Should My Lifters Bottom With Light Thumb Pressure On The Rocker Arm?

Opie390

Member
How stiff should hydraulic lifter's be? should i be able to compress my lifters easily with just thumb pressure on the rocker arms? this is after the lifters have bled down. or is it not an issue since its the oil pressure that maintains zero lash isnt it? ive asked similar question before. it would be cool if somebody could answer the question instead of giving 100 links to sift through.not to be a dick cuz I know it sucks to see the same questions asked cuz people dont make any effort to search the forums. but Ive been readin links for months and dont get me wrong I appreciate the hell out of grumpys for all the info. its a 69 390, with maybe 15-20k mi since added the crower cam, lifters and valve springs etc. so are my lifters shot?
 
its very unlikely your lifters are "SHOT"
its also unlikely you have serious wear, with the limited mileage.
on engines with more miles,
adding a quart of marvel mystery oil with its detergent solvents,
will tend too free up varnish clogged lifters.
why not pull the valve cover and inspect the valve train?
oil pressure under the push rod seat is what maintains the clearance , without constant oil pressure
,the lifter seat can rather easily be depressed,

and it won,t return, to the extended location without oil pressure,
keep in mind oil can,t as easily bled from the lifter body,
if the lifter is inside the block lifter bore,
except in the location with the lifter on the cam lobe base circle.
once its push rod seats depressed (most only move about .080 max)
it won,t reset or expand out, without oil pressure under the seat.
Id also point out that squeezing out the trapped oil in a non-running engines lifter is not difficult.
remember even at idle lets say, 750 rpm,
that lifters push rod seat is being filled and depressed about 6 times a second,
so that drain out time frame ,
and distance the seat moves to drain the trapped oil, is minimal.

http://garage.grumpysperformance.co...ter-pumps-oil-and-traps-oil.15555/#post-92843
 
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since added the crower cam, lifters and valve springs etc.

I personally don't see how a lifter can completely lose all the oil in it on bleed down and be able to push the plunger all the way down.

Why not call Crower? They should be able to answer that since it is there product.
 
got to ask, what is the issue that 390 AMC engine is having that has you taking it apart and considering the hydraulic lifter preload as a potential issue?
Ive only built a few 343 and 401 AMC javelin , AMX and rambler engines but they certainly have decent potential

I always liked the way the AMX looked.. theres an exceptionally clean blue/grey AMX that shows up at local car shows around here at times. that looks vaguely similar too this

1970-amc-amx-go-package

71295amx.jpg
 
  1. its not an AMX, its a 390 in a 69 Mach 1. i developed an engine vibration or miss like a plug wire was off. after checking all wires with timing light for any misfiring, i slid a stethoscope along the valve covers listening for clues and found #2 cylinder rockerarm noise significantly louder. pulled valve cover and found the valvespring shims torn through and pushing out from under the springs. the #2 E and #1 I lifters are stuck compressed while after bleeding down, all the other lifter's springs are easily compressed and expand fully on their own. im going to try Marvel Mystery Oil to hopefully unstick them, if it will work without engine warm i dont know. otherwise ill have to pull the rocker shafts and intake and free them up myself or just replace them all. if anybody has a quality flat tappet hydraulic lifter recomendation please share. or is it critical i replace with same brand n model lifter?
 
not an AMX its a ford FE 390 in a 69 mach 1. ok il try to be clearer. i had a vibration/engine misfire that sounded just like a sparkplug boot had come off. ignition was good on all cylinders. so listening around with an engine stethoscope(like a doctors but with the metal rod instead) i found #2 cylinder rocker/lifters under the valve cover quite a bit louder than the rest of the cylinders. removed valve cover and found the valvespring shims torn and pushed out from under the valvespring. also that lifter was collapsed.image0000001.jpg
 
Have you pulled the lifter apart to see what actually failed inside? What is the shim made from, aluminum or steel?

It must have been the lifter that failed first and then the shim, don't see how a ~0.030 inch shim
could have broke without enough slack in the valve train to beat on the shim and break it.

What do you think?
 
Yea, if he was turning more RPM than the valve train could control, that might have worked
on the shim to make it fail.
 
i apologize, this isnt storytime forum.

since my buddy mixed up 2 llifters I did replACE the whole set and for the record, the old lifters were very weak in comparison to the new identical replacement set from CROWER. the new lifters are not primed with oul yet but with spring pressure alone they are much stiffer and im sure would maintain zero lash in any situation 100% more accurately and consistently than the old set.
 
I bet many of us have similar stories about trips we took
, and problems faced as a result,
when younger in personally built-up our cars
 
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Say 10 hail Marys and don't do it again for a week!! Never lose the St Christopher or leave it behind!
 
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