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We do "off the vehicle" bench testing and ultrasonic cleaning of fuel injectors, for all makes and models of Jaguar vehicles.  We can also do the same, for multiple other vehicles....including Porsche, BMW, Ford, Ford Mustang, Chevrolet, Pontiac, Toyota, Audi, Buick, and multiple other engines.


Fuel injectors that are not balanced in fuel delivery flow, can cause a number of engine performance problems...loss of HP, poor fuel economy, hard starting, overheating, and burnt exhaust valves.


In early May, 2008, I was contacted regarding a set of V12 5.3 liter heads I have for sale.  The individual wanted to know specifically, whether my 5.3 HE heads, would fit a 1995 V12 engine, with a 6.0 liter engine.  His 6.0 liter engine heads has several burnt exhaust valves, and needed rebuilding, or replacing.


I suggested he contact Roger Bywater, at AJ6 Engineering, for professional advise.  He did so, and he also sent Roger a photo of the burnt exhaust valves.


The photo is shown below....





Clearly visible on the two exhaust valves at the left of the photo, they are severly burnt thru on the seat.  The exhaust valve on the far right, is ok.  An engine that overheats, due to a cooling system problem, does not cause this type of isolated problem, and will usually result in a dropped valve seat(s).  You can also see the mating seat of the valves are not carboned, so carbon buidup is not the likely cause.  


Roger Bywater was kind, as always, to provide his opinion on the "most likely" cause for the burnt exhaust insufficient fuel supply to these two cylinders , and almost certain to be compromized (weak) injector fuel delivery,  when the engine is at full throttle opening, high load, when the engine goes "open loop".  


"Open Loop" and "Closed Loop"  engine operation, ECU response to O2 sensor input, and injector flow rates in both operating modes,  is more fully explained on our site at  THIS LINK


This damage can occur to any engine.  It's not specific to the V12 Jaguar.


This would not have occured, if the injectors had been flow tested, and the injector delivery flow confirmed, by testing and ultrasonic cleaning.  Cheap insurance to prevent a costly rebuild.


FYI.....The HE heads will fit the 6.0 liter block, but it involves much more additional work, than just to bolt them on.



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