Join Date: Nov 2000
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Re: adjusting the valves on my 258
They are hydraulic (lifters) and no provision is made for adjustment. If there is excessive clearance causing the ticking, one or more of the parts in the valvetrain have worn and require replacement. (Assuming normal oil pressure is available to make the lifters work).
I'd remove the valve cover and find out which valve is making the noise. You can run the engine this way, but watch out for oil spurting out the tops of the pushrods. A little strip of plastic sheeting will help. I use the woodend end of a hammer against the rocker arm. You will press down and it will dampen out the noise when you find the right one. Can you feel clearance or a collapsed lifter? If not, you can swap the rocker and pushrod from another valve to see if that moves the noise around. If not, use a dial indicator to measure valve lift to see if the lobe on the cam is going flat.
If the cam lobe is alright, or if the lifter is collapsed, it's time to remove the cylinder head and replace the suspect lifter. I had to do that on my engine and it cured the noise. For some reason, after a rebuild, one of the replaced lifters just wasn't doing it's job right. Cured that annoying tick.