YL Al

simple question, based on 24 valve sohc engines(like the j series)

how do you fit 4 VALVES on one camshaft?

dont the valves make a square,2 intake next to eachother and the 2 exhaust in the back of them? so how do the lobes on the camshaft connect to the ones in the back?

Cocoa

iTrader: (2)

24 valve

12 intake, 12 exhaust

2 intake, 2 exhaust per cylinder.

Camshaft hits rocker arms, rocker arms extend valves.

Each rocker arm pushes down on 2 valves of the same type (intake or exhaust).

Applicable for OHC engines.

With OHV you have the camshaft hit a pushrod, which hits a rocker arm, which hits the valves.

Help any?

YL Al

awesome u da fawkin man! so basically on the j30a1 the cams hit two rocker arms which goes to the two front intake valves and the other arm goes to the two back exhaust valves?

SupraManAG

J series is a V6. Meaning you have two halves of 3. Its the same setup as the inline 4 with 4 valve per cylinder. Instead of two cams you guys have 1 with a lot more lobes i guess.

SupraManAG

Any camshaft hits rocker arms which then hit the valves. If you ever take it apart its pretty simple process. The timing everything works in synch is real neat.

YL Al

well accually as i remembered now ,if u have a dohc engine,the cams on the camshaft sit directly on the valve stems, so no rocker arms are needed on a dohc. but like cocoa said if u have a sohc u need rocker arms as its not possible to have four lobes sitting on one cylinder with 4 valves.

Cocoa

iTrader: (2)

Looking at this diagram, I guess we have 1 rocker arm per valve. My bad. I thought it'd have that plate underneath the rocker arm that pushes down on 2.

Cocoa

iTrader: (2)

Looking at this, it shows me that with one cam shaft, you get:

1 lobe for 1 exhaust valve, 1 lobe for 2 intake valves, and 1 lobe for an exhaust valve, then the same pattern continues for the next 2 cylinders. Assuming this head is the front head in the picture.

YL Al

ok ok so wait we have three rocker arms? or one rocker arm and 2 direct lobes?..what about vtaaaakkk in that case

but dude that j35 is siiicckkkkkkkkkkk is there a thread about that swap?

Cocoa

iTrader: (2)

A rocker arm for every valve.

As for vtec, you have your primary and secondary lobes for the intake valves. One being for vtec, and the other for the rpms underneath that.

SupraManAG

DOHC have rocker arms. H22 do not have rollers on them but F22 does.

Cocoa

iTrader: (2)

^ Isn't that weird. Because roller rocker arms are usually used for "high performance" engines.

Jim Truett

Unless the added mass of the roller bearing becomes a liability to reaching the design's maximum intended operating RPM.

Roller rockers are also used to decrease friction to aid in increasing fuel economy.