5.3 V12 Engine (stock)

Here we have the stock Jaguar V12 engine, which will be used during the first season for the purpose of licensing runs. This also provides an opportunity to see just what you can get out of the stock engine, by removing a few power drains, bolting on a few additions, and doing a little tweaking.


Engine Specs: Stock

Type: OHC V-12
Displacement: 5343 cc / 326 cu in
Bore x Stroke: 90.0 x 70.0 mm (3.54×2.76 inches).
Compression ratio: 12.5 : 1
Hp @ rpm net: 295 @ 5,500 rpm
Kw @ rpm net: 220 @ 5,500 rpm
Torque @ rpm lb/ft net: 320lb @ 3,250 rpm
Fuel Injection


The first order is to remove a bunch of dead weight and power drains. First to go is the air conditioning compressor and all the associated lines valves, belts and brackets.  The air injection pump, lines, idler pulley, and engine fan assembly were next to go.
 The removal of the air pump necessitated the removal and closing off of the air line ports in the intake manifold.
 A member suggestion from Jag Lovers worked perfectly.  Using anchors to close off the holes provided a neat finished appearance.  One note is that I wouldn’t bother trying to use the previous o-rings on the anchors. I found that setting the anchors simply squeezed the o-rings out anyway. So, a dab of high heat silicon did the trick nicely.


The engine fan when removed displayed numerous cracks and fractures.  I’m somewhat surprised it hadn’t come apart at speed already.  There will be a pair of electric fans going in to keep the air moving.  This, in addition to the removal of the air conditioning compressor will allow for much improved air flow through the ‘v’.


The most readily identifiable impact of removing all the dead weight, without making ANY other changes, was the increase in the idle speed by about 1000 rpm. Throttle response is notably quicker due to the dramatic reduction in rotating mass.  Total dead weight removed, JUST from the engine, about 75 pounds.  I’ll throw a rough estimate of 35 horse power gained in this process, which would be related to airconditioning turned on etc.  Some changes in pully diameters can easily free up a few more ponies.


The ignition system in the Jaguar V12 is well known for it’s difficulties, many of which were spawned by the levels of heat the distributor, amp and wiring were exposed to in the ‘V’ of the engine.  Heat soak was a real issue.
Many a V12 distributor advance siezed up completely due to this, and the incorrect grease from the factory.  (see, no one is perfect)  Any V12 our there with a few years under its belt, has wiring in the valley that is as brittle as crazed glass.  This particular car is no exception.  At one point after stripping off the excess components attempts to refire failed.  This was eventually tracked down to the wiring connecting the amp, still mounted in the original location.  A simple ‘jiggling’ of the wires got the car running again.  This, along with the heat effects on the fuel lines to the injectors is likely the root of many an engine fire, which as you may already know is not an uncommon occurance.  The final version will see the entire distributor, coils, engine and fuel injection management replaced by a computer controlled system.  THAT should see the end of the ingnition system nightmares.


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