ok so i screwed up
got pct pistons installed in an ls
the compression is way too high to be a DD

i was going to get the thickest HG to lower the CR

will this work also what other options do i have?

 

What is your current CR and How much do you want to drop?

 

with an OEM HG its +13:1
i want to drop to 11.5-12:1
so i will be able to run pump gas 91-94 oct

 

you can always just retard the timing some, too.

*edit* in addition to the thicker HG *edit*

 

how did you get the wrong pistons?

 

i ordered pct pistons on purpose but didnt do enough research before i bought them and took them to the machine shop to be installed

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AccordSleeperZzZ &raquo;</TD></TR><TR><TD CLASS="quote">you can always just retard the timing some, too.

*edit* in addition to the thicker HG *edit*</TD></TR></TABLE>

And some big cams can bleed off some compression.
Im running a .074" HG cause I had a similar issue. The spare block I bought was decked to hell, probably at least .02-.03" cause my pistons came out the deck 0.005-.008"

 

i ran pct pistons in my ls motor with a ls head, and i ran crower 403 cams with no problem. i ran 91 octane gas all the time and never had a problem of pinging.

 

What sort of head are you using?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by o5mar1 &raquo;</TD></TR><TR><TD CLASS="quote">i ran pct pistons in my ls motor with a ls head, and i ran crower 403 cams with no problem. i ran 91 octane gas all the time and never had a problem of pinging.</TD></TR></TABLE> What was your final measured static compression? Did you close up the cam center-lines to bleed off some compression? What was the final timing number? Did you have to run it rich?

 

u built the cliff... myt aswell jump? lol kidding..

anyways.. havnt seen any mention of tuning.. was it tuned? to justify the needing to drop compression?&gt; cuz for sure any comp high enough + no tune = too much comp lol..

would also answer donF's questions as that would help figure out sum stuff

 

it was a 97 ls motor. the compression calculators said it was like 12.5 or something like that.I ended installing the pistons first cause i needed new rings anyways with the stock cams and theye didint hit at all. than about a month later i installed the cams and i turned the motor by hand to see if it was hard or anything and it wasant. I used to rev the motor to 8k rpm when i raced didint have an issue, oh yeah and i was runing hondata s300 at the time too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by o5mar1 &raquo;</TD></TR><TR><TD CLASS="quote">it was a 97 ls motor. the compression calculators said it was like 12.5 or something like that.I ended installing the pistons first cause i needed new rings anyways with the stock cams and theye didint hit at all. than about a month later i installed the cams and i turned the motor by hand to see if it was hard or anything and it wasant. I used to rev the motor to 8k rpm when i raced didint have an issue, oh yeah and i was runing hondata s300 at the time too.</TD></TR></TABLE>

What CR calculator did you use? I thought an LS w/ PCT's would be more like 13:1 if not higher.

 

hey o5mar1 or any1 else.. do you think i would have trouble running p30's and crower 404's in a LS block?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AccordSleeperZzZ &raquo;</TD></TR><TR><TD CLASS="quote">you can always just retard the timing some, too.

*edit* in addition to the thicker HG *edit*</TD></TR></TABLE>

Retard the cam timing or the ignition timing?

once i get every thing back from the machine shop ill see if i truly see if i need a thicker HG cuz i ve gotten different answers on piston to deck height

for now the head is gonna be stock with a valve job and minor port but gonna upgrade to 404's with springs and retainers some time

 

he means ignition timing. you can always clay the engine to make sure it wont hit