CORTANA

CORTANA

After 500 miles we call the engine run in. The last 50 or so of those were given some serious grief, we tested the car to at least 13mph, and the motorway acceleration was superb. The fast lane hogs don't seem to expect a Jag to actually be pressing on, but they do seem to shift out of its way.

Anyway, we want the engine now, so once again a perfectly-servicable X300 drives into the garage and loses her engine.

The engine whistles itself out much faster this time, and in a single day one comes out and another jumps in. The new unit is, however, an AJ6 the Bear has rebuilt. Originally retired in 2007 at Mallory Park with a blown head gasket, he took it apart and discovered a ruined crank, thoroughly worn shells, not a big end left in it.

With a dollop of Bear cunning it gets a bore hone, complete new bottom end including a shiny crank, and all back together. Making it fit into an X300 is not tricky, but making it run is. Got to change the exhaust manifolds of course, but the cam cover is a headache. The X300 runs coil packs, the AJ6 cover doesn't allow for that. The only solution is to fit the AJ16 cam cover to the AJ6. And it doesn't. Only three bolt holes line up. Thanks Jaguar.

The answer is simple. Hold it on with only 3 bolts. It's only a road car.

600 miles later, no oil leaking from it, so it was clearly good enough!

The transplant turned around in a day, the car goes straight back into service. We do like the gearbox mounts on the 300, we approve. If only the guy who did the mounts had been allowed to design a bit more of the car.

Why are we rebuilding and running in an AJ6? Well, we plan to sell it. It's effectively a brand new engine. New crank, bearings, chains, skimmed head etc, it's as good as it gets. Well, we had to do something with our AJ6 stockpile, we don't race them anymore. Others do of course, and there a few asthmatic 3.6s still out there. Someone will want this.

So a 1000 miles to run it in, and then it'll be coming out again. And then we'll plug in another 4 litre AJ16. To run in.

With the arrival of a higher-spec X300 we will obviously be transferring a few of the tasties parts across to upgrade this one, the new car has "race me, race me" pretty much written all over it.

ENGINE TRANSPLANT - AGAIN

Shiny parts. We don't usually see many of these.

4 litre AJ16 in the morning, 4 litre AJ6 in the evening.

RACE ME

RACE ME

RACE ME