Bad lifter or what??

[RECHRGD]

I reset my timing today after goofing around with the distributor a couple of days ago.  Got it all dialed in and went for a cruise.  I found a back road where I could practice launching from a stop.  I brought it up to about 3000rpm, then lifted the brake and nailed it after it had moved a few feet.  It launched nice and hard and I got out of it after the 1-2 shift.  After about a 1/2 mile of just cruising at about 45mph,  I get like a loud lifter noise coming from the engine.  It kind of sounded like a lifter that wasn't "pumped up" on an initial start up or something.  After about 5-10 seconds it quieted down and the engine sounded normal again and drove fine.  What happened?  Oil pressure was good.  The lifters are Comp Pro-Mags and went in with a new cam and head swap out a couple of winters ago.  There's only about 3500 miles on the engine since the install.  I'm using Crane Gold roller rockers with the Mopar 452 Aluminum heads.  The cam is a Comp hydraulic extreme energy high lift piece with 526 lift.  Is there somethere happening in there that I should be worried about?

[firefighter3931]

Bob, it sounds like the lifter bled down....then pumped back up. Hyd lifters will bleed down at higher RPM....especially with agressive fast rate of lift cam profiles. I would try to limit rpm to 5800 to keep this from happening again. 



Ron

[RECHRGD]

Bob, it sounds like the lifter bled down....then pumped back up. Hyd lifters will bleed down at higher RPM....especially with agressive fast rate of lift cam profiles. I would try to limit rpm to 5800 to keep this from happening again. 



Ron

Thanks Ron!  That's exactly what it sounded like.  I've got it shifting at around 5800 now.  It just seems odd that a month or so ago, I ran it through the 1/4 mile several times and never experienced this.  On a couple of those runs I was even shifting at around 6100.   Bob

[firefighter3931]

Bob, it sounds like the lifter bled down....then pumped back up. Hyd lifters will bleed down at higher RPM....especially with agressive fast rate of lift cam profiles. I would try to limit rpm to 5800 to keep this from happening again. 



Ron

Thanks Ron!  That's exactly what it sounded like.  I've got it shifting at around 5800 now.  It just seems odd that a month or so ago, I ran it through the 1/4 mile several times and never experienced this.  On a couple of those runs I was even shifting at around 6100.   Bob

Bob,

Hyd lifters can be finicky at times.....that's just the nature of the beast, unfortunately. Keep an eye on it and if the issue crops up again you might need to replace a lifter. Hopefully this was just an isolated occurance.


Ron

[RECHRGD]

Thanks Ron!     I drove it over 100 miles to a show and back yesterday without any issues.   Bob