How do i eliminate lifter tick?

68 MGB said:

I have a lifter tick in my engine of a type that has been described in earlier threads. Basically, the engine is quiet when cold, and develops the tick when warm. The noise is most noticeable between 2000 and 2500 rpm. I am running 10-30 Castrol, and fixed the problem by replacing one quart of oil with Lucas oil additive (in the earlier thread Slick 50 accomplished the same thing). I do not like this fix because i started with a new GT40 (aluminum head) crate motor and it did this from day 1. Later I replaced the B303 cam with a Comp Cams XE264 HR (.512 lift). Lifter preload was fine. The noise got worse over the next 5,000 milers so I put in a set of Comp Cams lifters. The noise decreased but did not go away. The only thing that fixed it was the Lucas oil additive. Considering the engine is supposed to run on 10-30 and is essentially brand new, this is wrong. Oil pressure at 800 rpm idle was 40 psi hot, now it is 50 psi hot. I know it is not an exhaust leak (I built my own headers and tracked down and welded up all the pinholes) or rocker problem because I have the pedestal rockers that are not prone to this problem. I almost think the lifter bores are machined oversized ...

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