i've done a ton of searching, but no solid posts on which forged pistons to use for an ls/vtec. i'm looking for 9-9.5:1(by weisco), do i use a vtec piston because of the valve relief's or can i use a non-vtec piston because they make the relief's deep enough anyway usually on a forged piston?? thanks for you help

 

not sure if this helps, but this is the lsvtec Viren built me. They are 9:1 compression edyne pistons. Thats all I know.

 

nice block whats your setup going to be?

 

WHen I bought my JE pistons for my ls/vtec a while back. THey had specially made pistons for ls/vtec's...call ARI.... http://www.autoraceparts.com

 

It depends on your compression ratio of the piston and/or the headgasket thickness. Since you can slap on vtec heads on ls blocks without any issues, you shouldnt have any issues. The only way to know for sure is to clay the motor and check the piston to valve clearance.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">The only way to know for sure is to clay the motor and check the piston to valve clearance.</TD></TR></TABLE>

Great Idea. http://www.c-speedracing.com/h...y.php

 

Im thinking I might have a simiar issue.
I run JE 9.8:1 GSR pistons in my LS. Using a stock thickness Cometic HP gasket. Im in the market for cams..using stock as of now. Im thinking that which ever cam i decide to use that the lift wont let the valves deep enough into the reliefs and they will hit. Shitty thing is, when building the motor I didnt clay it cause i didnt think i was going to have this problem. I did check piston to deck clearance and the least amount of clearance was 2 thousanths.
Also using 1mm over valves so that will drop them down a little further.
Im hoping Im not screwed here, I dont really want to open the motor back up---if I do I will probably go LS/VTEC, which I dont really want to do.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">It depends on your compression ratio of the piston and/or the headgasket thickness. Since you can slap on vtec heads on ls blocks without any issues, you shouldnt have any issues. The only way to know for sure is to clay the motor and check the piston to valve clearance.</TD></TR></TABLE>

my trouble is i don't have my pistons yet, to clay them. i know what comp ratio i want and i will us a stock headgasket thickness, probably cometic. for some reason i thought that there was an issue w/stock b18a pistons being very close, i could be mistaken though. i appreciate your guys help!

 

bump for more people... right now i'm thinking the weisco 81.5mm 8.5:1 w/cometic gasket, any other opinions?? thanks

 

i made this post ages ago, now i have my bottom end together. i wanted to clay the motor to make sure the clearance was good.

i put the whole motor together, made sure the vtec was activated with a pc of paper in the rocker, and turned the motor over. took it all apart and much to my suprise the clay wasnt even touched?? i used a stock used head gasket, made sure it was at tdc, cams lined up, etc.... even did it twice, haha. anybody help me out.

the pistons are weisco b18a low comp 8.6-8.9:1 or something
stock b16a head
stock used headgasket

 

bump for more info

 

I wouldnt be suprised, 8.6/8.9:1 and a B16 head . You C/R is pretty low man.

 

Yeah, with those pistons you shouldnt have any clearance issues. Why so low on the compression.....kind of a waste.

 

on my turbo Ls/Vtec motor i used a b16a2 head and 8.5:1 compression pistons and never had any clearance issues. no piston to valve contact either when i pulled the head. my friend mike had an all motor LS/Vtec using Civic type R pistons on Ls rods and there was minimal contact, but i recommend anyone going that high in compression to make sure you A) can afford to run on race gas if it is going to be a daily driver B) can have someone properly clay your pistons to confirm your safety level and C) pray you dont have valve float issues or its a guarantee you will bend or break something.
all motor or turbo, Ls/Vtec engines make a lot of power but being as there is no set handbook to refer when building one, the best thing to do is ask a LOT of questions and if you still have misgivings ask some more. but running 8:1 pistons you can run a lot of boost if thats any consolation

 

thanks guys, i'm pretty sure its fine, i was most concerned about the shape of the valve reliefs, compared to what the valves actually needed.
the pistons are 8.6-8.9:1 so with the smaller cc of the b16a head i should be on the high side of that. i'm willing to sacrifice a bit of power, so i can have a bit more room for error on the tuning side of things.

 

I use je 9:8:1 pistons in my ls block and I use b16a head. I dont have any problems with it yet. U should be fine. I got them for gsr.