Tappet adjusting pad

Jaguar: XK8 (X100) 4.0 and 4.2 to VIN...A48684 (1996-2005) • XK8 (X150) 3.5 and 4.2 from VIN...B00379 to B32752 (2006-08) • X308 (XJ8) 3.2 and 4.0 from VIN...812317 to F59525 (1997-2003) • S-Type 4.0 and 4.2 V8 from VIN...L00003 to N91220 (1999-2007) plus 3.0 V6 Petrol from VIN...L00003 to N91220 (1999-2007) and 2.5 V6 Petrol from VIN...M45255 to N91220 (2002-07) • X350 (XJ) 3.5 and 4.2 V8 from VIN...G00442 to H32732 (2003-09) • XF (X250) 4.2 V8 from VIN...R00001 to R47153 (2007-09) • X-Type 2.5 V6 and 3.0 V6 Petrol from VIN...C00001 to J63579 (2000-09)

thickness 2,51 mm <> 0,0988 inch --- (diameter 30,0 mm <> 1,181 inch) Original number AJ84908

Top-mounted camshafts in combination with cup tappets have a number of design advantages. The direct drive of the valves has a low profile and allows maximum performance with few moving parts. Tappets with a shim for valve lash adjustment provide a firm connection for actuating the valves. The design is very reliable even under thermal load, very speed-resistant, cannot move and the maintenance intervals are long. The alternative to bucket tappets with shims are bucket tappets with hydraulic valve lash adjustment, in short: hydraulic tappets, which, however, can wear out and are far less solid and therefore less reliable in operation.
Adjusting the valve lash using shims therefore has a number of design advantages that are used in many demanding engines. These include: Many high-revving motorcycle engines, some Alfa and Fiat machines or even the current Jaguar AJ8 engine
When it comes to adjusting the valve clearance, you need a micrometer screw, a calculator, a variety of shims in the back, a feeler gauge and a lot of patience. That's why valve clearance adjustments with shims are considered difficult, but this is not true: With a system and the right tools, valve lash adjustment is quite feasible:
If you do not want to leave the engine open, make sure you have a sufficient supply of shims in advance. Used shims without traces of use can be reused, please check the printed dimension with the help of the micrometer screw. Many shims are labeled in inches and metric. Usually it is much easier to calculate with the metric dimensions. Errors in the conversion range occur, please check the plausibility of the selected shims before assembling.