i had always heard that .040 was the max oversized allowed by many racing sanctions. i am rebuilding my B16 and would like to use CTR pistons, which are available up to 81.50 millimeter bore. (correct me if i am wrong.) i have a friend trying to tell me that it is possible to bore STOCK cylinders up to 83 millimeters. this just doesn't seem correct to me. i know that jun strokers use an 82 mm piston, but i don't know if that is with a stock sleeve. thanks.

 

please USE search FOOL! i swear there was just a post like this yesterday.
and 82mm is the max amount... anything more & your asking for trouble

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Charlie Moua &raquo;</TD></TR><TR><TD CLASS="quote">please USE search FOOL! i swear there was just a post like this yesterday.
and 82mm is the max amount... anything more & your asking for trouble</TD></TR></TABLE>

A. This is true.
B. You are incorrect, CTR pistons in their largest size (i.e. overbore) are 81.25 mm.

 

i was sure i had seen the ctrs in a .5 oversize. ah, well.

any reccomendations for a B16 with jun3's, from compression calculators it seems that there i not much of an increase (10.4 to 10.8) with ctr pistons. i definitely need rings when i build the motor, and i really want to get to an upper 11 compression ratio to keep the cams happy.

i would like to use an oem head gasket, they seem to seal and last the best. are the mugen two layer gaskets a good idea? i am strongly considering arp head studs to hold it all together.

 

I wouldnt go over OS bore...only because 84mm+ needs resleeving before stock sleeves will crack under high pressure....from what ive read anyways....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91hatchattack &raquo;</TD></TR><TR><TD CLASS="quote">i was sure i had seen the ctrs in a .5 oversize. ah, well.

any reccomendations for a B16 with jun3's, from compression calculators it seems that there i not much of an increase (10.4 to 10.8) with ctr pistons. i definitely need rings when i build the motor, and i really want to get to an upper 11 compression ratio to keep the cams happy.

i would like to use an oem head gasket, they seem to seal and last the best. are the mugen two layer gaskets a good idea? i am strongly considering arp head studs to hold it all together.</TD></TR></TABLE>

You will be above 11:1 w/ ctr's, that calculator isn't accurate when measuring ctr's due in part to the fact that the piston sits slightly higher on the rod w/ ctr's as opposed to other b series pistons.

 

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

A. This is true.
B. You are incorrect, CTR pistons in their largest size (i.e. overbore) are 81.25 mm.</TD></TR></TABLE>

b) I never said that CTR pistons come in 82mm? WTF
he asked what is the safest he could bore out to on stock sleeves.

 

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

b) I never said that CTR pistons come in 82mm? WTF
he asked what is the safest he could bore out to on stock sleeves.</TD></TR></TABLE>

Chill out. His "A." was referring to you and his "B." was referring to the original poster.

 

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

b) I never said that CTR pistons come in 82mm? WTF
he asked what is the safest he could bore out to on stock sleeves.</TD></TR></TABLE>

I wasn't talking to you x 1000.

 

anything bigger than 82mm, you'll be risking the sleeves.

ctr is 81.00 std or 81.25 os

i run 81.50 wiseco pistons. no problems.

 

what compression do your 81.5 wiseco's make? are they the forged aluminum set? i would like to use lighter than stock pistons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoshikatu &raquo;</TD></TR><TR><TD CLASS="quote">anything bigger than 82mm, you'll be risking the sleeves.

ctr is 81.00 std or 81.25 os

i run 81.50 wiseco pistons. no problems.</TD></TR></TABLE>

Damn I asked this question a while back, but I was told 81.25 was largest. BUT I was going to do 81.5mm anyway, how many miles does yours have? I only want around 11.5cr.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91hatchattack &raquo;</TD></TR><TR><TD CLASS="quote">what compression do your 81.5 wiseco's make? are they the forged aluminum set? i would like to use lighter than stock pistons.</TD></TR></TABLE>

I use Endyn/Wiseco 11.3:1 pistons but I have 1-layer headgasket so my CR is
about a little over 12:1. They weigh about 280-300 gram, which is about 10 gram lighter than a Type R piston. Yes, they're forged. not sure what exact type of material they're made out of though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Twenty36_1 &raquo;</TD></TR><TR><TD CLASS="quote">

Damn I asked this question a while back, but I was told 81.25 was largest. BUT I was going to do 81.5mm anyway, how many miles does yours have? I only want around 11.5cr.

</TD></TR></TABLE>

Yea. they're wrong. my machine shop can bore it to 82mm. if you run forced induction, then i'll keep 81mm. 81.50 is the most i'd push. 81.25 sounds good
too since you can get type r pistons in that size over the counter. i am running
N/A setup so I don't think 81.50 is going to give me any sleeve problem given
the fact that i've done all the bottom end machine work. so far 1000 miles.
dyno'ed close to 190whp and 140wtq. raced it for 2 days, lot of 9-10k revs,
no problems.