Mattman, your original post states: "...After having the head milled/planed during the rebuild will the shims need to be altered when I install new hydraulic compensators?". Next we hear that "...The motor was never overheated so the heads weren't milled...". (Italics mine). I think we'd all like clarification on whether the heads were milled or not before proceeding. What exactly was 'rebuilt' during the rebuild?

As to your other question, re. doing all or just the offending lifter/HLC replacement, I'm voting for locating the bad one(s) and replacing them only. Get a mechanic's stethescope and listen to all 8 (on your passenger side, as you posted) through the valve cover while the engine is running to aproximate the cylinder/valve that is ticking. Then pull the valve cover and remove the rocker arm on the suspect valve.

The procedure, as I recall, is to push down on the lifter with something like a wood hammer handle and check the resistance compared to a known 'good' lifter filled with oil. A bad one will collapse easily when you push down on it.

I also think your dealer is full of it...if they replace all of the lifters, you're going to need all new rockers too, and each one is going to require a shim check with the guage as described by the other posters. Big $$, both labour and parts.

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1986 560SL
2002 Toyota Camry
1993 Lexus