Leaping Jaguar


Back in 1989 one of the previous owner, a lady no less, invested in an expensive mechanical rebuild, including a brand new engine from Jaguar.
This engine resides today on my XJ12 SII, taking me all over Europe but still with barely 13k miles of usage. So nice was this engine that Chris Coleman from Jaguar Workshop commentated it was the nicest V12 running motor he has seen in a long time with Nick from JagShop (an XJR100 owner) remarking how fast it was, pure sex on wheels!

So I was left with similar V12 from the SII to install in my SI. It did run sweet but felt quite lethargic compared with the SI engine. With a confirmed 37k miles of use it was in a good condition apart from the bodged attempt to repair the rear crankshaft seal. If you own one of these mammoths, remember to run the engine a couple of times per month or more as you risk the seal ovalizing from a stagnant crank applying its pressure in the same spot.

Unfortunately, with the engine sitting in a workshop bench with its coolant drained accelerated head studs corrosion, allied to years of neglect, it was truly a horrible task to remove the head. My father; a mechanical engineer; was forced to produce a very sturdy tool comprising of 12mm thick plate with hardened studs to induce the head to move through the corroded studs. This was made worse by the catalytic corrosion between the alloy head and studs steel. After a week of hard graft and copious amounts of Wurths Rost Off, finally the head parted company from the block, revealing the corrosion extent, with gaskets completely rotten and serious surface corrosion on the heads' faces.

Kindly, Chris Coleman agreed to sell me a pair of flat head in excellent condition for a very reasonable sum, needing only 0.10mm re-facing as a matter of precaution.

It took me over 60 hours of slaving to clean the engine block as the filth was truly engrained and I'm not fond of sandblasting engines or other delicate mechanical components as grit can deposit itself in inaccessible places, causing havoc later, ruining a freshly rebuilt engine. So I've used a very powerful detergent used to clean trucks, I ruined the skin in my hands as it started to peel off, so a sound advice is always to wear proper gloves, goggles and proper clothing.

Remarkably, bores, crank, rods showed little wear, confirming this engine sturdiness.

By this time, I started to fancy the idea of tuning this engine for fast road/sports specification, reading many technical books on this subject including the excellent manual from Graham A Bell and the SAE booklet written by Wally Hassan describing in detail the V12 development work.

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