Just in process of checking shim and valve clearances, and wouldnt mind a bit of guidance as to whether to replace shims or not.... as have said in other threads, this is resulting from tapping noise in engine (RHbank) as engine warms up, and is worse under acceleration but drops off when engine drops down, until idling when comes back again.... have done timing chains, and noise is still there so now checking the clearances before going further...
Inlets all seem fine (ranging between 0.19 and 0.21mm / .0075 and .0082"), but exhaust seems to be a tad below JTIS specs (cyl 6: 0.3mm (.012") & 0.34mm (.013") ; cyl 4: 0.36mm (0.014") & 0.38mm (0.015"); cyl 2: 0.3mm (.012") & 0.3mm (0.12") ). The first one on Cyl 6 and both on Cyl 2 are 0.33 - .38mm (.013 - 0.15").
Is it worth replacing these at this time, and could this minor difference pos be the root of all evil in my life at the mo? I appreciate that this is difficult to assess online over a forum but any assistance would be great! I also appreciate that the exhaust valves and shims will expand more due to less cooling air, and also that the RH bank is more liable to heat than the LH, due to position of the horizontal Cat lying just behind.....
Oh and BTW, if anyone wants cheering up, I'm doing this on my drive at the mo, and its just started snowing.....[sm=headbang.gif][sm=imsmilin.gif] lol cheers in advance to anyone!!!

 

are you sure the exhaust and in let clearances are the smae spec.. i just did this on a V8 and they were different for inlet and exhaust

 

sorry Jag-genius, I should have said - yes, the intake and exhausts are different spec, with the intake being between .007" & .009" (0.178 - 0.228mm) according to JTIS, and the ones on the car fall between these ranges as per original message, so these are ok (surprisingly - thought it was going to be the intake ones which were going to be out!) - if the exhaust ones are considered to be acceptably below (although prob needing changing at some point), it means more investigation, taking cams out, checking valves, valve springs, and then going further down....something I'm not particualrly relishing (but then the bill at the garage I relish less!!! lol) - thanks for the question tho! Appreciated, Si

 

I've only re-shimmed 1 V6 and it was only one hole and it was much farther out than the numbers you have measured. It was also a low mileage S-type that I feel was mixed up at the factory. This was 4 or 5 years ago and I can't remember exact numbers but .020 inch out of spec sticks in my mind.