Hydraulic Lifters for Mechanical Dummies

Hydraulic Lifter Diagram

It should come as no surprise that we run across a surprising number of eHow.com posts written by people who'd never even heard of the question before they "answered" it. We don't know about you, but we rather doubt that someone with exactly the same amount of knowledge about a topic – if that much – can give us the answer we want when we're doing research. Here's an example: freelancer Regina Paul attempting to explain, "How Do Hydraulic Valve Lifters Work?"¹ for Hunker.com.

Why it's at Hunker, we have no idea, but that's on Leaf Group. Paul's the one responsible for telling us that

"All engines have hydraulic valve lifters in one form or another."

Which would come as quite a surprise to anyone who's ever tuned up an air-cooled Volkswagen engine! But wait, Regina has more amusing information:

"They were created to get rid of the need for combustion engines to have mechanical clearance in the engine's valve train."

We guess that's a bastardization of what Regina found in Wikipedia, which says, "[S]olid valve lifters require regular adjusting to maintain a small clearance between the valve and its rocker." Wait 'til you see what Paul says about why solid valve lifters and why we have them:

"The reason that clearance is required is to keep the valve from being held open and thus destroyed as the valve train goes through its process of thermal expansion."

Huh? Oh, yeah, it's Wikipedia again: the clearance "prevents the parts from binding as they expand with the engine's heat"; so we guess that's what she means by "its process of thermal expansion."

Next, Regina meanders over to tell her readers that when your lifters aren't working, "you may hear a knocking noise when you start the engine." We think it's less of "knocking" than "ticking," but what do we know? We've actually seen a valve lifter. Whatever, Regina then powered into how lifters "actually work" (some CE needs a hand-slap!).

All we have to say about her description is, "Wow: 316 words and we can't make heads or tails out of it!" Well, that's not really fair. After we've read the description of lifters at Wikipedia and combined it with a pre-existing knowledge of A) the hydraulic principle and B) how a push-rod pump works, we sort of figured it out. Still, we rather imagine that in the process of transcribing someone's description (this one), Paul was probably confused at least once, if not more. Even if she wasn't, trying to read her stream-of-consciousness version is all we needed to name her Dumbass of the Day.

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/how-does_5006538_hydraulic-valve-lifters-work.html

copyright © 2018-2022 scmrak

SE - ENGINES