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Jaguar MK2 Vented Disc: BRAKE CONVERSION OF 1968 MK2 JAGUAR FROM SOLID ROTORS TO VENTED ROTORS

UPGRADES AND IMPROVEMENTS | Mike Roddy Motors

Zeus Engineering

 

checked brakes yesterday front are 4 pot zues and back are standard dunlop ,cleaned pads and rotors havent tried it yet,,, brakes were ok but not as good as my nissan patrol will try it today ,,,found i had no brake lights the switch is at back of motor cant get down to it ,managed to get wires off there is power to them thinking its the switch could never get to it without pulling motor out wondering if i could put another switch inline at booster

 

Lofty,


I used Complete Custom Wheel, three piece rims so that I could get the custom off set which enabled me to run 17" x 8.,5" with 245 40 series run flat Bridgestone tires LM20 - 3PC - CCWheel


Here is another brake upgrade for the rears if you want to go all out
JH Engineering - Caliper Catalogue

 

I'd be upgrading the rear calipers to a modern billet alloy replacement, better ability to dissipate heat, modern seals, and 50 years newer, as well as checking all the brake lines conditions, I'd assume they were all replaced at time of the conversion, but a set of braided lines these days can be custom made pretty cheaply, and will help with pedal feel.

However it is evident the master cylinder setup has been drastically changed from factory with the second setup on the passenger side firewall with an additional booster fitted, it's just quite possible the master cylinder is sized incorrectly to suit the 4 spot calipers fluid requirements, that could be all that is wrong, or you could have glazed pads and rotors, are the front rotors solid or vented?

Also, the stud pattern is 5x120.6 or 5x4.75", chevy wheels have the same bolt pattern, early Holden stuff like the HQ does as well, there is a fair few styles of wheels available with different offsets off the shelf, as for what offset and width you require to clear the guards, a bit of trial work would be required.

As a quick indication, I had a set of BMW wheels that I could fit/mock up, but never ran due to being 5x120, the specs on them were 16x8.5 +10 offset, fit the rear perfectly, but sat outside the front guards by about 10mm.

 

changed brake switch to one that works off peddle all is good there now ,,,,yes pads and rotors could be glazed i used brake cleaner and sanded pads still havent given it a real trial .,brakes feel hard just need more pressure then modern to push,, not sure on stopping distance yet ,,,if i put 4 pot on rear would i need a proportioning valve ,after market what brand or maybe xj6 on rear,,,, brake master cyclinder is the original they just added a remote booster,,,, ,so you say braided line from wheel fitting to caliper would help with peddle feel,, previous owner only did 1800 klm ,lines are original

 

XJ6 is a straight bolt up option.

Original rubber brake lines can flex/swell under pressure, fitting braided replacement lines can eliminate that, meaning all the fluid is transferred to pushing the brake calipers rather than losing some pedal feel due to the fluid filling the expanding rubber hoses.

I'm unaware of 4 spot brakes for the rear end, anything is possible though with enough money and skill thrown at it, however most of the braking is done on the front end, roughly 70% due to weight transfer, so that would be my focus point on getting the brakes to a satisfactory level, suss out the master cylinder size and then compare it to the surface area of the pistons, and go from there.

Other things that can effect pedal feel, can be things like worn ball joints or loose wheel bearings that might wobble the rotor in relation to the caliper and push the pads back, this however usually results in a soft pedal feel requiring a double pump to get a firm brake pedal.

A car of this calibre, I would suggest a complete going over from the front to the back, its 50 years old, had had large modifications done to it, and only driven as you say 1800kms, quite possible the bugs haven't been ironed out since the conversion, or some things might not have been done to a satisfactory level.

 

Any updates on this car?

I've sold all my Jaguars apart from the complete running one, and I just picked up a 2JZ and auto off a mate for next to nothing.

Any chance you could send me some pictures of the engine mounts and trans mounts. I've got an idea on how I plan on doing them, but it's always nice to see how others have done it.

The 2JZ is 200mm shorter in length and not as high as the XK 3.8, so it's going to have a much better weight balance front and rear compared to original as I can mount it low and rearward, also the XK engine is about 270kg down to about 220kg with the 2JZ.