Am I supposed to be able to do this?!?!
10-23-2012, 07:56 PM
#1
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Am I supposed to be able to do this?!?! Chasing down a lifter tick...from a previous thread I posted regarding preload:
"I recently developed a lifter tick in what seems to be my #1 cylinder. JY 5.3 longblock, with xer273hr-14 cam, PRC dual springs and new LS7 lifters.
Cam specs: 224/230@114 .581/.588, XE-R lobes
Initially I was running comp magnum 7.425" pushrods. Car ran great, valvetrain was quiet, no problems. Began a few idle tuning sessions, logging airflow and letting the engine heat up to 220 degrees or so. On roughly the third session, one of the lifters for the number one cylinder (i suspect) began to tick. It will stay quiet regardless of temperature until I blip the throttle, then it begins to clatter away. The tick will not go away regardless of rpm or temp when it begins. I used a large screwdriver to pinpoint the location of the tick. I can also hear it out the exhaust, which makes me suspect it is the exhaust valve lifter. This is not a faint tick, it is very loud and noticable."
So I pulled it apart to check things out. Keep in mind the lifters have been sprayed out with seafoam in an attempt to clear any debris, so obviously they arent pumped up. Even so, I dont think I should be able to do this.
http://youtu.be/gEsaL4F4WGE
Is this an obvious collapsed lifter?
"I recently developed a lifter tick in what seems to be my #1 cylinder. JY 5.3 longblock, with xer273hr-14 cam, PRC dual springs and new LS7 lifters.
Cam specs: 224/230@114 .581/.588, XE-R lobes
Initially I was running comp magnum 7.425" pushrods. Car ran great, valvetrain was quiet, no problems. Began a few idle tuning sessions, logging airflow and letting the engine heat up to 220 degrees or so. On roughly the third session, one of the lifters for the number one cylinder (i suspect) began to tick. It will stay quiet regardless of temperature until I blip the throttle, then it begins to clatter away. The tick will not go away regardless of rpm or temp when it begins. I used a large screwdriver to pinpoint the location of the tick. I can also hear it out the exhaust, which makes me suspect it is the exhaust valve lifter. This is not a faint tick, it is very loud and noticable."
So I pulled it apart to check things out. Keep in mind the lifters have been sprayed out with seafoam in an attempt to clear any debris, so obviously they arent pumped up. Even so, I dont think I should be able to do this.
http://youtu.be/gEsaL4F4WGE
Is this an obvious collapsed lifter?
10-23-2012, 09:08 PM
#3
If it's pushing back I can't see how it's collapsed. If the roller **** the bed it may still push back, but there would most likely be daylight between the pushrod and rocker seat when on the base circle.
How does it feel compared to the others?. That lifter may have a much higher leakdown rate than the others which would make it loose pump more quickly...but after the oil is out they should all feel about the same.
How does it feel compared to the others?. That lifter may have a much higher leakdown rate than the others which would make it loose pump more quickly...but after the oil is out they should all feel about the same.
10-24-2012, 07:07 AM
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Yeah, I was a little suspicious of it. The exhaust valve on #1 was cleaned/sprayed as well and has a little play, but nothing like that one. Im assuming that its bleeding off and cant pump up quick enough. It will be quiet until I blip the throttle, then it will tap away as if it cant pump back up. I rechecked my preload and picked up the proper size pushrods this time. If I reinstall them and it still taps, its time to pull the head....
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10-24-2012, 01:03 PM
#8
On a completely bled down lifter you will be able to push in the lifter cup due to the fact that the spring is the only thing holding the lifter cup up. with that being said the ls7 lifters only have so much travel on that spring and from your video it looks like your travel exceeds those that i have seen. Also its hard to tell from the video but it should take some force to push in the cup, not a ton of force but some force.
10-24-2012, 01:13 PM
#9
^^^yup, completely bled down stock lifters are pretty soft.
It is hard to tell on the range though, remember the rocker multiplies the travel...but you can indicate the prod side and see if you get 200 minus your preload.
My bet is that lifter has failed as ad check valve but is not yet collapsed/seized.
It is hard to tell on the range though, remember the rocker multiplies the travel...but you can indicate the prod side and see if you get 200 minus your preload.
My bet is that lifter has failed as ad check valve but is not yet collapsed/seized.
10-25-2012, 07:13 AM
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Welp, will have to hold on on updating this thread. Thanks for all of your input on this, but it appears that I have bigger problems. Fired it up last night with the new pushrods and had 0 oil pressure. Im going to replace the pump and pickup and take it from there. Ive been a bit concerned about the pressure lately anyway. First start up it was roughly 40psi and had worked its way down to 20ish last time. If i have oiling problems, I would rather experiment on the current lifters than a new set. I will let you know how it turns out.
10-25-2012, 10:41 AM
#11
Did you just do the cam?? Could it be possible you pinched the o ring on the oil pickup? That looks pretty weird and now your not getting and oil pressure hopefully it didn't hurt anything else !
10-25-2012, 12:24 PM
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Anythings possible. I installed the cam with the motor on the stand. Ive done some reading on the o-ring. The installation of it is definitely much more important and takes much more attention than I probably gave it during the install. You live and you learn.
10-25-2012, 12:27 PM
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The pressure never fluctuated, just lessened everytime the engine was started. First fire was roughly 40 psi, then 35, 30, 25, 20, now 0. No noises other than the lifter tick, which I'm assuming was due to the lack of oil pressure.