Hydraulic Lifters (problem with different lifters smae part number)

Hello everyone,
I discovered while rebuilding my SBC 350 upon priming the hyd. lifters that some are a little different but same part number.

The difference is being able to push down on the plunger with the pushrod. Some are very very easy to push down and some are not at all easy to push down. I have noticed a slight difference in the machining of the lifter as well. Some have some sort of machined groove around the lifter base about 3/16 inch up and others are smooth. This ridge or groove is machined into the lifter as I have 12 of them this way and 4 that are smooth. (not sure if this is a good description).

The main thing is the ease of pushing the plunger down on some and others hardly move.

Has anyone encountered this before or know what this is?

Any and all help is greatly appreciated as this puts a hold on the buildup I am doing. If all else fails I can drive to Summit Racing, but would like to avoid this if I can.

Thanks,
Aaron

i would hafta say the diffrence your feeling in the plunger is due to hte amount of oil in the lifter. as for the band you see, thats just differnt vendors. what brand of lifter are they?
also be sure to use rotella 15-40 when you break in the new cam and if you are using doul springs remove the inner upon break in or you risk rolling a lobe during brake in due to having too much spring pressure.

True, I understand if they did have oil pumped up in them. Problem is these are straight out of the box.

What I have found out is standard OEM are like we have all seen, you can push the plunger down a little bit, especially when setting them up at install, (1/2 turn past zero lash). Some of them (same part #) have a retainer ring that limits the plunger. I have found a few sites that talk of these and name them as Hi-Rev lifters. You do not have to put pre-load on them when installing. Just zero lash and run them.

Thanks for you reply.

PS these are Sealed Power HT-817. I belive Sealed Power has a production error of what gets put into the boxes, the zero lash hydraulic lifters should be part # HT-817R.

if those lifters are anything like COMP R lifters that means they are a tru race lifter and are to be adj 2-4 thou and need reg attn.
when lifters come from hte factory they have a protective oil in them and im gonna say that is what your feeling.

The lifters with the little groove about 3/16 above the base are referred to as hard-faced lifters and are much better material on the face where it runs on the cam. Less chance of getting a flat lobe. Also like mentioned above run Rotella when breaking it in.

i didnt pay attn to the part about the description of the base of the lifter, those are delphi lifters and are actually a lifter GM has been using for years.......well untill they went full roller. those delphi lifters are hard bottomed SOBs. if not broke in right they will eat a cam with a quickness.
also about that 15-40 rotella, you can run it as your reg eng oil without issues.