ok, setup is ls/vtec, gsr head, 84.5mm bore. as i understand it, the ls piston is .019" or so down in the hole. This will be .002" out of the hole, which by rough estimate will yield about .5 compression increase. Should I look into a thicker hg or will stock suffice assuming p2v clearance checks out ok?
thanks,
J

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">ok, setup is ls/vtec, gsr head, 84.5mm bore. as i understand it, the ls piston is .019" or so down in the hole. This will be .002" out of the hole, which by rough estimate will yield about .5 compression increase. Should I look into a thicker hg or will stock suffice assuming p2v clearance checks out ok?
thanks,
J</TD></TR></TABLE>

OK,is it .019" in the hole or .002" out.It can't be both.Anyway you need at least .035" piston to head no matter how you get there.

 

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

OK,is it .019" in the hole or .002" out.It can't be both.Anyway you need at least .035" piston to head no matter how you get there.</TD></TR></TABLE>

the factory LS is about .0019 in the hole. this motor will be .002 out of the hole. my guesstimation is a .5 increase in c/r from listed by the piston mfg, so the estimate, considering a stock hg is around .029" depending on who you talk to, i need a .055" hg?

 

.002" out of the hole + .035" clearance = .037" gasket thickness.

 

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

you need at least .035" piston to head no matter how you get there.</TD></TR></TABLE>

you sure?

 

how much thickness does adding another middle layer to a stock hg add?

 

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

you sure?</TD></TR></TABLE>

That's what I have always used as a guide line.It's not an absolute.

 

i guess everyone has their own ideas. i am getting ranges from 30 to 40 thou. i will know more after i finish assembling and measure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">how much thickness does adding another middle layer to a stock hg add?</TD></TR></TABLE>

The OEM gasket is .028"

I added another OEM middle layer one time and it was around .036" uncompressed.

 

Doing some reading here in the am forum and all of a sudden I'm not so worried. Seems there are guys here running stock hg with ctr pistons in LS setups, which is .010" out of the hole by my math, plus the dome. This engine is going to be low comp dish piston.

 

You should be fine with a dished piston. I am .007 in the hole and using a stock headgasket but have a fairly large set of cams compared to what turbo cars run and I still have plenty of clearance when the intake valve chases the piston down the bore.


I would check it just to be sure because it's quick however and an old stock HG is always laying around somewhere.

 

ok. cams are nothing crazy, basically CTR with a tad more lift.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">Doing some reading here in the am forum and all of a sudden I'm not so worried. Seems there are guys here running stock hg with ctr pistons in LS setups, which is .010" out of the hole by my math, plus the dome. This engine is going to be low comp dish piston.</TD></TR></TABLE>

Most of these people are using b16 heads without quench pads.

 

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

Most of these people are using b16 heads without quench pads.</TD></TR></TABLE>

True. I guess I go with the .040" Cometic gasket and pray it holds.