my setup has gotten me some pretty close piston to valve clearance #'s ...and i need some opinions on what kind of cam im gonna be able to go with for my setup so far....

b17 block and head.
bored over...81.5mm arias pistons
block has been decked i believe 0.010 thousands.
.43mm headgasket
head has also been been milled 0.030 thousands
shotpeened/polished rods
1mm oversized valves/springs/etc. (BUT NO CAM YET!!!!!)
port/polish
and a bunch of other goodies/balanced/blueprinted
.....ruuning about 11.6 to 1 CR

when putting the motor together a clay test was made and with this setup i came out with a piston to valve clearance of "0.080" thousands on intake side

MY QUESTION IS........how much/what kind of a cam can/should i go with?????!?!? the car is just waiting for a cam to be dropped in!

any input/suggestions would be huge help. thanks.



Modified by GSR4U2NV at 7:04 PM 5/14/2005

 

If there's no cam in there yet and you have 80 thousandths valve to piston clearance, you can't run ANY cam. How far are the valves opening? What cam is in there, if any?

And remember, 0.010 thousandths = 0.00001"... It's either 10 thousandths or 0.010".

Oh, and welcome to Honda-Tech!

 

i have the factory b17 gs-r cams in it as of now....and that 80 thou clearance is with vtec lobe activated? your sayihng i cant go with any cam>???

 

NEED SOME MORE HELP HERE PEOPLE.......WAS ACTUALLY THINKING OF THROWING IN A SET OF CTR CAMS! WILL I HAVE ENOUGH CLEARANCE? I BELIEVE THEY JUST HAVE AN EXTRA 1MM LIFT OVER MY GS-R CAMS 1MM= 43 THOU NO?? SO I SHOULD BE LEFT WITH JUST UNDER 40 THOU CLEARANCE TO SPARE?

 

you need at least .100" of piston to valve clearance. you can gain more clearance by having the valve pockets on piston cut deeper and/or cut some material off the face of the valve. what is your piston to deck clearance? the head gasket(.021" thick) you have now may not give you enough piston to head clearance as well, you want at least .040" piston to head clearance.

 

well the motor is running in the car and there are no problems whatsoever clearance wise right now...i just desperately want a cam in there. right now as it sits im putting 178whp (factory cam).

 

BUMP...NEED MORE OPINIONS PLEASE...

 

why mill down 40 thous worth ? to gian compression ?

use a thicker headgasket ... cometic sells various thickness. how much is the piston sticking out the deck ?

 

AT THE TIME OF THE ENGINE BUILD I WAS ON A BUDGET AND BUILT THE ENGINE AROUND THE FACTORY CAM....AND NOW I WOULD JUST LIKE TO BE ABLE TO THROW A CAM IN BUT IM UNSURE OF WHAT I CAN GO WITH IF ANYTHING AT ALL. AND IM NOT EXACTLY SURE HOW MUCH THE PISTON STICKS OUT THE DECK.

 

Ok well ive thought about it and well COMETIC does seel different thicknesses of headgaskets....so after thinking about it, what thickness of headgasket should i go with and still run safe clearances if i decided to throw in SK2 stage 2's????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSR4U2NV &raquo;</TD></TR><TR><TD CLASS="quote">Ok well ive thought about it and well COMETIC does seel different thicknesses of headgaskets....so after thinking about it, what thickness of headgasket should i go with and still run safe clearances if i decided to throw in SK2 stage 2's????</TD></TR></TABLE>

65 to 70 thou gasket should clear ... assuming you're using stock pistons, i.e. stock valve reliefs.

Greg

 

no im not using stock pistons...they are arias 81.5mm pistons and the compression hight on them is 1.175 if that helps.....because im not sure myself.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSR4U2NV &raquo;</TD></TR><TR><TD CLASS="quote">no im not using stock pistons...they are arias 81.5mm pistons and the compression hight on them is 1.175 if that helps.....because im not sure myself.</TD></TR></TABLE>

stock compr height is around 1.180 so you gain about 5 thou in the hole, so still aim for a good 70 thou gasket and find out from arias if your pistons valve reliefs are as big as stock or smaller ...

greg

 

sorry man......yes my arias piston valve reliefs do accomodate oversized valved which i have. so i guess a 70 thou headgasket from cometic should do it? do you have any idea what kind of clearances i should be left with if i do go with the skunk2 stage 2 cams?

 

Well i guess getting this 70 thou head gasket will give me back some from what i took off of the head and block so it will be as though i didnt mill the head and deck the block whatsoever right?