1984 xjs v12, 5.3, he. since I don't know the history of this car-speedo shows 80k miles-? I don't now if the valves have been adjusted. Should the valves make a small 'clicking' noise like a sewing machine--or be 'quiet'. This V12 has NO valve clicking at all, wondering if the valves are too tight. Large job to just check the valve clearances. Car runs good & smooth.

 

The valve clearances will be fine. Drive the car and forget them. They are such that, unless there has been a materials failure, they cannot really change significantly. The tappets are not noisy on a V12.

To measure the clearances involves removing the induction, then the cam covers and then measuring. To adjust them involves removing the camshafts and the timing chain and lots of other grief - all completely unnecessary Believe me, they are fine!

Greg

 

As Greg said, worry not.

Come back in about 200k miles time and they will be the same.

The V12 should be almost silent, even by todays engine standards.

One warning, you may or may not this one.

NEVER EVER overheat that engine. If you do, the concern about valve clearances will be the least of your worries.

SOOOOOO, the cooling system cleanliness, INSIDE and OUTSIDE is paramount.

None of mine run hot, V12 or the pretend engined ones, never have, and we have 46c+ summers to deal with.