hybrid_vtec

So everyone wonders what this magical nonvtec b-series head we nonvtec guys talk about, but not many ppl have seen, called the P8R. Well I have taken the time to take some pics for you guys showing the difference with this head. Most LS and B20 heads are typically known to have poor flow until headwork is done, and have smaller intake valves compared to the vtec conterparts(33mm vs. 31mm). Well this head has 33mm intake valves from the factory as well. The ports are suppossedly bigger, but when I measured a the P8R against the P75(LS head) with a set of calipers they both turned out to be the same dimensions(52mm wide).


So does this head really flow similiar to a Vtec head like some claim? Answer is I do not know, but hopefully I can get this head flow benched vs a stock B16 head; which should make some interesting results!

Since this head comes off of a B20 it has 84mm combustion chambers which means that it cannot be used on an LS Block. So hopefully I will find a way to get my hands on a B20 block and put this head to use.


Here is a pic of the bottom of the head. Notice the stamp at the bottom, P8R.


Here is a pic fom the intake side, notice the stamp again as well.


Here is the date stamp on the block indicating it was made in 1997, in which it is said to have only come on the 98 model B20's in japan deeming why it is so rare!


Now for the good stuff! Here is a 31mm LS Intake Valve compared to the P8R intake valves.


Here is an ITR intake valve from the set that I have laying around compared to the P8R intake valve. Looks like 33mm to me!



Well I hope you guys look at this and will now know what a P8R head next time we nonvtec guys talk at it when you tell us how much our builds suck b/c the head does not flow like Vtec counterparts.

SPOON_FED_DC_2

Looks very interesting i would like to see how its benchmark is compared to a b16 head.

athoughts

GOLDBERG

when yah plannin on flow testin it?

hybrid_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GOLDBERG &raquo;</TD></TR><TR><TD CLASS="quote">when yah plannin on flow testin it? </TD></TR></TABLE>

when I get some money or a hook up!

RMF

Are the stems 5.5mm like the Bseries heads or 8mm like the LS.And is the rockers and shafts the same config.and ratio. One more thing,What I.M. bolt pattern is it ?B16,GSR,or only B20.

hybrid_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RMF &raquo;</TD></TR><TR><TD CLASS="quote">Are the stems 5.5mm like the Bseries heads or 8mm like the LS.And is the rockers and shafts the same config.and ratio. One more thing,What I.M. bolt pattern is it ?B16,GSR,or only B20.</TD></TR></TABLE>

Everything is the same as the LS! The valve stems are the same as LS(wider than Vtec valves). It still has a 1.75 rocker ratio, and it came with a B20 IM that has the same bolt design as the LS IM. The Valvespring installed height is 44mm, same as the P75 heads, while the PR4(older LS head) is 43mm.

BlueTeg

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">
The valve stems are the same as LS.
The Valvespring installed height is 44mm, same as the P75 heads</TD></TR></TABLE>

Rick: do you have any pictures to confirm?

hybrid_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlueTeg &raquo;</TD></TR><TR><TD CLASS="quote">

Rick: do you have any pictures to confirm?</TD></TR></TABLE>

I can take some pictures, if you like.

BlueTeg

iTrader: (2)

If you would, it would be greatly appreciated.

Jeter2NYC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">

I can take some pictures, if you like.</TD></TR></TABLE>

yes please do

hybrid_vtec

I will have pics up tomorrow.

not so civic

hmmm i could use one of those things.

Pandahatch

Wierd I have one of those heads sitting in my basement and never thought anything about it. I wonder if this means the valve reliefs in the pistons are bigger also?

hybrid_vtec

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Wierd I have one of those heads sitting in my basement and never thought anything about it. I wonder if this means the valve reliefs in the pistons are bigger also?</TD></TR></TABLE>

More than likely yes!

BlueTeg

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PandaHatch &raquo;</TD></TR><TR><TD CLASS="quote">Wierd I have one of those heads sitting in my basement and never thought anything about it. I wonder if this means the valve reliefs in the pistons are bigger also?</TD></TR></TABLE>

They're not. Both the P3F & PHK piston still have the shallow valve relief pockets in them. The valve reliefs in the P3F and PHK pistons don't start to become a problem until you start going with a really aggressive cam (greater than 11.5mm of lift) and/or (a) advance the intake cam (b) mill the head (c) use a thinner HG.

hybrid_vtec

I dont know b/c I did not see the block that this head came of of or the pistons that were in it. It would only make since though that the pistons would be different.

BlueTeg

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_vtec &raquo;</TD></TR><TR><TD CLASS="quote">I dont know b/c I did not see the block that this head came of of or the pistons that were in it. It would only make since though that the pistons would be different.</TD></TR></TABLE>

There are only two pistons made for the usdm and jdm B20 blocks. PHK and P3F. There wasn't a need for Honda to make a 3rd piston with wider/deeper valve reliefs since the existing pistons could accomodate the 33mm valves already.

When using an oem nonvtec cam, both pistons can clear a 33mm valve with ease. Even if you "push it" and use a cam with a fairly aggressive lift (11-11.5 mm of lift on the intake side) you'll still clear both pistons without contact assuming that you haven't advanced the intake cam, haven't milled the head excessively and using an oem HG.

91sihatch

Interesting thread. Thanks hybrid_vtec

racer4life

Thank you 4 the lession

5thgenallmotor

Ok maybe this is what I got from osaka JDM motors one time... Does this rare head come with a ls style (short) intake amnifold vs the Crv Manifold (real tall) I am not really a non-vtec guy but thanks for the info!

hybrid_vtec

No, mine came with a really tall IM

Pandahatch

Ditto^^^