I'm running dart big M with Crowder tall hyd roller lifter (Gen Vi type) as recommended by dart and after one to two weeks without running engine some of the lifters leak down (guess it depends upon which lifter is left under valve spring tension when the engine stops), when starting after this one to two week period, lots of valve train noise until oil pressure builds and pumps up the lifters. Always start with "quiet" exhaust and you can really hear the valve train. Soon as oil pressure builds it goes away (5 to 10 seconds). I installed a pre-luber pump to raise oil pressure to 40 psi, let it run for a minute, bump the starter to open closed valves and close open valves then run for another minute, starts very quietly then. Am I the ONLY person that hears this or are all my VERY EXPENSIVE lifters all bad?

What kind of spring pressures are you running above these hydraulic lifters, ie; closed and open pressure at their current installed height? How did you adjust the lifter preload on the original setup? A little bleed down is going to happen on any hydraulic lifter under spring pressure, but yours sound a little more than normal. What happens when you restart the motors "quiet after 15 or 20 minutes? What weight oil and type are you using?

Regards,
Ray @ Raylar

Sounds like your srpings are to heavy, or you have the rockers to tight.

I am going to have to go with Ray on this.

surely you are not using the GM lifter!