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This FiBoy's Mk1 website is devoted to a restoration or actually a rebuild of a Mark 1 Jaguar 2.4 litre saloon. Updated 16-helmi-2015

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"What might have been"

Jaguar Mark 1

The Jaguar 2.4's potent performance breed from the famous DOHC Jaguar XK engine breathing through two Solex downdraught carburetors. It had a chrome-iron cylinder block, high-tensile aluminum alloy head with hemispherical combustion chambers and aluminum alloy pistons. The twin overhead camshafts were driven by a two-stage roller chain. Power delivery was via a Borg & Beck hydraulic clutch to a four-speed gearbox with optional overdrive. From a standstill the Two point four could touch 96 km/h in 14 seconds and  reach 160 km/h with 112 bhp@5750 rpm. Equipped with the SU carbed  bigger engine the Jaguar 3.4 litre was a super car of its own time, 0-60 MPH was reached within 9,1 seconds.
A total of 19,992 cars were produced before it was replaced by the Mark 2. The car's length was grossly exaggerated in these early brochures!


Jaguar Mark 1Saloon arrival My car was lurking from the barn. Twenty years of dust had been collected onto the windscreen. It looked much better than the true condition was. 

This Mark I was originally named Jaguar 2.4 L Saloon. Because it is a -57 model it has already the wider grille than before. It was a Two Point Four Special Equipment Model identified by it's handsome Jaguar radiator mascot. The Jaguar Two-point-four was the first incarnation of Jaguar's "Small" saloon aimed at the developing executive market.


Jaguar Mk 1 front suspension The former owner, who rescued the hippie colored car from Helsinki, is standing to the left. Smile on Risto Jalava's face is understandable, he gets rid of all that accumulated dust as well as a heap of other problems. My face tells that I was anticipating hard times! 

On the other hand I felt relieved as I finally got an own compact Jaguar. Earlier my typical pose was like this - admiring other's wrecks - and dreaming!


Jaguar Mk 1 body The 2.4/3.4 litre saloon  has a neat 50's style roofline and quite heavy door window surrounds and pillars. I was dreaming of changing the sideline to follow the wonderful contours of Jaguar Mark I Coupe that was an early study made at Jaguar factory - it is a pity that it never commenced. Widening of the front doors, changing the door pillars etc was however such an immense job that I decided to leave that to followers. Still, this design study shows some immortal beauty values like big wheels, low roof line and sleek differentiated lines.

The body was rusty and marks of early, not finished repairs were visible. 


Jaguar xj40 rear suspension in Mk 1 Restoration of a good original car is a state of mind for many who have not experienced the joy of building  a car to their own choice! I wanted classic Jaguar looks combined with modern drivability given by EFI, ZF-box, good brakes and IRS. Nobody had done it before so it was challenging enough!

To the left an original XJ40 spring mount is waiting for installation. In this picture it is in place. And here the modified rear end ready.

There are not many sites with good pics in the web dealing with Mk 1 renovations, but here is one.


Jaguar Mk 1 chassis

The 2.4/3.4 L sedan  was the first unit-construction saloon of all Jaguars and therefore it was conservatively overdesigned  and was actually quite strong. However, I felt that a modern 3.6L AJ6 engine + the XJ40 transmission line generates so much fresh HP to rear wheels that considerable body strengthening was needed. Note the upper sill, actually a heavy gauge (107*2mm) steel pipe forming the inner sill. This is the same pipe as was used for reinforcing my Coupe. Outer sill will be a std. replacement item.


Jaguar Mk 1 transmission tunnel The additional outer flat floor (not original) of this Mark1 conceals a specialty; radiant under floor heating! It, however proved to be inefficient due to thick noise insulation mats

Wider tunnel was needed due to engine inclination. The last pair of xj40 silencers were later eliminated, they were superfluous.


Modified Jaguar xj40 IRS The XJ-40 IRS had to be shortened in width, 120 mm in total. Otherwise almost standard, the mounting rubbers now facing to the front instead of sideways . 

The petrol tank had to be cut down by 5 liters to make enough space for the IRS, still featuring the drive leveling hydraulic system. The differential has Power Lock and the ratio is 2.88:1 giving relaxed cruising. Because the petrol consumption went down, the smaller tank doesn't constitute a problem.  


Jaguar xj40 upright in Mk I The first concept was to try xj40 stub axle carriers together with original wishbones. This was no good, a spacer increasing the carrier height  was badly needed to fix the bump steering. The front springs were of heavy duty type (from a 420) but proved to be too soft. The best option was to use shortened Mk10 springs;  roughly 2,5 full turns on right side and ~1,5 turns on driver's side.

Steering conversions using Series III racks are popular but I opted for the XJ40 rack & pinion, because it is smaller in size. The number of turns lock to lock is only 2.7. The only complication are the mounts, using the SIII rack is much easier in this sense.


Jaguar xj12 upright The steering geometry was not ideal in the first version. Later the hub carriers from XJ12 were adopted, and simply by turning the upper fulcrum shafts perfect geometry was achieved.  Right positioning of the rack is very essential - but when done properly it is a worthy option. Now the front suspension works fine. Upgrading the front brakes with SIII V12 calipers was easy in this case and they match well with the XJ40 rear brakes.

One thing is still awaiting and that is a custom made 3/7" sway bar. Already the standard 2.4l was in respect softly sprung and the available stiffer one did not fix the problem in my case due to  the increased car weight. 


Jaguar Mk 1 floor  

Repaired floor and modified bulkhead. My car is originally imported to Finland and has chassis no. S-942572. Original color was grey as most Jaguars had that time, including my Mk7.  The donor XJ40 was a US sold SAJHV1542JC510194

Because the car was to use XJ40 electric front seats no supports for the chairs were needed as in the case of original arrangement. Also the new cross-member is therefore slightly lower than the original, just to allow the new seats, the electric sunroof and a high hat a'la  Humphrey Bogart to be enjoyed simultaneously. Yes, there is plenty of headroom! 


Jaguar Mk 1 rear wing The rear wheel arches were opened and widened to adapt same track as in the front. The Jaguar XJ40 IRS wishbones and drive shafts were accordingly shortened by 60 mm. The visible  hole is an air vent. The antitheft alarm is also installed there, it has an opening to this air vent pipe.


Jaguar Mk 1 air intake The breathing is assisted via a ducting going to front small grille like in the original Jaguar Mk1 set-up. The left inner wing  was opened a bit to adapt the inclined engine's systems. Air filter is underneath the left wing. 


Jaguar Mk1 front wing The right wing of the engine bay had to be modified to accept a service access, secured with a number of nuts. The A/C compressor will be serviced from here. 

Original hole for the brake servo was much smaller.  


Jaguar Mk1 engine bay with AJ6 motor The AJ 6 engine fits nicely but tightly into the available room. Actually only it's length causes some concerns. Without all the ancillaries there is plenty of room. Adding components leads to this

Original, replaced pedals seen here. The wiper motor is in original location - but the identification plate had to be placed onto the A/C box for better visibility. The narrow transverse "battery tray"  in the engine bay is formed of a rectangular steel profile. When that was opened underneath the A/C (opening visible only on right hand in this pic) a good channel for air flow was formed distributing hot/cold air from the A/C to the driver's side.


Jaguar AJ6 gearbox & transmission mount The ZF 4HP22 automatic gearbox from - 88 XJ40 is wider than the original and hence the transmission tunnel has to be widened. The original XJ40 rear mount fits easily. As the gearbox is not electrically controlled the installation to an older Jaguar is easy. Being a 4-stage automat it is really nice to have - a worthy option to any of the Marks! The fourth gear is a .73 overdrive, with lock up converter this gives high MPG. Excellent transmission! 



Jaguar Mk1 sunroof Mark 1 was not originally  available with metal sunroof. This (manual) option came first to the Mark 2,  which had specially reinforced body in that case! Jaguar XJ 40 has a sunroof with relatively small electric motor and reliable function as I had learnt from my Sovereign. I decided to give that a try. The curved roof caused some problems to the fitment. However, these problems were solved by cutting the frames into halves, which were then easier to bend to the right form. After re-welding the assembly fits.


Jaguar Mk1 sofa The MKI rear seat is well formed. It only needed new soft Connolly leather.

Note the use of the cabin below the seat. As new sheet metal was welded underneath the bench bottom during preparation of the Jaguar XJ40 IRS mounts, closed cabinets were formed, which were now utilized as loudspeaker boxes. 


Jaguar Mk 1 sandblasting When all major mechanical changes were finalized and the fitment was checked then the MarkI was stripped and sent to sand blasting. 


Jaguar Mk 1 rear Zinc epoxy primer was used all round and then the tar modified coating to underside. Conventional red epoxy to the body. The protective paint system for the MKI was designed by . The 12" subwoofer needed a matching hole. The hand rest on the other side renders the opening for the loudspeaker, but being used only for basses it does not have to be folded down.


Jaguar Mk 1 sandblasted  and primed After sandblasting and priming the MK I came back to my garage for sound insulation. Range Rover is the car to choose for towing in these winter conditions.


Jaguar Mk 1 sound proofing Quietness was one of the targets and different kind of noise deadening materials were used. The black mat is bitumen based heavy stuff, which is easy  to handle with a hot air blower.


Noise killer in Jaguar Mark 1 The MKI body was painted inside with Noise Killer, a special noise suppressing paint widely used by car Hi-Fi enthusiasts. In this case maybe superfluous treatment but interesting stuff!


Jaguar Mk 1 multilayer sound deadening The MK I machine room got a layer of modern multilayer insulator consisting of foam, bitumen layer, foam and an aluminum top layer. As a result the car is very quiet now, except wind noise that still has to be sorted out.

The body got it's final paint after all insulation was installed.


Jaguar Mark 1 painted engine bay The body was painted inside onto the insulation to give neater looks. Comparison to the original Mk I seen here.

The left side is modified to offer mount point for the A/C and the right side is modified to incorporate the XJ40 brake cylinder. Transmission tunnel is opened because of the starter motor too. Additional holes are made to the bulkhead in order to get more air flow from the heater box. All the holes are visible in photo taken before soft insulation was glued with PUR body glue. 


Jaguar Mark 1 wood veneering The Jaguar 2.4 litre Saloon is rich in wood. The notable feature not seen in other models are the wooden window cappings. Veneering the curvy forms of these takes some tolerance.

Useful advice for reveneering is available here.


Jaguar Mark 1 electrical wiring The task to rewire the car for the new needs was quite an accomplishment as there is not much room behind the dash. A/C, ABS, ECU, sound system, electric windows, central locking etc all have their needs! The dash is much simpler in original configuration. The A/C uses the same piping as before and additionally the square transverse member under the bulkhead. The left air outlet from a XJ40 is seen in this photograph between the dash and the parcel tray. 


Jaguar Mk1 brakes Behind that refined spoiler there is an oil cooler and old style horns. Note the other subtle design feature; the X300 side repeaters properly forced in the panel.

New proper jacking points were added in the good Mk 7 style. These stiffen the body too.


Jaguar xj40 sunroof in Mk1 The electric sunroof actually reinforces the car! The head room inside is very satisfactory. Should have been a standard item as in Mark VII. New headlining was naturally necessary. In the middle the Defa heater control is visible. Works as outside temperature gauge too. Thin insulation between the roof and headlining was added too similarly as in this Mk2 restoration project 


Heated backlight in Jaguar Mk1 The Mk I will be driven all the year so some winter fixtures there must be. I took the old rear window to a car glass company, they used it as mold and a new backlight was ready with in between laminated heating wire.  


Jaguar Mk1 boot The battery had to be moved back because the room was needed for air conditioning. A lid hides the battery, the CD changer, reserve petrol canister and the huge 12" subwoofer in the middle.

Compare to the Mk I original boot.


Jaguar Mk1 fuel filler lid One of the very useful mods is a wire controlled latch to the petrol filler door. In side the box there is the main switch for electricity. Sensible option if you want to avoid battery drain due to antitheft devices and car clock during long parking


Jaguar AJ6 engine in Mk1 Everything fitted in although the  original 2.4L XK engine was smaller! The pipe from the blower fan at right to the A/C box at left is not connected yet. The heater element is also fed with another fan underneath the right wing taking fresh air through the right side round intake. 

The original engine bay offers more space for fiddling. Had I wanted an even sportier car the recipe had been more controversial; a Tremec 5 -speed manual connected to the original engine with turbo-charging. In this way the  short stroke unit, having a very potent  head (with D-type valve springs), would be a really wonderful  adrenalin injector. 


Jaguar Mark 1 Saloon The subtle front spoiler fits to the car so well that one wonders that maybe Jaguar just forgot to fit it. 

MWS bolt on wire wheels are used in the summer time. They can handle the increased weight and performance. It is a pity that 16" wire wheels with the correct off-set of 33 mm are not available. They would fit this car excellently. 


Fifties Jaguar Saloon cars So finally the re-manufactured car was ready to meet its stable mate, the old lady in red. Appropriate JAG-57 register plates were a nice touch. 

The Mark 1 series was launched in 1955 at the Motor Show. It was designed to fill the gap between the large Mark VII saloon and the sporty XK series and to appeal to those who found the XK 140 too restrictive for family motoring. It took its styling from both of these cars - the XK150 for the front and the Mark VII for the rear of the car. Mark One perfectly fitted to the sporting compact saloon market - yet virtually untapped in the fifties.


Mark I and S-type side by side At first sight the Mk1 and S-type resemble each other. However S-type is wider and higher and clearly bulkier than the old lady. Making the choice what to want is easy.  


Jaguars at autojumble This picture from an autojumble close to Turku in 2012 offers a comparison between the nose treatment of Mark 1 and Mark II. Many think that the Mark II is the prettiest of these two but looking at the cars from front does not support the claim. Mark I looks definitively more agrressive and purposefull than the later design. Looking the cars from side the winner will be Mark II - no doubt. 


After completion the first thing to do was to take a trip to Sweden in order to give the kitties some enjoyable moments together. The XK here is owned by Sten, more about his cars here.

Now after the re-manufacture this classic compact saloon is once again as competitive as it used to be 50 years ago. The powerful AJ6 engine gives similar or better performance than XJ40 as the aerodynamics of Mk1 is better.  The XJ40 driveline is sweet and durable. No wonder that the AJ6 engine has been retrofitted to many older classic Jaguars.


Range Rover Sport and Jaguar Mark I side by side The massive Range Rover Sport -2010 and the Jaguar Mk1 -1957 are an odd couple but both are very inspiring cars.


Jaguar Mk 1 Saloon Grille Now the Jag has got a purposeful grin and strong stamina. Inside the grille a Kenlowe fan is hardly visible. Sir Lyon's biggest design flaw, the lack of proper spoiler in the 50-70's small sedans is fixed.

The Mk 1 looks is clearly more aggressive and nicer compared to or Daimler 2.5 litre V8. The sportier character is evident and the real performance due to modern technology lives up with the expectations. It is actually little better than for the 3.4 litre of its time, which was indeed very capable and faster than Mk2.


D-type wheels in Jaguar Mark 1 The Mark 1 is being driven the whole year through. For winter use D-type look-like wheels were made by Realm Engineering. They make a close to perfect fit (16" had been even better!).

The original rear wheel full covering spats were cut and  a modified Coomb's style sportier treatment was designed and integrally welded.


Jaguar Mk1 side mirror The side mirror fits much better to the door than on the front fender. This item in bought from Holden but the quality is seemingly traditional British. After four years of use the silvering is already damaged. The manufacturer has not treated the back of the mirror with appropriate paint. Had I known this I would have sealed the seams but now it is too late. This mirror has a straight holder. A curvy or inclined model had been even better for Mark I.  


Jaguar Mk1 rear seat XJ 40 front seats were re-upholstered with Autolux Connolly hide following the original pattern to match the original backseat's style. Left door's enlarged door pocket holds a fire extinguisher. The front doors were modified only slightly to incorporate bigger pockets than the original and KEF tweeters.

The picnic tables were not an original feature, they came to the Mark II - and these date back to Jaguar XJ40.


Jaguar Mk1 cockpit The original brochure for the 2.4 litre Jaguar Saloon shows an instrument panel with a glove box under the dash. This did not realize  in practice

As this central layout is much the same I already had in my Mk 7 I decided to go for something safer - too much wood very close to my nose here! Therefore I chose the 420 style in slightly modified form.

Other original MK 1 documentation is seen here


Modified Jaguar Mk1 cockpit The cockpit may please the owner's taste only. Mod. 420 style dash with original steering wheel and the Jaguar XJ40 J-gate. The instrumentation caused some difficulties (analog clocks but digital signal). The speedometer is a Jaguar 420 one with internals from ser III and using XJ-40 magnetic pick-up through an adaptor made by Robinson Instrument Services . Excellent system giving possibility to fine tune the reading according to different gearing ratios.


Jaguar Mk1 Enblem Jaguar MKI is beautiful. In its modernized, restored form it manages well the daily service year around. The robust AJ6 engine and the 4 gear automatic transmission fit perfectly to the car. In other words; it is not question about transportation only - we speak of an exhilarating driving enjoyment, the Mark I is back! 

The car's color is close to the charming original 3.4 L advertisement, which I use as background picture (note >2 Mb!) in my computer. 



Jaguar Mk1 underneath Some development was done to the Mark I chassis during the years. The front suspension using Jaguar 420 heavy duty springs became floppy and needed uppgrade. I replaced them with shortened Mark 10 springs which was a significant improvement. At the same time the Koni shocks were replaced with Spax items because the latter were easier to adjust.  I considered to replace the custom made 3/7" sway bar with a thicker one, but it proved out to be impossible due to lack of space.  My Mk1 which probably was one of the few Jaguars still using the self leveling rear suspension of XJ40 was getting too softly sprung in the rear and therefore I acquired a NSL Rear Suspension Conversion Kit from SNG Barrat. That fitted in place and cured the problem. To gein with my car had also rear silencers from a XJ40. These proved out to be totally unnecessary and they caused also problems with the road clearance. The current system where the intermediate pipe connects to the pair of silencers from where the exhaust pipes lead out to the right side of the car is perfectly silent enough.


Get away car Mark I Aino-Kaisa is one of the leading cross-country skiers in Finland. When she expressed her wish to enjoy travelling in a Jaguar from the church in Hollola to the nearby restaurant I got into problems as I did not have the formidable Mark7 wedding car any more. Despite Mark I being a compact saloon and the groom Tom  being quite tall we managed to fit in the car without bigger problems. Our get away car was very stylish from behind too.


Wedding We drove to the nearby lake for photoshooting session and Mark I felt very proud.


This Jaguar Mark I four door sedan conversion project resulted in a compact classic saloon, which is very silent, fast and easy to drive (much improved suspension and weight distribution). If the small saloon series would have been continued instead of switching to one model policy -  a car resembling this might have been true much earlier, in the 80's maybe! 

Jaguar 3.6 litre saloon specifications in short
AJ6 3.6 engine + catalyst, ZF-automatic gearbox, cold air inlet, Kenlowe fan, block heater, SS exhaust

XJ 40 (narrowed) IRS with ride height control, ABS brakes (optional). The rear springs were later changed with SNG Barrats JLM11698 NSL Rear suspension conversion kit

XJ12 Ser III front brakes, Mk II heavy duty springs and front sway bar, Koni shocks. The springs were later changed to modified Mk10 springs and the shocks to Spax because of easier adjustment    

Air conditioning with two fresh air inlets, heated backlight and XJ40 electric front seats (heated) in MK1 style

Electric Windows + XJ40 Sunroof, Central locking + Theft immobilizer

Six loudspeaker + 12" subwoofer sound system with CD changer in boot

205/15-70 tires on 15" bolt on MWS wire wheels

Very stiff body (widened rear) painted with Jaguar's Titanium - color. Modified 420 style cockpit.

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If you have questions about the car, please have a look on the Introduction - page, where my contact information is.    

XJ12C Rebuild
Mk1 Remanufacture
MkVII Restoration
XK120 Renovation


Other Mk 1 links: For other links see the links page

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