aargee

This is a push rod based engine animation

And this one is for spring valve

My understanding goes that...
Push rods were older technology, makes lots of sounds, too much mechanical movement & parts involved, lot more maintenance required, probably not efficient as spring valves & probably the ones that yielded to the spring valve technology.

Why do some engines still use push-rod technology if they aren't effecient? What is it that makes push rods more special?

Pls help me break the myths. Tks.

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haxor

I guess thats because the push rods are conneted to camshaft which moves the rods and hence the valves operate,how cam you operate the spring operated valve system? And moreover there are springs in the valve tappet settings,so basically they are equal.

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aargee

WHAAAAT???

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RanjithMN

Who needs these vids after a first hand session with you?

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aargee

Ranjith...trust me, I'm still learning!!! And I'm thought someone will help me with the flow. Its been lying here for quite sometime unanswered!!!

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Patience pays...The Vulture's virtue is patience and the bird always get it's food - Wise man saying

This is not a bakery. I don't sugar coat anything. If you ask for my opinion...then that's what you'll get. Don't be mad when it's not what you want to hear

tanay

Well one thing I remember is that due to the mass of the long pushrods, high rpm operation is difficult. This problem was solved somewhat with the spring valves.

Harley uses pushrods in its engines, maybe the VRod is an exception. I think they use pushrods because their engines remain unchanged from years ago.

The wikipedia page has some advantages:
Overhead valve - Wikipedia, the free encyclopedia

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vikram kumar

I guess the main advantage will probably be that you can control the valves in a V configurated engine with a single cam.

The spring valve means that each cylinder head would need its own cam.
If you had a V engine then you would need 2 cams.
One in each cylinder head.
But a single cam in the center with pushrods can control all the valves.

aargee

That is my point!!! If spring valves are effecient, then why do HD & RE (these are what I can recall now) still use the old push rod technology?

Not necessarily a V config; Old Triumph's had parallel twin & uses push rods.

The old Honda CB650 had a inline 4 with SOHC. Which means multiple cylinders & DOHC are independent.

Hope you meant a single CAMSHAFT mounted with multiple CAMS.

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Patience pays...The Vulture's virtue is patience and the bird always get it's food - Wise man saying

This is not a bakery. I don't sugar coat anything. If you ask for my opinion...then that's what you'll get. Don't be mad when it's not what you want to hear

antz.bin

I was about to post "They dont change it because it was being used since ages and they were too lazy for a redesign"

But then I decided to give it a thought... and found this:

2009 Yamaha MT-01

2009 Yamaha MT-01 Features:

Engine:

High-performance, 1670cc air-cooled, long-stroke, OHV, 4 valves per cylinder, 48°, V-twin powerplant produces massive torque and strong acceleration for an emotionally charged ride.

Traditional pushrod valve actuation keeps engine height down for a lower centre of gravity for great handling and ensures more uniform heat dissipation due to absence of a cam chain case.

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