On a vtec head, do the bars only spray oil when VTEC solenoid is activated?

 

WHY ARE YOU ASKING THAT QUESTION

 

good question..
but my educated guess is that they're always having oil showering down on the came lobes... whether vtec kicks on or not.

 

..maybe we learn sometimes by asking questions.
Valvetrain lubrication is important because
it gets twice the abuse for every rotation of your crank.


K, I've gave it some thought and heres what i came up with...
First off, the oil comes up from the rocker shaft chambers ..through the ducts in the cam caps/journals, and up into the spray bars.

In order for spray bars to shower oil over the valvetrain, high pressure oil is needed to fill up the rocker shaft chambers. Looking at the head, the only way the rocker shaft chambers could be filled up with high pressure oil is when the VTEC solenoid is activated. There is no other oil ducting to the rocker shaft chambers ..only through the solenoid housing, and oil only gets into the solenoid housing from: a small drain hole for oil in the head, a hole from the deck of a vtec block (the one you would plug up on the head if you were to go frankenstein), OR if you have a frankenstein, you will basically use one of machined holes to get oil from the oil pressure signal outlet (via steel braided line) to the solenoid.

Im impressed!.. every moving part in the valvetrain is lubricated. The rocker shafts supply oil to all rockers, so they can ride on a film of oil. Cross-hatch patterns were still present when I took the rockers apart. And this is a 89' head.

Cheers to Tokyo

 

I am sure the cams are sprayed with oil constantly. The cam caps and braces are all galleyed together atop. The vtec solenoid allows some oil to go through the hollow rocker shafts, but not enough pressure to engage the vtec locker things. I know this for a fact because I had the valve cover off and idled the engine for a few seconds and oil came a-sprayin. There is also a port connected to the oil passageways you can check for pressure and it is directly connected with the cam journals oil feeds.

At first I thought you were talking about the squirters in the block. Those have a valve the pressure has to overcome before spraying, I am not sure what the exact pressure is, though.

 

Humm, thats interesting. The solenoid is on constantly?, then when rpm vtec pt is reached it just puts out more oil?

 

the oil to the caps and spray bars is from the small orifice that is covered by the middle cam cap, and not from the vtec soleniod. think about it. if it was only activated during vtec, the cams would seize on the low speed cam faster than it took for me to type this sentence. if you want proof take off the valve cover and disable the fuel or ignition system and crank the motor over. the spray bars are spraying oil whenever the engine is turning over.

 

Yea wheather VTEC is engaged or not oil is still pumped up to the cam journals under the cam rails!

 

So, they do really spray.. even with the vtec off.

ahh.. its a beautiful thing, but why dont the non-vtec heads have it?

SR20DE's (Sentra SE-R motors) have sprayer tubes that shower oil over the valvetrain, and they dont have any variable timing.

I have a set of non-vtec cams nearing the 140k mile mark, and they're in great shape. I wonder how non-vtec heads supply oil to the valvetrain. I had the non-vtec motor running once ..without the valvecover, and all i saw was lobes flicking oil. Unfortunately, I do not have a vtec head on yet to try this out, but ive been studying it and I like this stuff because I'm into engineering.

Cheers to engineers.