Brent,
One of my customers told me of your plight on the forum here and suggested I pop in. I am sorry to hear of all your troubles. I am 90% sure I know what is happening to your adjustment, although the answer may not be well received.
First, the push rod cups are wearing away due to lack of lubrication. The
oil feed hole from the rocker is not enough for this design, it requires small block/460 lifters with
oil feed holes and push rods with the corresponding
oil feed holes to supply proper oil to these rockers. As the cups wear, the lash opens, -you have already seen this, but have been hesitant to admit it to yourself.
Also, check the roller tips on the rockers. Roll them around with your finger and see if they roll true and do not have any out-of-round or up and down type movement. There is a good chance they will have this movement.
Next, pull a rocker assembly apart and "feel" one rocker on the shaft. Try and move it up and down and then forward and back. Does it feel like there is a bit more clearance in the verticle direction? Not scientific I know, but I doubt you have a small bore guage to check bore id.
What I am leading up to are the typical failure areas we have seen with the POP rockers. They offer both ball and cup and ball and ball rockers, both styles have failed-wearing quickly away at the push rod contact point. The bronze bushings wear at the bottom of the rocker where the rocker arm presses up against the shaft-ie. they wear out of round. Lastly, the roller tip quickly wears into an oval shape on the inside, allowing the roller to act like an eccentric, tight against the valve tip one time and loose the next. (This really shows up when setting lash, as the now eccentric tip "grabs" the feeler guage as you try to remove it.) We have experienced this type of wear in less than 20 pulls on the dyno, so that would correspond with your short driving trips.
Now, it is IMPORTANT TO NOTE: we experienced these and other problems with the Precision Oil Pumps Rockers during the summer of 2002. We have not tried any additional POP rocker components since last year, prefering to stay with tried & true designs we are more familiar with. -----SO THIS INFORMATION IS A YEAR OLD.------Doug may have implimented changes in design and manufacturing since that time. But, I continue to hear stories like yours.
PLEASE, FOR THOSE READING THIS, IF YOU HAVE POP ROCKERS, DO NOT ASSUME YOU HAVE A PROBLEM. CHECK AND MONITOR THE ROCKERS PERFORMANCE. DO NOT CALL POP AND TELL THEM SUCH & SUCH SAID THIS OR THAT. If they have improved the product, it would not be fair to call Doug without due cause.
Good luck with your engine, we can all empathise with you in your frustrations.
Rob
Hybrid Mode
