Postby smj999smj » Tue Jan 29, 2019 10:15 pm
They are solid, bucket tappets. Unlike earlier VQ engines, they do not have replaceable shims, so the proper sized bucket tappet has to be determined by checking each one's valve clearance and figuring out what size tapped will be needed to get the clearance in spec. It is a very time consuming job and does require removal of the camshafts, which in turn requires removing the front cover assembly and timing chains. I won't say they never fall out of adjustment, but it's not uncommon. If you here a lot of noise, you may want to make sure the oil pressure is not too low, which can occur if the gallery plate gasket blows out on the rear timing cover. Another thing that can sound like a lifter tap is an exhaust leak at or near the exhaust manifold. There have been cases of cracks developing near the flanges on the VQ40DE manifolds.