Guys, please help. Need theory. looked through this forum and found out that after assembly of heads/valvetrain initial preload of lifters should be done (+1.5 turns in after "zero"-lash). OK, no problem. The question is how adjusting screws are locked in position in rocker arm. On other engines with adjustable lash there's usualy a counter-nut on the bolt, that is also tightened and it holds the bolt in position. But in this 2.9 mother it's just a bolt in the arm. What prevents it from unscrewing? Just can't get it.
Pardon my English, I'm from Russia, but hope that I explained what I want to know )
Thanks!

 

Some of the 2.9 engines had adjustable rockers, some did not. It sounds as if yours is one of the ones that does not. In this case, there is no adjustemet and the rockers are pre-set with what is presumed to be close enough to the correct lifter preload.

And your English is excellent, I have no problem understanding what you are saying!

 

i thought if it has a screw then it has to be adjustible

PS thanks for my English

 

Yes, you do have the adjustable rockers. You can turn them with a wrench, they have no locknuts but are tightly fitted to the rocker which keeps them from coming out of adjustment.

 

Thanks! That's really good news. A good start of у new day

 

All 2.9's have the same rocker arm set up.