How to test hydraulic roller valve lifters

valves

#1

I rebuilding a '93 s10 Blazer 4.3l “W” motor with 151,000 miles. I have the crank & pistons back in but the lifters are puzzling me. 3 of the lifters I can easily hold in my hand and pump them using a push rod. The other 9 are I can’t move. I have been told and/or read 3 are bad, 9 are bad, they are all ok just put them bad in, etc. I did read lifters should be able to be placed in oil an pumped up to be rock hard and they should hold for 15-60 seconds. If the lifters bleed down (get soft) before 15 seconds or take longer than 60 seconds to bleed down (get soft), the lifters should be replaced. Who is right? There lifters are over $12 a piece, I don’t want to spend another $150+ on lifter to I don’t have too.


#2

Spend the money. You don’t want to keep taking it apart. If the three are bad; how bad are the others? If you know that some are bad, you have to change them all at 150,000 miles.


#3

JMHO, but the lifters should hold up a lot longer than 60 seconds.
Also, when one is rebuilding an engine one should replace the camshaft and all of the lifters. It’s possible to reuse them on a roller lifter engine but it’s not recommended. On a flat tappet engine it’s always replaced.

If one reuses this stuff then you should make absolutely certain the items are in perfect shape. This means checking the cam lobe ramps along with inspection of the cam lobes and lifter rollers for pitting. This may even require a magnifying glass because what may appear with the naked eye to be a nice finish may actually resemble the surface of the moon.

From a DIYer standpoint you can try to reuse them; for a shop doing a rebuild there is no way they would reuse a 155k miles camshaft and lifter set; especially if the lifters are not marked and going back into the same hole with the same orientation.
The point being that the hard coating may be getting thin or beaten through and once this happens the life of the part is shortened quite a bit. One would hate to assemble an engine and have the cam go flat or a lifter(s) disentegrate on you.


#4

Hydraulic lifters are pumped up prior to installation by putting the lifter in a CLEAN coffee can with several inches of CLEAN oil in it. Using a drill press or similar fixture, put an old pushrod in the chuck of the press and pump the lifter a few times. It should fill fairly quickly and should not leak. Once filled it should be pretty solid.

With flat bottomed hydraulic lifters this is a pretty simple process, but since you’re using roller lifters you’ll need to come up with a fixture to support the lifter as you use the press on it.