A jaguar called Alfred
Overview
It all started in the pub one Friday night . talking about cars . motorsport and driving fast and then somehow Bonneville found it’s way into the conversation and I was hooked
It was always going to be a classic jaguar , but the iconic v12 engine wasn’t going to be up to the job ,I needed something bigger with a lot more torque
I knew jaguar had built a prototype quad cam v12 back in the late 50s for racing ,and I needed one . but a bigger one , I decided to build one from scratch
here’s the story
Jaguars original Quad cam
Why and how and how I built the engine
Inspiration for this build came from Jaguars legendary 5 litre quad cam engines of the early sixties .fitted to the only prototype le.man car ever made code named XJ13 now wearing fuel injection but originally fitted with six su carburettors
Since I knew the old xk cylinder heads will not fit on a std v12 block my first thoughts were to make a engine block mould and have one cast ,after a discussion with the foundry and pattern makers this idea became the most expensive route and was quickly dismissed
After designing and the making a Mdf model of the crankshaft casing The idea of using plate steel instead of a casting seamed the best approach,I went to see some industrial fabricating friends who agreed it’s viability and
Initial drawings were sketched then transferred to Cad
And the 45mm plate steel was cut within 1 mm tolerance
With All the pieces roughly machined and then tack welded together and tolerances checked more times than I can remember , the now very heavy casing was taken to some very clever roller coaster engineers where complex welding codes were formulated and the whole thing was welded up beautifully
It was then put into a computer controlled oven for two days to relieve and destress the metals before numerous hours of machine work commenced
As this was taking place the two engine blocks got crudely sliced off at the bottom of the cylinders and then machined to match to the now completed crank casing ,
The xj6 crankshaft was machined a little wider on the journals to accommodate the two machined connecting rods to run on the same journal , calculated brass plugs were fitted To seal the original crank oil ways and two new oil galleries per journal were machined in ,the crank was then lightened ,knife edged ,balanced with lightend flywheel and weight calculated custom front pulley all polished then reground and installed into newly inline bored crank case with new bearings, all the running clearances were double checked with trusted engineers blue duringassembly
The 12 machined ground connecting rods were all polished and balanced along with the pistons ,rings, clips and gudgeon pins
The two blocks now fitted to the crank case with high tensile stainless steel studs and the rods and high compression pistons installed in usual manner ,with the overbore this brings the cubic capacity to 8.73 litres
As the right hand side block sits further back to space the cylinders , rods and pistons ,the front face of the block was extended forward
New timing chains were lengthened and an oil fed chain idler gear designed fabricated and fitted along with an oil fed tensioner and chain guides using and modifing as many jaguar parts as I could
The original distributor drive was modified along with a high capacity oil pump / pickup and delivery plumbing with external oil galleries
The oil sump now has a few subtle bumps to clear the redesigned oil pump location
The right side cylinder head had the front timing cover extended to match its block along with extended rocker covers
The left side head is more complex requiring reversal to allow exhaust and inlet ports to mirror its neighbouring head
This required the front and rear of the head to be removed rotated 180 degrees and re welded machined and surface ground,the heads now fitted with the larger fuel injection camshafts then have to be swapped over and refitted with new oil feed and drain galleries machined
Both heads were flow ported and refaced installed and cams carefully dialled in
As I always intended the engine to run on carburettors an intake jig was made to fabricate two identical manifolds with integral water galleries
Carburettor linkages were made to allow for a light throttle pedal feel a must with several carburettors all linked in unison
The distributor made up of parts from both 6 and 12 cylinder along with custom ignition leads send the sparks to the relevant cylinders
A custom made bellhousing plate was made to move the starter motor to the location needed and to bolt the getrag 5 speed gearbox
The rear axle has modified crown and pinion carriers to accept the tall gears which I can only hope we calculated correctly
A engine test bench was fabricated and the engine plumbed and fuelled ready to fire up
Huge disappointment followed as it would not fire ,and at one point this huge engine nearly became a oversize coffee table
A high output ignition coil from MSD cured the problem and the engine fired instantly then setttled to idle
I don’t know the weight of the engine but it is extremely heavy ,chassis modifications and double engine mounts ease the stresses
If elvington is not long enough to achieve the desired top speed
There are plans to ship the car out to Bonneville salt flats this year
