The front mud shields (left and right) prevent the ingress of water and dirt into the space behind the front side wings. It is evident that water and dirt will cause corrosion where in particular the bulkhead side structures are prone to rusting and repairing is a very labour (and thus cost!) intensive affair. For reference purpose, the front mud shields (or Diaphragm Assembly as Jaguar calls them) are identical for the OTS and the DHC but the FHC has different versions:
- OTS/DHC part numbers BD8401 and BD8402
- FHC part numbers BD10079 and BD10080
Where the mud shield stops at the bottom remains an opening between the lower part of the side wing and the extended door sill. Through this opening water and dirt can (over time) endanger the structural strength of the door hinges but also enter the cabin and more in particular the rear side of the trim panels left and right beneath the dashboard. This will certainly not contribute to the life of these plywood or Millboard panels, which is so often observed during a restoration. It is unclear why Jaguar left these openings exposed and opted to only partly cure the issue with the actual mud shield design, whereby so much attention was spent sealing the sides of the shield with a special rubber profile but nothing at the underside.
Mud shield extensions
It is possible to close the opening between side wing and door sill with a simple bracket made of sheet metal. The bracket rests at one side on the lower edge of the side wing and is fixed with (e.g. 3 bolts M6 or UNF ¼”) to the horizontal flange of the sill (extension). The forward end of the bracket is bended under an angle parallel to the mud shield and positioned under that shield. Material can be aluminium, zinc plated steel or even stainless steel of a suitable gauge. The example is made of 1.2 mm zinc plated steel that will be powder coated in black for extra protection.
Please note that( probably all) Jaguar XK bodies have some difference in their dimensions, so the drawing below should be used as a guide. Every given dimension should be checked against those of a particular XK body. The drawing is for the LH side of the car; the RH side is simply mirror image. The photo below gives an impression of the RH side bracket.
Once installed the bracket looks like this (see photo below). A small (draining) gap is left between the bracket and the beginning of the door bottom.
Crankshaft Torsional Vibration Damper Assemblies for XKs
Certain high speed in-line internal combustion engines are prone to torsional vibration of their crankshafts: the straight six and straight eight engines being particularly prone to this problem due to their long crankshaft length. A crankshaft vibration damper is required for which two basic concepts are applied: the frictional vibration damper (e.g. RR and Bentley) and the rubber bonded damper.
Mac Goldsmith (Max Goldschmidt) started his engineering company near Frankfurt (Germany) in 1925. He moved to England in 1937 and formed the Bundy Tubing company in Welwyn Garden City (north of London), manufacturing copper coated tubing. About a year later he established the Metalastik company in Leicester. Another famous Leicester rubber manufacturer, the John Bull Rubber Company, merged with Metalastik Precision Rubbers in 1955. In 1958 the group became part of the Dunlop Rubber Company Ltd. The Metalastik trademark is still used today by its new owner Trelleborg.
In the late thirties the Metalastik company introduced an improved and simpler design which is the rubber bonded metal disc type and this remained standard on many engines to this day. The Metalastik type is not just a damper, but rather a tuned and damped ‘vibration absorber’. The vibration absorber is a secondary inertial mass and spring stiffness, tuned to the first natural torsional frequency of the crankshaft assembly; this results in two new natural frequencies, one above and one below the tuned frequency, and a marked reduction in the amplitude of oscillation of the crankshaft at the original natural frequency. The inherent damping of the rubber ensures that the amplitude of oscillation of both the crankshaft and the absorber at the two new natural frequencies are within acceptable limits.
The 3442 cc Jaguar XK 6-cylinder engine of 1948 and most subsequent versions of the Jaguar XK engine used a proprietary Metalastik vibration damper to protect their crankshafts from potentially damaging torsional vibrations. To quote William Heynes in 1953, “The Metalastik damper consists of a steel plate to which is bonded, through a thick rubber disk, a malleable iron floating weight. Variations of the weight, rubber volume and mix, give these dampers a very wide field over which they can operate.”
The rubber bonding of the original Metalastik dampers is prone to disintegration through age and oil contamination. The rubber compound hardens and breaks up, which means that the damper is no longer absorbing crankshaft vibrations. Jaguar advises a deflection of the damper weight in relation to the crankshaft of no more than ½°; the torsional vibration damper should be renewed when the deflection is more than this figure.
Oct ’53 advertisement 1957 advertisement with cross section of vibration dampers (top LH)
1959 Metalastik advertisement: note picture of Jaguar damper and related text
Survey of XK crankshaft dampers
All XK 120/140/150 crankshaft dampers have been manufactured by Metalastik of Leicester, UK (since 1958 part of the Dunlop group). Most (all?) of the dampers have the following text stamped on the back (engine side) of the damper: METALASTIK PATENT T.V. DAMPER PART Nº 51/XXX whereby the last three numbers indicate the specific version. The abbreviation T.V. stands for “Torsional Vibration” damper.
Configuration of Metalastik dampers
The basic design of the Metalastik damper of the 51 series consists of a stamped dish of ⅛” steel (8” outer diameter, about 3½” inner diameter and a recess/depth of about ⅞”) to which a cast centre spigot for the damper-cone is riveted (12 rivets). The “floating weight” (or inertia disc) is bonded by thick rubber to the aforementioned steel dish. The material of the floating weight (9” outer diameter) varied over the years: cast iron, malleable cast iron and steel were used depending on the type of XK engine.
Two basic types used for XK’s
Metalastik manufactured three basic types for Jaguar (but also used by others like e.g. Austin Healey and Maserati). All crankshaft dampers with a cast iron or malleable cast iron weight (about ½” thick) were coded 51/177. The versions with a steel weight (⅜” thick) suitable for higher rev’s, were coded 51/211. Note that there was a third damper version coded 51/227, but these were only applied on 2.4 ltr engines and therefore never used on XK’s.
Over the years small changes have been made in particular related to the timing marks on the floating weight, but the Metalastik code number remained unaltered. Jaguar, however, changed the part number with every (minor) change, making it rather difficult to determine (more than 60 years later) what the corresponding Jaguar part number is for a particular Metalastik version.
1. Crankshaft dampers for Jaguar XK 120
1.1. Introduction engines 1948
First photos and drawings presented during the introduction of the XK engine in 1948 show an engine without a damper fitted to the crankshaft.
1.2. Jaguar part nº C2464 (Metalastik Part Nº 51/177)
From engine Nº W1001 (October 1949) to W8306 (May 1953) a Metalastik damper with a cast iron floating weight had been installed. The edge of the floating weight casting measures about 13.5 mm over 6.3 mm whereas the rest of the weight measures only 9.5 mm (see drawing with cross section of damper). Outer diameter of the floating weight is about 9” and the inner diameter 6¼”. There are no timing marks on the damper. This version was used until May ‘53.
1.3. Jaguar part nº C5809 (Metalastik Part Nº 51/211)
June 1951 saw the publication of the famous Service Bulletin 95 which gave a survey of the “Tuning Modifications on XK 120 cars for Competition Purposes”. Next to a lightened flywheel a “Special Crankshaft Damper Part No. C5809” was introduced which was “specially tested for operation at high rpm”.
In comparison to Part Nº C2464 the floating weight was made of steel instead of cast iron, apparently better coping with the continuous higher revs at which these dampers were run (maximum engine output now at 5800 rpm instead of 5400 rpm). The floating weight in steel measures only ⅜” (or 9.5 mm) instead of 1/2″ (or 13 mm) of the cast iron version, which relates to the difference in specific gravity. This crankshaft damper used a special rubber mix for the bonding of the steel weight. The Metalastik Part Nº 51/211 had the mark “COMP” stamped at the front (see photo).
Outer diameter of the steel floating weight measures about 9” and the inner diameter 6¼”. Total weight is about 3.3 kilos.
This damper was used on the following XK 120s:
1.3.1. Earlier and later engines modified for Competition purposes according SB95 replacing the C2464 damper
1.3.2. Engines in Special Equipment (SE) cars from June 1951
1.3.3. Engines Nº W8307 to W8380 (production month May 1953). Apparently the old damper C2464 was no longer available while the successor type C8020 still had to be manufactured. For these 73(?) standard engines damper C5809 was used.
1.4. Jaguar part nº C8020 (Metalastik Part Nº 51/177)
From Engine Nº W8381 (May 1953) a new Metalastik damper with malleable cast iron floating weight was used. Metalastik changed from a (grey) cast iron to a malleable cast iron version because of its more ductile characteristics.
The floating weight is about 13 mm thick at the edge. Outer diameter measures about 9” and the inner diameter 6¼”. This damper has no timing marks (or lines) at the front side.
2. Crankshaft dampers Jaguar XK140
2.1. Jaguar part nº C8241 (Metalastik Part Nº 51/177)
Engines with a standard cylinder head received this damper. This part succeeds C8020 meaning a Metalastik damper with malleable cast iron floating weight. By September 1954 this damper received 3 timing marks at 0 – 5 – 10° BTDC without any figures stamped above the marks.
2.2. Jaguar part nº C8129 (Metalastik Part Nº 51/211)
Used on engines with the C type cylinder head, this damper is similar to damper C5809 meaning the inertia disc was made of steel and used a special rubber mix for the bonding of the weight. As it was a 51/211 version it continued to show the “COMP” mark. It received 3 timing marks (lines) at 0 – 5 – 10° BTDC without any figures stamped above the lines.
Note that the stamping on the rear side shows the marking METALASTIKPATENT T.V.DAMPERPARTNº51/211 without any spacing between the words. This in contradiction to the Metalastik 51/177 version where there are spaces between the words and the part number is given in a second line.
For Metalastik the basic design was unaltered and they continued with their part number 51/211. Jaguar, however, changed the part number to C8129 because of the new timing marks. The outer diameter of the damper is 9” or about 230 mm. This damper has a ⅜” or 9.5 mm thick floating steel weight with an inner diameter of about 160 mm. The overall weight of the damper is about 3.3 kilos of which the floating weight takes about 1.5 kilos, meaning 46% of the total weight is in the inertia disc.
3. Crankshaft dampers Jaguar XK150
3.1. Jaguar part nº C8241 (Metalastik Part Nº 51/177)
All 3.4 litre engines from March 1957 onwards continued using the damper of the standard XK 140 engine. See under 2.1. From May 1960 onwards the TDC timing mark was continued on the edge of all dampers to facilitate timing by means of “modern” testing equipment.
3.2. Jaguar part nº C15274 (Metalastik Part Nº 51/211)
Late 1959 the 3.8 litre was introduced and received another updated version of the 51/211 crankshaft damper. Basic dimensions remained unchanged but the markings were new.
The damper version now had a full timing scale with marks at 0 – 5 – 10° BTDC and the figures stamped above the lines. Smaller markings every degree between 0 and 10°. The TDC timing mark was continued on the edge of the damper. Dimensions remained identical to C8129 and it still carried the mark COMP.
4. Later Crankshaft dampers Metalastik Part Nº 51/227
With the introduction of the 2.4 litre engines in 1955 the need arose to develop an optimised version for this (short stroke) engine. Note that Metalastik developed a third range of Crankshaft Dampers with Part Nº 51/277.
There were two 51/227 versions used by Jaguar:
- Jaguar Part No. C12037 mounted on 2.4 ltr. engines of the jaguar Mk 1 and Mk 2 (up to engine No. BJ6131) over the period 1955 up to 1963. These versions had one single timing mark (TDC) on the edge of the damper.
- Jaguar Part C24921 mounted on 2.4 ltr. engines of the Jaguar Mk 2 from engine No. BJ6132 onwards in the period 1964 till 1967. Here, however, the pulley and damper had been integrated.
Photo courtesy of Eric Kriss.
Note: all data in this overview are given in crank degrees and crank rpm.
The following information has been gathered from various sources (both Jaguar and Lucas), but the available information is at times unclear or confusing. Therefore the data should be regarded as “additional help” and not as the ”absolute truth”.
Jaguar used Lucas distributors for the engine of the XK 120, 140 and 150 (and of course for the Saloons of that era). For this overview to types of distributors are of interest:
- DVX(H)6A distributors for XK120 and XK140.
- DMBZ6A distributors for XK150.
Note the different lower aluminium housing of the DVX(H)6A (left) in comparison to the DMBZ6A distributor (right).
The difference between the distributors for the (early) XK 120 and 140 is mainly in the cap with horizontal spark plug cables for the XK 120 (up to 1953, recognisable in the letter H in DVXH6A) whereas later XK 120 and 140 distributors had vertical spark plug cables. A good example of that difference is the Lucas 40199 distributor which was used both in the XK 120 and 140: the XK 120 used the 40199A to D with type indication DVXH6A and the XK 140 had the 40199E with type indication DVX6A. The only real difference between the two being the distributor cap: 415708 for the XK 120 and 407043 for the XK 140. The XK 150 distributors of the DMBZ6A type are totally different from the DVX(H)6A types .
The surveys below also mention an E.C.M. curve which in fact describes the ignition advance from idle to maximum allowed r.p.m. as indicated by the manufacturer. There is a lot of discussion about the meaning of the term ECM as Lucas used in all of their ignition data.
In the Lucas “Overseas Technical Correspondence Course” Section 3 “Coil Ignition” Part 2 the following is explained:
Engine Curve: “In building up the many different advance curves required by the engine manufacturers, we operate from a curve taken from the engine test which shows the degrees of advance required at different engine speeds and loads.”
We may assume from this that Lucas was confronted with many different Engine Curve Models (ECM) and started to build up a “library of ECM’s” giving them specific numbers.
Ignition data for XK 120 engines
Ignition data for XK 140 engines
Ignition data for XK 150 engines
Reutter Reclining Seats as factory option for Jaguars.
The standard seat configuration of Jaguars from the Fifties results in a driving position which is far from ideal. In the early fifties. Jaguar understood that something had to be done, but no solution was available in-house. As far as we know, none of their British suppliers, nor competitors had a reclining solution at that moment.
There was one company that had been working on reclining seats after WW2 and had started production in early 1953. Reutter Karosserien of Stuttgart was a German company with a long history: established in 1874 by Wilhelm Reutter with his brother Albert joining the company in 1910. The company built special car bodies for many German brands like Adler, Benz, BMW (incl. Dixi) , Daimler-Benz, Horch, Maybach, NSU, Opel, but also for non-German manufacturers like Ansaldo, Austro-Daimler, Bugatti, Buick, Cadillac, Chrysler, Fiat, La Salle.
The Reutter Reclining kit (German: „Liegesitzbeschlag“) was introduced at the 1954 Geneva Automobile Salon.
The Reutter subsidiary “Recaro AG“ (derived from Reutter Carosserien) had been established on September 9th 1957 in Glarus (Switzerland). Reutter manufactured the bodies for the early Porsche 356. After the sale of the body works in Zuffenhausen to Porsche in 1963, the “Recaro AG“ company kept their headquarter of the “Recaro GmbH & Co.“ in the former Stuttgart body works. Next to complete seats also seat rails, reclining kits and head supports have been manufactured here. The RECARO Sports Seat was created in this period, which became a worldwide quality benchmark.
Other German manufacturers of reclining systems
Reutter wasn’t the only company manufacturing reclining systems in the early Fifties. The Hüls company (also named Hülsmetall) of Kamen (Ruhr area) made aftermarket systems for the Volkswagen Beetle and Bus that could be bought as an accessory; these systems were mostly manufactured in painted steel and didn’t give that “high-end” impression.
Another company was Keiper of Kaiserslautern (near Frankfurt) that had an almost identical solution as Reutter had, however with a large turning knob instead of the handle for adjusting the seat back. These chromed products were often used for the conversion of Mercedes seats (type 170V and W110). We have to mention here that keeper eventually took over the Reutter company in 1983, but more recently Keiper in turn was sold to Johnson Controls (USA) in 2010.
It is interesting to note that the Keiper system was available in the USA from 1954 onwards, long before Jaguar started with the supply of the Reutter option. Jack McAfee Motors of Sherman Oaks, California offered them for $35 for a complete set.
Reutter reclining mechanism
Reutter obtained a German patent (Nr. 881099) on the 29th of June 1953 for a „hinge mechanism for upholstered seats with adjustable back-rest“. Note that Reutter also obtained a British Patent probably to protect their (future?) interest in the UK.
Jaguar Reclining Seats by Reutter
After having contacted Reutter in Germany, Jaguar started the development of reclining seats based on the Reutter kits. The supply of Reuter reclining seats as a factory option (factory modified seats using the Reutter kits) started in 1958. In October that year for the first time on a Jaguar, separate reclining front seats became available for the Jaguar Mk VIII and Mk IX (having more or less the same seat). The factory option included both front seats to be executed with the Reutter reclining mechanism. Later it was also available for the Mark 2 and for the XK 150 as well. The Reutter option was in Jaguar’s program for about 3 year: from 1958 up to 1961. Note that Jaguar opted for an “older system” that was in production from 1955 onwards.
Mark VIII (1958-1959)
The Jaguar (UK) price list of October 1958 lists the “Reutter Reclining seats (per pair)” for the first time as a “Proprietary Optional Extra” only for the Jaguar Mk VIII and the (then new) Mark IX. Customers had to pay £52 extra for two recliner seats which doesn’t seem to be expensive if related to an amount of £1800 to £2150 for a complete Jaguar Mk VIII or IX in those days.
Mark IX (1958 – 1960)
The introduction of Reutter reclining seats actually coincided with the introduction of the new Jaguar Mark IX. Next to the above reference of October 1958 there is also the US Jaguar Price List from June 2, 1960 issued by the Jaguar Midwest Dist. Inc. of Indianapolis, mentioning the option “Reutter seats” with a Dealer price of $120 and a Retail price of $145.
XK 150 (1959 – 1961)
There are some references regarding Reutter seats in an XK 150 although no options-list seems to be available that explicitly mentions the Reutter reclining seat as a factory option. Jaguar XK 150 S 3.8 FHC with chassis number T8251328DN, produced around 18th February 1960, received apparently the Reutter conversion according the H&H auction specification of 2014. Another possible example is the XK 150 S 3.8 FHC with chassis number T825134DN manufactured end of February 1960 (with Reutter seats according Coys auction description of 1993). Photo’s of a third known example are shown below: a 1958 XK150 DHC RHD has 2 Reutter seats that apparently have been modified in a very early phase using new leather kits (with 7 pleats i.s.o. 9) .
I acquired a Jaguar XK 150 Reutter left hand seat (which later has been modified for application in an XK 140) but there is sincere doubt whether this particular Reutter seat was actually manufactured by Jaguar for the XK 150, as this conversion was far from professional (see photos).
“Reutter” for the Jaguar Mark 2 ?
We noticed that some Jaguar Mark 2 cars for sale refer to have “Reutter seats”. Even Nigel Thorley in his book Original Jaguar MKI/ MKII mentions on page 64 “Reutter Reclining front seats” available as Optional Extra. It is very unlikely, however, that Reutter kits have ever been used for the conversion of early Mark 2 seats .
We had to conclude that all examples of Mark 2 cars claiming to have “Reutter seats”, did not have a reclining system manufactured by Reutter. So it looks like “Reutter seat” had become a generic name for a Jaguar reclining seat in this era. Jaguar issued a special brochure on reclining seats for the Mark 2 in which it mentioned “Special Jaguar reclining seats”, whereas for the Mark IX cars Jaguar spoke openly about “Reutter reclining seats”. This later Jaguar reclining system was manufactured from March 1963 onwards and is also mentioned in the Jaguar Mark 2 Spare Parts Catalogue. This catalogue also mentions a “Kit of Parts” (Jaguar BD.24397 (LH) and BD.24432 (RH)) for converting a rigid Mark 2 seat into a reclining version. These Jaguar systems can be easily recognized by having a separate chrome handle positioned below the hinge plate (instead of above the hinge plate as per Reutter).
Reutter influence on E-type (XKE) Series 1 (1964 – 1967)
Although none of the E-type (XKE) versions ever had a Reutter system installed, we still mention the Series 1 from 1964 (coinciding with the introduction of the 4.2 litre engine) up to 1967, because the design of this reclining system was clearly inspired by the earlier Reutter version: the shape of the aluminium casting was derived from the Reutter design.
The Series 2 models had a completely redesigned reclining mechanism, no longer supplied by Reutter.
Other period cars with Reutter reclining seats
Most obvious user of Reutter reclining mechanisms was of course Porsche: their 356 models had them from 1953 onwards (even before the official 1954 introduction in Geneva). Other car manufacturers in the 50’s that used Reutter reclining mechanisms were: Alvis TD21, Aston Martin DB4, Bentley S1, Bristol 406, Volkswagen Beetle and Bus (T2, T5), Volvo (B16 and pre 1965 B18), Mercedes, Borgward, Facel Vega, and probably many others.
Reutter seats on Aston-Martin Bentley S1 with Reutter seats Borgward Isabella with Reutter option Volkswagen Beetle with Reutter option
Overview of recliner mechanisms.
There are two basic types of Reutter reclining mechanisms that look almost identical. The first version had a rather long arm with three mounting bolts connected to the back rests. This version was already in production by 1955 and modified a number of times, differences mostly related to the shape of the aluminium cover over the large spring. The above examples, showing a spring cover attached with 2 screws to the upper arm, often have a date code from 1955 if applied in German cars. The Jaguar versions, however, have the “British Patent” stamped but lack a date code.
Although the Reutter system for the Porsche 356 C (1963-1965) looks identical to the aforementioned version (3 mounting holes and black adjustment knob), the above shown later version cannot be used for the Jaguar seats as the installation and synchronization is completely different.
From about 1957 onwards we also see versions whereby these arms had been replaced by a shorter version with only two bolt holes. Note that both versions have already been described in the original patent application of 1953. Not used on Jaguar seats!
Jaguar applied the first Reutter generation type from 1958 onwards and kept this model over the entire period of Reutter reclining seats up to 1961. All of these hinges have steel tubes that connect the LH and RH hinges on each seat.
The reclining mechanism
Reutter used chromed aluminium castings rotating around a spring-loaded hinge. These assemblies were placed at both sides of the seat (LH and RH castings). The LH and RH mechanisms were connected by a cross-over tube “synchronising” the seatback movement. A short lever allowed the position of the backrest to be changed relative to the base using a gearwheel mechanism coupled to the cross-over tube. The casting mounted to the backrest was longer than the one connected to the seat base. The castings were fixed with 3 bolts to the seat back and with only 1 (swivelling) bolt to the seat base: this allowed the seatbacks to be hinged forward in order to get to the rear seats.
Jaguar XK 140 FHC recliner seat conversion
As the introduction of Reutter reclining seats as a factory option started only in 1958, it seemed unlikely that this option was ever used for the XK 140 series. However, there is apparently (at least) one example of an XK 140 with a reclining seat installed by the factory: Jaguar build records show that the (RHD) XK 140 FHC with chassis number 804574 (registration number WNK 843) was manufactured on 20th December 1955. The first owner is registered as Major Robert Cunningham-Reid. Mr Cunningham-Reid has confirmed that the car was modified by the factory with a Reuter reclining seat on the driver’s side.
I obtained an XK 150 seat with Reutter reclining mechanism and converted the original Jaguar XK 140 (FHC) driver seat to a reclining version. It requires a complete dismantling of the seat and some constructional modifications, however none of them are too complicated.
The distance between the LH and RH reclining assemblies is determined by the frame width of the seat base (see photo). As the base frame of the 150 seat is 35 mm wider than the one of the XK 140 (about 423 mm), the existing Reutter system had to be modified in three ways: (1) the cross-over tube had to be shortened by 35 mm to fit and (2) spacers had to be used for fitting the RH recliner assembly to the metal inner support construction of the seat back and finally (3) a piece of plywood is placed on the outside of the LH side to compensate for the spacers on the other side (see photo).
Note that the ends of the cross-over tubes are square on the insides (to fit a gearwheel) and therefore the tube has to be shortened in the middle: use a solid rod to reinforce the middle section before welding the tube.
Another modification relates to the stops for the seatback: the original “stop section” on the rear of the base frame has to be cut off and replaced by a new section (see photo).
On the XK 140 seatback frame the original hinges have to be removed as their presence is no longer required (see photo).
Bonnet Louvres for XK 140
One of the ways to keep the coolant temperature under control is to increase the amount of air through the radiator. Next to installing an electric cooling fan, bonnet louvres may help (of course under the condition that the car is moving). The latter solution also doesn’t consume any power from the engine. This is the reason why in particular race cars (including Jaguars) had louvres installed in bonnet and/or wings.
Jaguar used this principle for their XK’s and installed louvres in various versions that took part in active racing. In particular during the early years, C-types and some XK 120’s received this option, but there are also at least two examples of the same operation for the XK 140.
It is rather difficult to obtain exact data on the position, number and size of the louvres in the bonnet of the XK120 and the C-types. Furthermore, we note that the dimension’s differed per type and per year because they were made by hand and the development of the cars continued of course. What becomes clear, however, is that there are always two rows of louvres symmetrically located at both sides of the middle of the bonnet.
(All dimensions given here serve to help getting a better insight, but claim in no way to be exact).
Louvres for XK 120’s
Most prominent example is Clarck Gable’s second XK 120: a 1952 steel-bodied OTS with chassis number 672282. After his complaints regarding the lack of ventilation in the engine compartment Jaguar punched two rows of slots in the bonnet (see below).
Jaguar XK 120 OTS Works Competition car with registration MDU 524, had a different bonnet louvre pattern. This originally May or June 1952 built RHD OTS with chassis number 660986 is well-known after it had been extensively modified in 1953 to become the streamlined car that set a speed record of 173.159mph on the Jabbeke motorway in Belgium. Before and after that event it participated in a more standard execution in many races in the UK driven by Albert Powell and Brian Redman.
Whereas Clarke Gable’s car had triangular shaped louvres almost over the entire bonnet length, the MDU 524 louvres have an almost square lay-out, much more in line with the later XK 140 patterns (as we will see below).
Louvres for XK140’s
Most prominent example of an XK 140 FHC with bonnet louvres is the 1956 Le Mans car driven by Peter Bolton and Bob Walshaw: registration number PWT 846 and chassis number S 804231 DN. This was a SE version in standard form with apart from the optional 2” H8 carburettors and an additional fuel tank, also got extra air intakes at the front and louvres in the bonnet.
Clausager in his book “XK 140/150 in detail” shows a detailed photo of the louvres which reveals that they have not been made straight in the aluminium bonnet material itself but made in a separate plate and mounted from behind in an opening cut in the bonnet. The louvres are pushed through from the inside and the air opening is in the direction of the windscreen. We count (two times) 16 louvres with an estimated width of 185 to 190 mm (7¼ to 7½”) over a length of about 445 mm (roughly 17½”). This implies that the individual louvres are about 28 mm (1.1”) wide with an opening of about 12 mm (½”). The louvres are placed very close to each other without any space between them (which somewhat reduces the mechanical strength of this section and louvres can be easily bend).
Regarding the exact location of the louvres on the bonnet, the position on the Le Mans car is towards the end of the bonnet close to the windscreen. This was only possible by removing the aluminium reinforcement construction on the inside of the bonnet and welding it back after the louvres have been placed (what may restrict the air flow).
The second example of an XK 140 with bonnet louvres is an early “experimental” OTS (most likely chassis number S 8000033 DN). This car had two additional air intakes at both sides of the grill above the bumper and bonnet louvres, very much in line with the Le Mans car (which was a much later car). It is impossible to reproduce the exact measurements of these louvres, but they seem to be close to the ones of the Le Mans version.
Louvres in C types
Looking at photos of C types we see for the 1953 versions a different pattern for the louvres: two groups of 22 louvres over a total length of about 610 mm (24”) and a width of 210 mm (8¼”), meaning 28 mm per louvre which is identical to the spacing used for the XK 140 (same tooling?).
Making bonnet louvres in an XK 140
When making louvres in an XK 140 bonnet, there are two alternative ways to go:
1. Making two separate plates with louvres and fix those in an opening cut in the bonnet.
2. Making the louvres straight in the bonnet.
When opting for the second method, limitations are created by the reinforcement construction at the inside of the bonnet: the louvres cannot be placed as close to the windscreen as was the case for the Le Mans and Experimental car. And the total available length for the louvres between two reinforcement brackets, allows only for about 10 openings (spaced at a distance, because a certain strength of the bonnet will be appreciated!). The louvres are cut and formed with a special tool and machine (see photos) and the result is very satisfying.
Lucas SFT576 Fog lamps on Jaguars
From about 1954 Jaguar introduced 5¾” Lucas SFT576 fog lamps on most of their models, either standard or as a factory option. Before ‘54 they used the larger 7” Lucas SFT700 as an option only. The Jaguar XK120 had the Lucas type SFT 700S (Lucas assembly no. 053135/A; Jaguar code: C2988) as an optional extra including mounting brackets and a switch. This version is not further discussed in this article.
There are two different versions of the SFT5776: first generation manufactured from 1953/54 till probably mid 1963 and a second generation from mid 1963 onwards.
The Lucas SFT576 showed some modifications over the years. Early SFT576’s have a smooth flat upper top clamp where asthe later versions have a ribbed surface.
A second difference relates to the (Single Contact) bulb holder. The early version have a round black “Bakelite” bulb holder (Lucas 554667) and later versions have a more simple oval shaped bulb holder made from phenolic (Lucas 54520352). The exact change-over date is still under investigation.
All these fog lamps use a 12 V single contact 48W bulb (Lucas 323) with transverse filament placed in a clear reflector unit (Lucas 554813). Note that there are also “double contact” SFT576 versions, as used by Rolls Royce that require a specific bulb (Lucas 409). The corresponding bulbholder (Lucas 554822) is different and should not be used on any Jaguar.
Lucas production of SFT576
Lucas started production of the SFT576 around 1953 with the 55128B versions (55133B for France with yellow reflector unit Lucas 554820). In the years thereafter the 55128 version received suffix D and towards the end of the decade suffix E.
This version (55128E) had a new bulbholder made from phenolic sheet material (Lucas 54520352). However, Jaguar no longer mentions this version for their later models (XK150, Mk VIII and Mk IX) but refers instead to Lucas 55174D or even 55174E. Apparently the XK150 models had the 55174D version from its introduction in 1957.
To make life even more complicated, we have to mention here that early 55174 versions had the smooth whereas later versions had the modified upper clamp with “ribbed” top surface (see photo above).
Mounting SFT576 on XK’s
The installation of SFT576 lamps on the XK140 and 150 is rather unique, as jaguar used a “Distance Collar” to obtain a higher position for the fog lamps, still using the Front valance behind the front bumper as a base.
The use of this Distance Collar (Jaguar code BD.9240 for XK140 and/or BD.14162 for XK150) caused some problems as the standard fixing bolt (Lucas 503890) has only a limited length (55 mm) and is too short to use it with a standard nut (Lucas 180377) as used for most other cars that had this fog lamp type. So how did Jaguar solve this?
Initially Lucas had two types of Fixing bolts. The standard version (Lucas 503890) was a 55 mm (2.2”) bolt used in combination with the standard nut 180377; unfortunately early Fifties Lucas catalogues did not mention the standard fixation bolt so this number (once source only) still has to be confirmed. A second (longer) version was made for the use of the SFT576 on Bentley and Rolls Royce cars: this fixing bolt (Lucas part number 503014) is 105 mm (4⅛ “) long. The 1960 Lucas catalogue uses this longer version for all SFT576 versions, apparently under the motto: “long enough for all applications” (or cut to size). The thread used by Lucas (and Jaguar) is BSC ⅝- 26 tpi whihc is British Standard Bicyle thread.
Standard bolt Lucas 503890 (RH) and long bolt Lucas 503014 (LH) for Rolls Royce & Bentley (photo right)
The solution Jaguar introduced comprised a special extra long nut Jaguar BD9241 for the XK140 and/or BD14163 for the XK 150. Please note that some suppliers use part number Jaguar 5220 for this nut, but this is actually wrong as this refers to the Lucas “short” nut 180377. The extra long nut partly fits within the Distance Collar and is long enough to reach the thread of the shorter standard fixing bolt. The difference between the two versions (BD9241 and BD14163) is unclear but they might have a different length as the replacement version that is supplied at the moment is shorter than the earlier ones.
Jaguar’s solution with “long nut” and “collar” . The longer nut (from date code 1961) might be BD14163.
Next to the Nut and Collar a shakeproof washer (Jaguar C.733) is used and a special Packing Plate Jaguar BD104160: the XK 140 SPC specifies one per lamp, but later versions have the description “as required“. The photo above shows a 1961 item with two Packing Plates.
Finally: it is also possible to use a standard nut (180377) instead of the special Jaguar long nut, by using a 105 mm long fixing bolt (Lucas 503114) and cut to size.
Fog lamps light units
The original units had Lucas number 554813 (clear front glass) and for France 554820 with an Amber front glass. These versions had the (factory) code M5 and the text “MADE IN ENGLAND” at the bottom of the front glass. Modern replacement units don’t have these markings, but are otherwise identical.
Fog lamps as an Optional Extra for XK 140
Fog lamps could be ordered as an optional extra for “non-SE” cars.
The official parts list indicates that in that case the existing 3-position Road Lights switch (Lucas PRS7 type 31426/A) has to be replaced by the 4-position switch (Lucas 31524/A). A Red/Yellow wire is then installed from the new switch (position 11) to the Fog lamps.
Apparently early cars (as was the case for the XK 120 versions) could have a separate Fog Lamp switch mounted on the Instrument Panel. The wiring diagram (Nº W 26880, November 1954) proposes an independent Fog Lamps switch of the PS7 type (pull/push: on/off). A new Red wire is running from connection 7 of the 3-position Road Lights switch to the separate Fog Lamps switch. Another Red/Yellow wire is then installed from the Fog Lamps switch to the Fog Lamps.
The change-over from an independent switch to replacing the 3-position into a 4-position Road Lights switch has to do with the question whether in a particular country (state) it is by law required to switch off the Head Lamps when the Fog Lamps are turned on.
The Fog Lamps PS7 switch used for the XK 140 is Lucas 31389A (Jaguar C5631). This Lucas part number has been later replaced by 31434. This is a panel light switch without a knob. The correct (push-on) knob used for this application is black with a white “F”. The corresponding Lucas part number is 312866.
The exact position of this independent Fog Lamps switch is unclear. We do know that cars with 2” SU carburettors have an additional Choke cable + knob installed in the wooden Instrument Panel to the right side of the drawer. This might well be the place to mount the Fog Lamps switch. However, this switch doesn’t seem to have a long thread required for mounting in a (thick) wooden dashboard (as did the earlier XK 120 switch) , but it may be possible to solve this by creating a recess at the back of the panel allowing to position the switch more to the front.
Later a complete Lucas kit became available under part number 053272 (which also succeeded the former independent item Lucas 55128/x) containing a switch Lucas 31201/D, knob Lucas 314403 and even a mounting bracket 056117. This should apparently be mounted beneath the (wooden) dashboard.
The Jaguar XK 120 used a similar set-up . Early XK 120’s having factory installed Fog Lamps may have been executed with a chromed knurled knob screwed to the switch. Later versions may have Fog Lamps installed as an “Optional Extra” with a separate switch having Lucas part number 031216 (Jaguar C2744). The Lucas Master Parts Catalogue indicates that assembly 031216 consisted of a PS7-1 type switch 31228A (an Interior Light switch with long thread for a wooden panel, similar to switch 31201 except for length of thread) and a black Bakelit knob 314437 without “F”. This switch was positioned at the end (driver side) of the Instrument panel (according Urs Schmid).