Anyone who has removed or replaced a rear bumper bar on a MK1, MK 2 , Daimler 250, Jaguar 240 and 340 series cars would be well aware of the problems of the 5/16 inch caged nut system used to secure the bumper bar to the mounting brackets. It is nearly a sheer impossibility to carry out this operation without the special caged nut which is a spring loaded boxed nut which sits in a slot in the bumper bar and to which the mounting brackets are bolted.
A club member in the country was in dire straits needing caged nuts to mount three rear bumper bars. He had tried every outlet to get these caged nuts but had been totally unsuccessful. It requires 8 of these nuts to mount a rear bumper
Back in 2001 I did some serious research into local sources and came up with a metric equivalent. It is an 8 mm caged nut and uses an 8X20 mm bolt to hold the bracket to the bumper. These nuts are readily available from Coventry Fasteners at 172 Lavarack Avenue, Eagle Farm [ph 3868 3655] for the grand price of 37 cents each and the 20 mm long by 8mm diameter bolts cost about 20 cents each. The Coventry part number is for the caged nuts is 26 8MCAGEN and the bolts are 26 8X20MZPBN
I contacted Coventry Fasteners and was advised that their computer showed negative stock. I have run across this problem before with this company and asked that they check the actual stock bins, Surprise! Surprise! They had over 100 in stock! A quick 10 minute trip from my workplace at Brisbane airport secured 30 for our country member and I grabbed an extra 10 for myself as every time you touch a rear bumper you can expect to write off some of the caged nuts due to corrosion.
Club members unable to get to a Coventry Fasteners branch can phone  3868 3655 ask for sales, pay by credit card and arrange delivery by whatever method desired such as by post or courier etc.
The Blue Mk2 gearbox was very stiff to change. Consultations with Ben Stafford the previous owner revealed that it had always been very stiff. He reminded me that he had actually broken a gear stick in my driveway some years ago and that I actually already owned the gear stick in the car when I bought it from him. I had lent him a replacement we had fitted on the spot so he could get home and had forgotten about it.
Ben suggested it might have bent selector shafts, which I had not heard of before, but he assured me it does happen. He had a few gearboxes in parts that he had acquired over the years. He donated a couple of gearbox top cover plates complete with selector shafts for me to try.
It took a short time one afternoon to remove the centre console, gearbox hump cover plate and remove the top of the gearbox. Note that BSF bolts hold down the top of the moss gearbox and not SAE/NF bolts as I expected. The already cleaned up and prepared replacement gearbox top cover plate was fitted and a trial run was made minus the tunnel cover and centre console.
The difference was immediately apparent and the gear gates could be felt and the gear stick easily manipulated. The “proof of the pudding” was when Ben dropped in one afternoon and I asked him to take the car on a trial drive. He agreed that it was a great improvement over the previous stiff system. I have not had time to dissect the previous selector system to find out what was the actual cause of the problem.
Ben Stafford had another problem with his 420. There was generally very poor oil pressure of only 20 to 25 PSI when hot and cruising on the open road that dropped back to almost 0 at idle. The engine did not sound "clapped out" and the oil consumption was quite reasonable. The electric oil pressure gauge was suspected but substitution of a hard line gauge only confirmed that the electric gauge was telling a true story.
I suggested that before he did any thing drastic like an engine overhaul he should check the condition of the oil pressure relief valve. I have had two occasions in Jaguars where low oil pressure was traced to relief valve problems.
Ben found that the oil pressure relief valve spring had been bent. This resulted in the valve itself sitting at an angle on the relief hole and a groove had been worn into the face of the valve. He used a lathe to clean up the face of the valve and subsisted a straight spring for the bent one
The results were fairly dramatic with an improvement to 45 PSI on the open road and 15-20 PSI at idle when hot. In his own summation of the situation he "was surprised that such a small gap in the relief valve had led to such a dramatic loss of oil pressure."
Whither goes thy oil pressure? (continued)
MY Mk2 3.8 Auto has had a slightly low oil pressure and I was a little concerned that the engine may have been "loose" i.e. getting worn. I took a trip to Ben Stafford's to use his hoist and get easy access to the pressure relief valve.
Upon removing the relief valve it became immediately obvious that the valve face was not seating properly. A quick trip in the lathe to face off the valve resulted in an increase of 10 pounds per square inch over all of the operating range.
However I now believe the real problem lies in wear on the upper flutes of the valve which allows it to sit in the bore of the valve body at an angle and the final solution will be to replace the valve itself with a new part and possibly even re-sleeve the valve body.
The rear axle of the MK1 and 2 is located on the extreme end of the rear spring leaf and is controlled by a torque arm on either side of the car running from a body mounting to a bracket on the axle. This then locates the axle in relation to the body and stops the spring winding up under acceleration torque somewhat like a trailing arm system. The torque arms are fitted with metal/rubber bushes and with age these deteriorate with a subsequent loss of “stiffness” in axle location and general handling suffers. Don't confuse the torque arm with the panhard rod, which runs laterally [across] the car from the right hand side to near the differential centre. It centres the rear axle and suspension.
On the red MK 1 I knew that these bushes were getting pretty bad. Every time I jacked it up I could see daylight through the rubber area of the bushes. I obtained a new set from Jag World [PH 3272 7287] and with some help from a friend who is a club member we removed the torque arms, pressed out the old bushes and inserted the new bushes. Note-I have seen an illustration of this operation in a UK magazine using a bench vice. They must be different over there because we used almost all of the force of an 8 tonne hydraulic press to get the old bushes out.
We also found that the right hand body mounting for the torque arm was cracked and required some serious oxy welding to repair before refitting the torque arm. It also helped that this fellow club member happens to have an electric/hydraulic two-post car hoist in his private shed. This made the job much easier.
There was no doubt that as I drove the red MK1 home that evening along a winding high-speed road that the handling had vastly improved
When it came to getting the white MK1 through a roadworthy one item that became obvious was that the rear shock absorber mount rubbers were completely perished and new rubbers would need to be fitted before it would pass. With that in mind I had the car on ramps at home and fitted the new rubbers by the time honoured system of lying on the shed floor and applying much grunting, effort and some amount of cursing.
Whist lying on the floor I recalled what Tony Herald had said about how he cleaned under his concourse car and thought why not start here? So I degreased and cleaned up the diff and the general areas under the spare wheel well and petrol tank area and subsequently applied some black paint etc. It sure looked better.
To my surprise when the car was on the hoist being checked for roadworthiness I noted that a patch of my new paint on the differential had been scraped back to bare metal. I then realised that the odd suspension noise that I had heard was not a noisy/squeaky shock absorber but was actually the differential occasionally rubbing on the body area immediately adjacent to the petrol tank. I did not point this out to the chap doing the roadworthy and he was more interested in tie rod ends etc. The torque arm bushes looked OK but more on that later
After getting the car registered I organised use of the previously mentioned club members hoist. Mark Miosge from North Qld. Jaguar Spares in Mackay [ph 07 4954 6003] had offered me a good deal on a pair of torque arms he had overhauled with new bushes for a customer who had never collected them. I had acquired them “just in case” I needed them. When we removed the old torque arms the bushes literally fell apart so what looked OK was in fact totally “shot”. The new torque arms were fitted with a subsequent improvement in handling and the elimination of the occasional squeak.
I have since noted that the red MK1 has a patch welded on the rear of the diff housing just where it would rub on the body. I presume this is an old battle scar from a previous occasion when the torque arm bushes flogged out
You don’t have to send a lot of money to the Poms to identify fairly closely when your MK1 / 2 was built. There is no doubt that the certificate they send you will give original details on the car which is nice to know but do you really need to know unless it is going to influence the concourse judges or increase the value of the car.
Upon being asked any question relating to age/build of one of these models I immediately reach for the Nigel Thorley “Original Jaguar MK1/MK11” book. This is an excellent publication and one of its endearing features is that it traces each model of car by dates of production changes to the assembly line.
Thus by knowing the chassis number and engine number it is possible to narrow down the production date to within a couple of months. E.g. the Mk 1 was in production from 1955 to 1959 and there were no less than 25 production changes, which average out to one every two months. These production changes are typically dated with a month and start off with “from chassis number so and so” or “from engine number so and so”. Simple arithmetic between the change dates and chassis/engine numbers will give an indication of the quantity being produced and from this you can make a reasonable estimate of when your car was built and more particularly what the production status of your car was all about.
Although this book is expensive at typically $59.95 it is the reference bible for anyone wanting to get their MK1/MK2 restoration correct and the colour photos of interior trim and changes in production are really good. The text is well written and is totally to the point. I.e. no padding-just information. I have read it several times and still emerge with some new snippet or fact that I have previously missed.
Another worthy publication is the “Practical Classics Mk 2 Jaguar restoration”. I wish I had read this years ago. It traces a project car that was professionally restored but at the same time as much as possible was retained from the original trim etc. For example it gives guidance on replacing the door trims by salvaging the original vinyl and attaching it to new backing boards. I have also used the same technique in MK 1s. There are literally dozens of photos of each step along the way and many hints and tricks are explained including how to find the hidden screws that retain trim and also woodwork restoration etc.
For the restorer of a MK2 [and a lot of the book also applies to a MK 1 particularly in the body and mechanicals] it is extremely useful and whilst not cheap at again $59.95 I believe the cost would be more than off set by savings made in the restoration process from the books recommendations on salvaging trim etc.
These books are available from any good motoring bookshop. The prices I have quoted are from a bookshop advertising on page 51 of Edition 101 the Australian Jaguar Magazine. There are also a number of other Jaguar models covered by the "Original " series of books as well as the "Practical Classics" publications. If they are anywhere near the standard of the MK2 publications they should be good investments. You could also enquire with our club librarian as to their availability on loan from the club library.
A number of club members have get involved in the ride height debate for a MK 1-2 Jaguar. It appears that 18 1/2 to 19 inches from the ground to the centre of the boot lock is about right.
However members of other registers have also done investigation into their cars and have found some to be well and truly in need of serious adjustments and repairs to the rear end. Malcolm Imrie who wrote an article for the Bits and Pieces section of February magazine on XJ6 rear springs provides a good example of “getting it right”.
The MK 1&2 Jaguar workshop manuals are a little skimpy about ride height for the rear end of these cars. Everybody knows that the correct height for a front end is about 3 finger widths between the top of the tyre and the bottom of the mudguard arch. In the workshop manual there is a specification for the amount of curve in the rear springs but that is about all.
It was not until I had the two MK 1s in the shed that I noticed there was a completely difference in the way the cars appeared to “sit”. The red car was definitely lower in the rear end. With a tape measure I checked the height from floor level to the centre of the boot look . To my surprise I found a difference of 2 ½ inches. The red one measured 16 inches and the white one 18 ½ inches. The difference really becomes apparent when you realise the red one is on standard 185x15 tyres and the white one is on 205x65x15 tyres that have about ½ inch less in tyre profile height.
I would appreciate any feedback from MK1 and 2 club members on the specific height measurement on their cars along with the types of tyres fitted. We have checked another club members MK2 and it appears 18 ½ to 19 inches to the bootlock centre is about right on 185x15 tyres.
I always thought the red car looked to be “dragging its bum”. Once I have established the correct height it is off to the spring works for resetting
With two MK1 cars with sagging rear springs it was time to adopt production line methods. Mark Miosge from North Qld. Jag spares in Mackay [ph 4954 1420] mentioned that he had a good pair of springs and offered them at a reasonable price. In fact the freight was nearly as much as the springs. Inspecting them on arrival showed that they were good and did not require any re-setting. I visited Barry the friendly spring man at Pine Rivers Spring works [ph 3285 7383] and got him to fit the new spring eye bushes and rubber mounting blocks that I supplied.
A couple of hours under the car including welding up part of the left hand spring mounting box and the red MK 1 3.4 was back into action. It really does sit correctly and this is emphasised when the two red MK1s are sitting adjacent to each other. There is a really apparent rear end sag in the 3.8 car. The springs that came out of the 3.4 will be re-set and have new hardware fitted before going into the red Mk 1 3.8. I will then have a spare set of rear springs so if anyone is desperately in need of them contact me.
I have been intrigued by an on going problem in the 1960s model Jaguars such as MK 2, S type, E type, 420 etc. The main area of concern is the oil pressure gauge. This is an electric device that was apparently Smiths first foray into the domain of electrical transmitted oil pressure. Apparently the Jag Enthusiasts Club in England has also been following up on this problem.
To say that the Smiths electric oil pressure gauge is an accurate instrument would be taking the truth very lightly. It is one of the most Heath Robinson devices I have ever encountered in any instrumentation. Normally an instrument transmitter contains a device a bit like the variable resistor used in volume controls in a radio. These are generically referred to as "potentiometers". As the temperature or pressure changes the variable resistor feeds more or less voltage to the gauge in your dash panel to make the indication. Simple enough?
However Mr. Smith put a whole new twist on the scene by using a system in his oil pressure transmitter that works as follows. The flexible diaphragm in the transmitter has an electrical contact on the diaphragm. When oil pressure expands the diaphragm this contact connects to another contact on the end of a bi-metallic strip. This makes a circuit through a heating wire wound around the strip which heats up until the bi-metallic strip bends and breaks contact with points on the diaphragm.
The bi-metallic strip then starts to cool down and straightens out until contact is made again and the process repeats. The more oil pressure there is the longer it takes for the strip to heat up and therefore the more electric current runs through the system. This current is measured and shown on your oil pressure gauge as pounds per square inch!
The bi-metallic strip system is well known and is used in the majority of "flasher" units in directional indicators in motorcars. However they do not last forever and eventually they fail due typically the points burning out. It is an electro/mechanical device and as such will never be a stable source of information for a gauge system.
Why I am making this point is that an old oil pressure transmitter can give quite erroneous readings. One club member was really quite concerned with his oil pressure in an XK series motor in a MK2, which only ever got to about 40 PSI cold and was flat out making 20 PSI when hot. The engine was generally in good order and was not rattling or giving any typical signs of distress associated with clapped out Jag engines. On my suggestion he obtained a direct reading after market gauge and coupled it up in place of the electric system and was delighted to find that all of the above pressures were just about doubled.
I have also run across this problem and have had widely divergent readings from different transmitters. In fact I trust the older Bowden Tube direct reading oil pressure gauge used in early Jags like the MK5, 7, 8 and MK 1 any day against one of these later electrical devices.
The good news is that a company by the name of CAREBONT in England have purchased the rights and tooling for early Smiths gauges and have redesigned the oil pressure gauge for these 1960s Jags. This kit apparently consists of a completely new transmitter and gauge using modern techniques but looks just like the original. It is not cheap at around 70 pounds or about A$200 [Australian] dollars but the current price for a new oil gauge transmitter to fit the old system is A$130 so it would be worthwhile going the extra dollars for something new, reliable and accurate.
To get things into context you must remember that Sir William Lyons was attempting to break into the domestic sales area of the UK market when he first came up with the small 2.4 saloon which subsequently became known as the Mark 1.
At the time the Mark 7 was in production however it was viewed by the British as a large car. In fact the Mark 7 was aimed squarely at the export market as steel supplies in Britain were still rationed under a quota system. You could only get steel if you were in the export trade.
Sir William was no slouch in recognising that he needed a car which would be acceptable to the home market as being reasonably economical, fast and still be of a size easy to manoeuvre and park in the congested streets of that island continent. He also had to consider that in the UK domestic economy petrol was very expensive. Petrol rationing had only ceased in 1952 and nearly returned in 1956 during the Suez crisis.
It should be noted that in 1955 when Sir William introduced his MK 1 Australia was involved in a love affair with the FJ Holden which only ceased production in late 1956 It’s replacement which was the FE/FC series Holden was no faster. Sir William gave the world a twin overhead cam vehicle producing 112 Horsepower out of 2.4 litres or approximately 144 cubic inches, which did 100 miles per hour and easily did 100,000 miles without any overhaul. What General Motors sold to Australia was a vehicle called an FJ Holden with approximately the same capacity in a pre war pushrod GMH engine design that produced 60 HP, did 83 MPH and had a life of 50,000 miles between overhauls if you ignored the gudgeon rattle which started at 20,000 miles. In those terms alone the 2.4 Jaguar was no slouch. You could not compare the brakes and handling. The Jaguar was so far in front that it is like comparing a T model Ford to a post world war 2 car.
Anyone who has owned a 1950s British car will understand that the British paid slavish attention to fuel economy. The MK1 2.4 was no exception. It had a deplorable pair of Stromberg downdraft carburettors to miserly feed the fuel into the engine and a whimsical narrow tailpipe/exhaust system to get rid of the gasses. The early model also had very small valves. After all that, it is remarkable that the car did so well as to make 100 MPH. Some British reports claimed an economy of 26 MPG however in practice 22 to 23 MPG from a MK 2.4 is more realistic. By the way the MK1 2.4 was officially about 2MPH faster than the MK2.
Many 2.4 Jaguars imported into Australia are also saddled with automatic gearboxes, which further reduce performance. The old DG [Detroit Gear] series box, which is really, a Borg Warner 35 series in disguise does a good job but is very wasteful in power. They are also notorious for developing oil leaks.
What Are They Worth? Currently 2.4 litre sedans are very cheap and even an excellent example only brings a fraction of the value of a 3.4 or 3.8 litre car. I note that The Australian Jaguar magazine [edition 91] quotes
MK1 2.4 $1000 to $20,000 MK1 3.4 $1000 to $25,000
MK2 2.4 $ 2000 to $20,000 MK2 3.4 $3000 to $30,000 [3.8 $3000 to $40,000+]
The April edition of Australian Classic Car is a little more circumspect in quoting top price for a MK1 2.4 as $11,500 and a MK2 2.4 as $14,000 while the top price quoted for a MK2 3.8 is $29,000.
Better Brakes? Having faced up to the fact that a 2.4 litre sedan will never be worth as much as a 3.8 you still have a number of options if you feel that you want more performance. However before we go down that route there is one important aspect to remember particularly if you are dealing with MK1 sedans. It is no use making it go faster if you can’t make it stop. The drum brakes on a 2.4 sedan are “adequate” but on the MK1 3.4 are generally acknowledged as being at or even getting beyond their limits. If you are going to increase power then you should give serious attention to the brakes. There are kits available to install later series Jaguar disc brakes to the front of a MK 1 and I recommend you get in contact with suppliers such as Geoff Widdicombe , GBC, Jag World, British Cat Components and Don Milliner all of whom advertise in this magazine for advise, expertise and general cost of this conversion.
Heart Transplants Some of your power options include an engine heart transplant. If you can access a MK1/2 3.4 or 3.8 engine this is a simple and relatively cheap way to go. Unless the chosen transplant engine has really major problems you should be able to fully overhaul it for somewhere around $2000 to $3,000. If you are a do it yourself person you may get out of it much more cheaply. 4.2 motors are quite plentiful however you may have problems in sorting out engine mounts pulleys and other accessories.
I note what looks like a late model [4 litre?] fuel injected engine under the bonnet of a MK 2 in edition 91 [page 69] of Australian Jaguar. I also knew of a MK 1 with a Holden 179 engine, which lived in inner city Brisbane and regularly towed a trailer to the family weekend farm. Jaguar also put a V8 Daimler engine into the MK 2 body shell and called it a Daimler 250. From that point of view your options are pretty open.
Staying with the 2.4 and originality. A relatively cheap way to go is to look at the upgrades available on the 2.4 engine. Jaguar did offer a number of options in both manufacture and aftermarket products so you could make a number of improvements and modifications and still be “original”. It is worthwhile noting that Jaguar quotes the following HP figures of MK1/112 hp: MK2/120hp and 240 saloon/133hp. The 240 was fitted with the 13/4 SU carbys.
If you have one of the very early 2.4 engines it has small valves and as such the head is hopeless for any upgrade in power. A “B” series head with the larger valves and higher lift camshafts is needed. These are amazingly plentiful once you start looking as the majority of later 3.4 motors had them. Experts talk about “C” and “D” heads but they are rare, expensive and probably an overkill on a 2.4 engine.
Along with the B series head a MK1 or MK 2 3.4 intake manifold and SU HD 6 1 ¾ inch carburettors along with the starting carby are needed. These should preferably come off a MK1/2 3.4 or 3.8 engine. That will allow you to use standard plumbing for the cooling system and standard carby linkages. Another possible source is the S type sedan. The original 3.4/3.8 engines used a thermostat to control the starting carby. Most owners have modified them with a switch under or in the dash panel to allow direct control of the starting carby. One cunning place to fit such a switch is a push off/pull on switch fitted in the bracket just above the bonnet release knob and operating in a parallel direction with the knob. Somebody had done this to my MK 1 “hotrod” and you cannot see it or find it without being in the “know”.
Finally the crummy little narrow single pipe exhaust system used on the 2.4 should be replaced with the 3.4/3.8 dual exhaust system or at least a much-enlarged single pipe system. Note that the 2.4 exhaust system will not fit a 3.4/3.8 engine, as the increased height from below the vehicle to the exhaust manifold becomes a problem. There is about a 2 to 3 inches difference in pipe length due to the deeper motor, higher block and increased depth to get below the vehicle floor.
Jaguar also recommended 9:1 pistons. In view of the current environmental lobby and phase out of leaded petrol this may not be the best way to go. 8:1 seems to be about the limit for compression ratio with modern fuels and old engines.
With all of the above modifications including the 9:1 pistons it is suggested that an overall increase of about 45 Hp was possible. This would put the modified 2.4 engine at about 157hp which is pretty much the same as the original 3.4 engines rating of 160 hp as fitted to the XK 120 and MK7 sedan. Even without the higher compression pistons 20 to 30 HP should be achievable and would make a significant improvement to the performance of a 2.4 saloon.
Cooling the engine. I have had queries as to whether the 2.4 radiator would need modifying. As yet I have not been able to establish any difference between 2.4 and 3.4 radiators. I would suggest that if you have a marginal 2.4 engine that tends to overheat you would have problems if you did anything to increase performance. It would be best to have the radiator cleaned at least. John McDonald from Stafford Radiator Service who advertise in this magazine assures me that standard cores are readily available and special high capacity cores can be ordered for cars with specific problems such as air-conditioning added on etc.
If you have an early MK1 2.4 with a cast alloy four blade fan remove it and replace it with a late model MK 2 multiblade fan. The 4-blade fan is hopeless in the Qld. environment even when the engine and radiator are in perfect order.
Getting rid of the Slushbox [Automatic Gearbox] As previously mentioned the DG automatic gearbox is does waste a significant amount of power and ultimate performance will only be gained by replacing it with a manual gearbox. This is serious stuff as there are numerous areas that need to be addressed in such a conversion. [Been there - done that]
The simplest approach is to get a MK1/2 manual [moss] box and bell housing. However an engine previously used in an automatic car will need a flywheel and clutch plates. A slave cylinder, a different [single piece] tailshaft as well as a manual pedal box setup with clutch master cylinder and flexible lines will also be required.
There are also a number of other Jaguar manual boxes available however the gear lever position might take some working out as well as gearbox mounts. Don’t forget or overlook other conversions such as the 5 speed Toyota Celica box conversion developed by Ron Moore.
Differential ratios I refuse to enter this minefield. There are undoubtedly experts out there who may be able to assist. Limited slip differentials and their ilk sound great and have their uses but I think you need specialist expertise to get involved in those areas. If you have a diff that works OK for you then leave it alone. If you need some better ratios after a heart transplant the find out what original type was fitted to a 3.4 or 3.8 vehicle and use that as a starting point.