I recently acquired a 1954 XK120 SE OTS that is a matching numbers factory original 9:1 compression car (Engine number ends with -9S). I have contacted the Jaguar archives in New Jersey and spoke to Fred Hammond about it. Fred actually went into the hand written info from Jaguar and no luck with ownership info. I also have a heritage certificate, but again the original owner was not recorded by Max Hoffman when the car was sold new which is common. I have read and discussed with Fred at Jaguar that there were only 22 9:1 cars originally built and only 13 of those are left hand drive. My question is why were so few ordered as 9:1 compression? Were they built specifically for racing purposes? Would they have all been ordered by someone of importance for racing? or was it just an option that nobody ordered for no reason? It makes no sense and there isn’t much info about these cars. Also besides being 9:1 compression did these cars have other things done to them? Such as a lightweight flywheel, sand cast carbs, bigger valves, cams etc… Any information pertaining to these few special cars would be really great to hear so any help in shedding light on this subject would be great. Thanks so much!
I also would like to add that my car has a real factory installed C-Type head (part number C7707) which adds even more to the mystery
Alex, would you post an image of your Heritage Certificate?
Service Bulletin #95 dated June 1951, re-issued June 1952, says the 9:1 pistons were available then as special order, and there is a whole page of other racing parts that a customer could have bought.
The improved cylinder head with revised porting and enlarged valve throats became available with Service Bulletin 95A dated April 1953, as did the 2" carbs and appropriate manifold.
We’ve discussed this SB before, and believe that the new head was initially not painted and without the letter C in the valley.
We would be interested to see pictures of yours, including the stamped number usually located on a rectangular plinth at the rear of the valley.
Here is an example.
All part of the gradual accumulation of accurate information about these cars.
Rob, thanks for your info. Attached are photos of the engine numbers as well as the head casting number and stamped number at the back of the head in the valley. I also attached a photo of the firewall tag. Interestingly my car also has an odd tachometer as well, it has a green colored redline (photo attached). As for the heritage certificate I can get a picture of that tomorrow but the car is listed on the XK data website with more pictures. It was originally cream color with blue interior and a blue convertible top, now it is red. with tan. The original color combination is very different, but very nice at the same time. This is a very interesting car. I just don’t understand why there were so few ordered this way. I wonder if this was considerably more expensive and purchased for racing purposes?!
By the way, no “C” cast in the valley of the head either
This head looks like it started life as a C 7700 C2. Cast by West Yorkshire. Very early “type C” head, without the “C” cast in the valley. The last 7 looks like it was stamped over the ground off 0. Most “type C” heads are C 7707 C3. This C 7700 head was used as the starting point for the 1954 D-type Le Mans head. The early D-type had the 7700 number ground off and 7896 was stamped in it’s place. I know of a head with this configuration, tail stamping number AK 528. Close to your AP 407.
This is a very cool find!
The green colored redline is very unique, but that’s not the only difference. The standard XK120 tachometer has a small peg to rest the needle at 200 rpm when the engine is off. On your tachometer, the small peg is situated so the needle rests at 0 rpm when the engine is off.
alex hate to be a party pooper old news! I saw this car at your premises in 2013 just on 6 years ago and Expressed my great thrill to Mannie I think it was (but certainly one of the Dragone family) to have only seen the second -9S XK120 in 45 years of Jaguar from memory only 32 such cars exist. I have also seen a straight -9 car one of one or two.
The car was to be auctioned a few weeks later and noted that it should have an increased value or at least interest.
But good to see you are following up on it! albeit 6 years later!
I assume it was sold at auction and has been traded back in?
It is a very late car and was in very good original condition ie not a total restoration to get it back to good condition so I see it was either a top spec car ordered by someone who wanted all the goodies though no H8’s or it was ordered as a race car still no H8’s but not destroyed whilst racing.
Love to get old owners details rego papers as it is a unique car.
I have had a -9S XK140 FHC still have the motor
I had also noted the tacho going colour on the red section and had no idea as to what the story was unless some sent face out for resto and some thought it looked better in green
Hi Terry, Yes we had this car in one of our auctions years ago as you saw and it was sold to a gentleman locally here in CT. I have recently purchased the car back. This car at that time of the auction was owned by another gentleman that owned it for many years. He actually vintage raced it a bit years ago and had Weber’s on it at one point. He then restored it for show later as you saw it and he put SUs back in but couldn’t find H8s at that time. This car had H8s on it originally according to that owner and I believe it being an SE with 9:1 compression with a C-Type head. I asked him about it’s previous ownership and he could not remember where he purchased the car from because it was so long ago. I don’t believe the tach was touched, it looks original to me. This is such a great car and I’ve never seen one like this before. There’s no way someone would have ordered a car like this for street use, but I would love to learn more about it and why so few were ordered like this. Do you think it is possible it could have been ordered for MoMo or a race driver?! I wonder why more people didn’t order 9:1 cars and I also wonder how much this car cost when new?
Possible due to the lower grades of fuel available at the time?
Alex,
Most interesting XK120 being an exceptionally rare example of an XK120 factory delivered from new with a C-type head, in this case the expected C7700 C2 casting (second variant). This is in fact rarer than being one of the reconciled 33 XK120 Engines fitted with 9:1cr pistons, and thus Engine Numbers with a -9S suffix. I have been recently in detail discussion with another owner of a factory delivered XK120 with C7700 C2 casting C-type head, but an -8S engine, and another owner of a factory delivered -9S suffix engine, but with the normal A-type Special Equipment head.
With all your photos, there remains one important piece of information missing. On the underside surface of the Head - on the inlet side, front unmachined field there will be a cast WYF logo, but alongside is the Casting Sequence Number of form RHxxx. Can you take a photo, or if not, at least advise the actual CSN.
Its impossible to confirm/verify what carburetters were originally fitted by the factory - H6 or H8 as -9S engines and/or C-type heads were factory fitted with either given you no longer have the originals that could have been accurately dated, and thus confirmed as being most probably the originals for your July 1954 build engine, or dismissed as definitely not original. (This information may still exist in factory archives, but so far has yet to be discovered, so may well have been destroyed in factory fire in 1957). The H8 carburetters factory fitted to C-types and a small handful at most of period 1952-54 XK120s, are distinctly different from the (relatively) common H8s as fitted to a handful of XK140s originally, and readily available aftermarket spare part H8s in late 1954 to 1957. Indeed I recently acquired a pair of these 1952/4 C-type/XK120 H8s, that are nearing completion of a 100% authentic cosmetic/functional restoration.
But great to confirm another XK120 with a factory fitted from new C7700 C2 casting C-type Head (none of these have the large cast in ‘C’ as with XK140 era C7707 C3 casting C-type heads, and indeed were NOT painted red originally)
Terry,
This is not old news. You have missed the key point that this head is C-type spec fitted to a new XK120 ex Jaguar factory. The XK120 -9 or S engine number suffixes indicate 9:1 compression ratio or Special Equipment. Neither signify a C-type spec head and with factory records not providing this detail the only way to know is to examine and understand the numbers cast on the underside and stamped at the rear of the valley.
This head, F3820-9S, is the fifth confirmed C head I now have recorded as fitted by the factory to a newly built XK120. The first came to light two years ago. Confirmed, in that the stamped engine number has an original F prefix and the cast part number is C7700 C2 then over stamped C7707. These five sightings of engine and chassis numbers all tie in with the data in Jaguar’s car record book.
The 9:1 cr is therefore a pointer to an engine being C-type spec but not definitive. As you know, the two XK120 RHD FHCs dispatched with 9:1 cr engines have lost their original cylinder heads, so we will never know if either car was C-type spec ex factory. S669125 goes under the auction hammer at the Goodwood Revival next month; note also it has the later XK140 H8 carburetters.
I concur with 53ctype’s findings that the C7700 C2 head was also machined to D type spec. I have two recorded instances of this, with the original cast part number over stamped C7896. The 1954 Le Mans D Type engine factory build sheets list the head as part C7896. I also have three further recordings of C7700 C2 heads machined to C type spec, but none are stamped with an engine number. So, in total, ten confirmed original C7700 C2 competition heads machined by Jaguar in the first half of 1954 i.e. before XK120 production ended.
Of course, these WYF C7707 C-type heads post date the William Mills heads fitted to C Type racing cars. Interestingly, I have two recorded W prefix XK120 heads which have a Q prefix casting sequence number. They are not E prefix engine numbers (i.e XKC) which debunks the theory that Q prefix = C Type racing head.
Regards
Simon