[DeTomaso] rocker arm adjustment

JDeRyke at aol.com JDeRyke at aol.com
Mon Jun 14 15:20:56 EDT 2010


Justin, are you sure the assembly was done properly? By that I mean, the 
rocker pivot shaft inside each of your rocker arms have a flat spot for the 
adjusting nut to bear on. If the rocker was installed with the centeral pivot 
180 degrees out, you'll be trying to tighten a flat nut against a 
cylinderical surface. Forgive me but I've seen even experienced for-pay engine 
builders do this, and it always ends in curses and a tear-down. Where nothing is 
found to be wrong so a reassembly with the same paets- done correctly- 
mysteriously works fine.

Second point: valves wear-in against their seats, lifters wear-in on their 
cam lobes, bubbles in the oil inside hydraulic lifters very slowly bleed out 
which changes the adjustment, and even (apparently) metal stretch on the 
studs, nuts and setscrews all tend to change a 'final' rocker arm adjustment. 
It took me three tries over a 2-month period to get mine hot-adjusted 
properly. Since then, they've held for 19 years! FWIW, I use Rhodes hydraulic flat 
tappets, Sharp full-roller rockers and a Ridgeway stud girdle on our 
engine. Good luck- you'll get it eventually- J DeRyke



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