Hydraulic Lifter Plunger

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72Dinger

72Dinger

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I have stock (presumably) lifters in a good 318 engine (that had been rebuilt professionally probably 10 years ago) that I'm simply cleaning up to drop back in place. I thought I might had some trash in one so I'm going through them one at a time.

I remove the the spring clip to remove the plunger cap. With it comes out a small metal disc that sits inside the plunger and against the plunger cap. It doesn't appear on the '70 factory service illustration. The disc is not perfectly flat, it has some concentric indentations. Has anyone seen this? If so can you tell me if the orientation of the disc matters for reassembly?

lifter.png
 
It is a metering disc to meter oil through the pushrods to oil the top end.
 
Thats kind of what I figured. I'll try to pop one of them apart and take a pic of the disc. Problem I'm having is that it sort of falls apart before I can take note of its orientation.
 
The reason the factory lifters didn’t have it is because the factory wasn’t worried about metering oil to the pushrods.

Some of the aftermarket lifters are also used for AMC applications...... which do pushrod oil the top end.

I don’t think the orientation of the disc matters...... but some careful examination should answer that question.
It’s purpose is basically to create a controlled leak path for the oil to the pushrod cup.
 
IIRC all the aftermarket "Mopar' lifters are in fact AMC/Magnum spec 'oil through' now. It just makes sense to make 1 lifter for 3 platforms nowadays. Make sure there is no 'glitter' in the bottoms of the lifter, that's where all the trash ends up (can't go anywhere) and can cause check valve issues. Fun fact: the early B motors had a smaller pushrod tip radius than the later ones so the lifter part numbers may be different!
 
Just a follow up on this - went through the remaining lifters and found most of the metering discs oriented one way, but a couple oriented the opposite. So seems to confirm it doesn't matter at all regardless of application. I will be leaving them inside the lifters.
 
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