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Curious George
'99 LX Civic Sedan
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3,569 Posts
Discussion Starter #1
I tried something tonight that I wanted to do since long ago.

I took a y8 head, and fit the y7 rocker arms assembly, to get advantage and benefit of y8 ports size and combustions chamber shape, and y7 lightweight aluminum rocker arms, less moving parts, larger cam tappets and non vtec cheaper regrind ( I will use back my bisimoto stage 2 :) ). It's like TODA vtec killer cams to comparate with a B-series.



You need to use:

- y8 head casting (you can use valve and springs you want but remember y8 intake side springs are stiffer, two set of them make a nice upgrade)

- 5 y8 cam holders (it's bored with the head you have to use it to get right cam clearance and the dizzy side one have oil pass in it that y7 can't block we also need to use it, well every y8 holders.)

- If I make no mistakes y7 holders bolts too. (try it I think they are the same)

- both y7 rocker shaft in the right position (you'll see oil passage must be in y7 rocker arm center.)

- y7 rocker arms/rocker springs/spacers


- vtec selenoid hooked on the head, but electric unplugged.




Everything 'mecanic' is fine , you got a frankeinsten head. I didn't put it in the car yet, I have to study and check about the oil passages a bit, but it looks to be OK no oil holes seems to be unplugged with those parts.


I will post pictures soon as possible.



PS- If somebody have y5 head parts, I'll be willing to buy it, I have some test to do with them...
 

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Well?
Joined
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10,814 Posts
damn thats nifty, i wanna see pics of this man.
 

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Curious George
'99 LX Civic Sedan
Joined
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3,569 Posts
Discussion Starter #11
so now vtec is locked open? as in its in vtec 24/7 now?
No and no. You use the y7 rocker arm, no vtec. Y7 valve train means no vtec, you can run y7 cam only. You have to let the vtec selenoid bolt there, but no need to be hooked to the ecu. It's like running y7 head with y8 casting. that's it.

24/7, I don't let my engines run all the time. Maybe somebody else never stop it to adjust valve lash, or wear full face helmet to prevent blindness.
 

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OMG TOTALLY COOL TITLE!!!!
88 y49 crx
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3,888 Posts
now would this kinda setup work with the y7 cam and rocker arm assembly in the y5 head casting? doesnt the y5 bump compression a bit more than the y8?
 

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Curious George
'99 LX Civic Sedan
Joined
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3,569 Posts
Discussion Starter #13
now would this kinda setup work with the y7 cam and rocker arm assembly in the y5 head casting? doesnt the y5 bump compression a bit more than the y8?
I dunno about the combustion chamber spec of the y5 head. I looked for the y8 head for the ports size first and combustion chamber shape, not really in compression bump, because I'm goin turbo ;)
 

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Registered
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873 Posts
Y8 & Y5s have the exact same casting / design --> P2J-xx

They just differ in the valvetrain system and of course cam design.

Y5 = 9.4:1 static c.r.
Y8 = 9.6
(at least from what's written in the spec sheets)

i'm kinda thinking dynamic c.r. could come out just a liiiitle higher in the Y5 coz of the low cam lobe design differences between the two. just my .02
 

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873 Posts
Belette, could you give us an update if the Y7's tappet adjusting screw line up perfectly with the Y8 valve tips....?
I'm curious to know if the rocker arm geometry is dead on in this match-up.. (Y8 valve angles + Y7 rocker arm movement angles = ??)
 

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Curious George
'99 LX Civic Sedan
Joined
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3,569 Posts
Discussion Starter #16
Belette, could you give us an update if the Y7's tappet adjusting screw line up perfectly with the Y8 valve tips....?
I'm curious to know if the rocker arm geometry is dead on in this match-up.. (Y8 valve angles + Y7 rocker arm movement angles = ??)
It looks like perfect in line, valve are in the same location in y7/y5/y8/z6. I will check it this weekend more in detail, but I looks really good :)
 

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Curious George
'99 LX Civic Sedan
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3,569 Posts

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Registered
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3,314 Posts
Can you use the y5 rollers with true VTEC?
 

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Curious George
'99 LX Civic Sedan
Joined
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3,569 Posts
Discussion Starter #20
I never tried. I will do it if I cn get a set of y5 valvetrain ;)
 
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