Instruction Book on pdf, courtesy of one of the Peters on this forum, thank you again. There were other Instruction Books issued every year or two containing information on changed parts, shock absorbers for example changed from vane type to piston type.
Then there was the infamous '38 spare tire compartment. That should have rated a bulletin, …or an apology. :laughing:
I presume you have looked through the brochures page, and I see there is a letter from SS to a garage in Exeter about plugs, valves and carbs, and saying they were going to send them an Instruction Book.
There was something called “Motor Trader Service Data” of which I have only one page.

This seems to be aimed at independent garages, as opposed to SS dealers.
But the fact that the 1946 Service Bulletin No. 1 IS No. 1 suggests to me that the whole concept of Service Bulletins was a new thing, at least for Jaguar. Otherwise they would logically have continued numbering from the pre-war set if there was anything to continue from.
Maybe there just wasn’t a great need for bulletins pre-war, or at least SS didn’t see a need.
Just the idle thoughts of an idle fellow.

BTW there is an interesting set of letters to a customer in Missouri who wanted a chassis only, to put a Hibbard town car body on it. He was refused.

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Hi Roger,

I have the Motor Trader articles published in 1951 for all three cars and they do give very useful information that I can email to you if you don’t already have them. The only pre-war information that I have is the 2½ litre owner’s handbook that does give a reasonable amount of maintenance information. Oh, I also have a copy of the 1938/39 parts list. I have a post war Standard 12/14 workshop manual and parts list that is more comprehensive than the ubiquitous Jaguar Service Manual.


I have an original copy of the Motor Trader leaflet that was in the history and paperwork with the car when I purchased it. Here are the other pages:

I’m happy to scan this document and email it as a PDF file if anyone wants a copy - just send me a personal message.

Thanks for these scans of MOTOR TRADER booklets - there is also a similar one for 2-1/2 litre as well, plus one for just SS Jaguar 2-1/2 litre and ‘100’…

My main interest (this time) however was exploring any other factory Spare Parts and/or Service Bulletins as issued prior to the August 1946 No.1 onwards Bulletin Series (later referred to as VOLUME 1)

I recently acquired a small set of SS Cars Ltd Service Bulletins that what I have range from one referred to as No.2. which I believe dates from October 1938 up to No.20 actually dated 27th February 1940. I am missing a couple, and have a couple different but showing the same No. - so was hoping someone else may have or may have seen these or similar - these ones are all single page and text only, but I do find this period factory material most interesting, but a real challenge to learn what exactly does exist… see No.15 of 3rd May 1939 attached as an example…

Excellent, Roger.
So they did restart the numbers post-war from No1.
And on that note, I find that the needles in my '38 SS 2.5 are DS, so some PO may have complained of lack of immediate pickup, and had them changed.
In fact DS is the only one listed in the '38-'47 SPC, and repeated in the '46-'48 SM.
DS is listed in the Haynes SU book under .090" jet needles.
I wonder what the previous needle was, didn’t find it in the '38 Instruction Book. The '36-'37 SPC only gives the price, 2/6.

The 2½ litre needles went through various changes.
The most obvious DS change is enrichment starting at position 3. image

RO 1936 R3 1937/48/49 2 1938/39/40 DS 1941 Position
0.089 0.089 0.089 0.089 1
0.085 0.085 0.085 0.085 2
0.081 0.0805 0.0814 0.0805 3
0.077 0.0776 0.0785 0.0776 4
0.074 0.0759 0.0767 0.0759 5
0.071 0.074 0.0749 0.074 6
0.0685 0.0722 0.0732 0.0725 7
0.066 0.0703 0.0714 0.071 8
0.0633 0.0687 0.0696 0.0695 9
0.0605 0.067 0.0678 0.068 10
0.058 0.065 0.066 0.067 11
0.0558 0.0632 0.065 0.066 12
0.053 0.064 13

For the 3½ litre:

DY 3.5 litre FL 1947/48 FW 1948-50 Position
0.089 0.089 0.089 1
0.085 0.085 0.085 2
0.079 0.079 0.081 3
0.0775 0.0765 0.0775 4
0.074 0.074 0.075 5
0.0715 0.0715 0.0725 6
0.069 0.069 0.070 7
0.0665 0.0665 0.0675 8
0.0643 0.065 0.0665 9
0.062 0.065 0.0665 10
0.061 0.065 0.0665 11
0.06 0.0665 12
0.059 0.0665 13


The 1½ litre SU needles are:

DS 1938 EH 1939 EN 1940 FA 1941 > Position
0.089 0.089 0.089 0.089 1
0.085 0.085 0.085 0.085 2
0.0805 0.082 0.0813 0.081 3
0.0776 0.0805 0.0778 0.077 4
0.0759 0.0788 0.074 0.072 5
0.074 0.0775 0.0706 0.067 6
0.0725 0.077 0.068 0.063 7
0.071 0.077 0.0657 0.06 8
0.0695 0.077 0.0643 0.0585 9
0.068 0.077 0.0632 0.0576 10
0.067 0.077 0.062 0.0567 11
0.066 0.077 0.0621 0.056 12
0.077 0.062 0.055 13

Could I have an explanation for a complete amateur please?

  1. How should you read the numbers in these tables?
  2. What should the ordinary user of Jag 3 ½ 1948 understand from that?


Perhaps only that they (Jaguar Cars) decided to very slightly enrichen the mixture with the later (1948) needle profile but only in the middle positions, when the ”throat” is half way open. :slight_smile:

By now it’s not sure if the carbs are original to the car and engine.

A dyno run would tell the AFR at various revs and possibly carb positions although it is normally done with WOT.


Hi Slawek,

Firstly, I don’t know how the tables appear if you are just looking on email. Go to the foot of the email and click on the link to take you to JagLovers forum.
The numbers are the diameter in inches of a needle at various places as shown on the needle drawing. The larger the number then the weaker the fuel/air ratio for that particular position of the needle in the jet.



Thank you!
Seems to be clear but I am still a bit confused.
@Peter_Scott “The larger the number then the weaker the fuel/air ratio”
@ptelivuo “slightly enrichen the mixture with the later (1948) needle profile but only in the middle positions”
In the table belowI read that in position 5 the diameter was 0.074 in 1947/48 and 0.075 1948-50.
The diameter/numebr is larger so the fuel/air ration is weaker and not richen.
What do I misunderstand?

Just looking at the table it would appear that there has been a progressive weakening of mixture since the SS Jaguar with its DY needles.


Thanks! Now it is clear for me.


Sorry, yes, so it seems.

I had it the wrong way as I thought the original issue reported on the 2 1/2 Litre was related to too weak mixture.

But anyways, no problems with either of those needles on the 3 1/2 Litre. :slight_smile:


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All these needle diameter numbers are within a .090" jet. Smaller diameters as the needle moves up mean more open space in the jet and more fuel going up, along with more air through the throat as the piston moves up, if the throttle plate is open, and presumably a richer mixture. The Research Department would have tried a bunch of needles before picking one. All that for better immediate pickup.
BTW Peter where did you find the '38-40 needle letters?

I got the needle letters from a general information booklet that Derek Sharpe produced many years ago. Derek had a stall at Beaulieu each year. He may still do but I gave up going 9 years ago.