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Jaguar XJ12 SI
Restoration
Block
Heads
Fuel
Exhaust
Gearbox
Handling
Bodywork
Electricals
Interior
Engine
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.
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.
Racing exhaust manifolds have been produced by my father, insulated in a special exhaust wrap , fitted by Jorge (who's allergic to fibrerglass) trying to reduce under bonnet temperatures. To clear the Mercedes A class electrical power steering pump, the new NOS radiator had to have its inlet neck modified by bending it 30 degrees. Samco water and vacuum hoses were used throughout, for longevity sake.
K&N air filters, courtesy of AJ6 Engineering have been fitted. I did indulge in a bit of glitz by chroming all solid pipework in the engine bay, air filter boxes' lids and even the engine bay top struts. Opening that bonnet always makes my day shine!
Many clamps and other simple brackets were reproduced in stainless as originals were very rusty and unsightly.
It has been a learning curve what can work and cannot, throwing some pleasant and not so pleasant suprises.
For a more detailed insight and photos of the work carried out, please click on the buttons overhead for details concerning block, heads, fuel, exhaust and gearbox.
K&N air filters, courtesy of AJ6 Engineering have been fitted. I did indulge in a bit of glitz by chroming all solid pipework in the engine bay, air filter boxes' lids and even the engine bay top struts. Opening that bonnet always makes my day shine!
Many clamps and other simple brackets were reproduced in stainless as originals were very rusty and unsightly.
It has been a learning curve what can work and cannot, throwing some pleasant and not so pleasant suprises.
For a more detailed insight and photos of the work carried out, please click on the buttons overhead for details concerning block, heads, fuel, exhaust and gearbox.
