Ok if you read my last post I am planning on building my 91 Si up for ECHC H4. The engine has almost 200k on it so its time to rebuild it. I am green on which maybe the best set of pistion's and rods. There are so many out there its very confusing.


Also any other sugestions would help.

Balance, blueprint, and have the head reworked are also on the list.

Thanx

 

http://www.nasaproracing.com/r...c.pdf

Scroll to Page 5.

 

I have the rules. I just mean is there some one brand of pistions or rods that are better, or something that I need to make sure that I do while the engine is out and apart.

Thanx

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vbspec &raquo;</TD></TR><TR><TD CLASS="quote">I have the rules. I just mean is there some one brand of pistions or rods that are better, or something that I need to make sure that I do while the engine is out and apart.

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

he's referring to this":

"Engines may be bored to a maximum of .040 inch over standard bore size. Factory replacement pistons or the exact equivalent shall be used. Exact equivalent shall be defined as the same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston."

So the answer is . . . . OEM Honda

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nonsense &raquo;</TD></TR><TR><TD CLASS="quote">So the answer is . . . . OEM Honda </TD></TR></TABLE>

Sort of...

 

The answer could be GX pistons

 

There was some discussion on this very subject recently...

https://honda-tech.com/zerothread?id=908722

It generated some good discussion and tips. I recently finished building my A6 to the H4/ITA rule sets. The bottom end, I built and is mostly by the book with a .020" overbore. OEM parts throughout. I sent the head off for the pros to take care of. With a few hundred street miles on it and one autocross, I am pretty happy so far. It gets its first track thrashing at VIR on Friday.

 

so GX pistons have "same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston" ?

if so then what makes them better??

 

http://www.d-series.org

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg1R &raquo;</TD></TR><TR><TD CLASS="quote">http://www.d-series.org</TD></TR></TABLE>

ok thanks, so, are they the same or different? I'm assuming that they are different therefore giving a performance andvantage (why else would you swap them in?). So they are different and that makes them illegal for use in a H4 car right? Or am I totally missing the point of the rules?

 

No H4 says OEM Honda not OEM Si the GX's are very different but I don't have the specs written down exactly so search on the site

 

But then that would be illegal, no? I think you missed that part somewhere in your interpretation of the rules.

"Engines may be bored to a maximum of .040 inch over standard bore size. Factory replacement pistons or the exact equivalent shall be used. Exact equivalent shall be defined as the same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston."

 

Rex....

I'm in Va Beach and have friends who will be up a VIR this weekend. I'm very jelous.


Question for you, Who did you sens your head to? Was it local?

Thanx

 

interpretation is the key

IE GX pistons are a replacment from Honda and so are the LS rods to make them work

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg1R &raquo;</TD></TR><TR><TD CLASS="quote">interpretation is the key

IE GX pistons are a replacment from Honda and so are the LS rods to make them work</TD></TR></TABLE>

no way. no way. you do that, and you will be in H1. absolutely. your min weight will only be 2000 lbs, as opposed to 2200 lbs for the B series cars and 2350 for the K series. have fun. thanks for playing!

todd

 

vbspec,

The head, intake, and TB all went to King Motorsports. Their service includes all head and intake work allowed for ITA/H4. They turned it around in 1 week and everything comes back looking like brand new. Nice folks to deal with. Their prices are on thier web site.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg1R &raquo;</TD></TR><TR><TD CLASS="quote">interpretation is the key

IE GX pistons are a replacment from Honda and so are the LS rods to make them work</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike P. &raquo;</TD></TR><TR><TD CLASS="quote">"Engines may be bored to a maximum of .040 inch over standard bore size. Factory replacement pistons or the exact equivalent shall be used. Exact equivalent shall be defined as the same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston."</TD></TR></TABLE>

read the WHOLE rule. the GX piston does not meet this criteria. like todd said, H1 for you. have fun!

nate

 

PM Travis, he just had a new motor built that he told me about last night. Didn't get a whole lot of details, but from the sound of it, it was done meticulously to the rules and is promising really good hp/tq numbers. I'll let him fill in details on who he uses because he informed me the guy is trying to get into building race motors. I guess we'll see how he does in September at PIR in Phoenix.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">
read the WHOLE rule. the GX piston does not meet this criteria. like todd said, H1 for you. have fun!
nate</TD></TR></TABLE>

it's not an aftermarket piston, it is a replacement piston and it does use all honda parts - there is also no specific statement that defines a h4 bottom end from an h1

exactly nowhere does it say that your Si model has to contain Si model pistons only OEM pistons

it also technically speaking allows for a JE piston of the same spec as the GX piston

I think you should read rule 2 again and understand all that it implies - from what I've seen more than a few other people have.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg1R &raquo;</TD></TR><TR><TD CLASS="quote">

it's not an aftermarket piston, it is a replacement piston and it does use all honda parts - there is also no specific statement that defines a h4 bottom end from an h1

exactly nowhere does it say that your Si model has to contain Si model pistons only OEM pistons

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

Does say this.

16.2 Hybrids Defined
a) A Hybrid will be defined as any Honda vehicle built with components that are sourced from a stock Honda vehicle of a different model, domestic market or generation.

So if the piston is from a different model, it's a hybrid, H1.

 

The piston used has to be dimensionally equivalent, and of equivalent weight to the Si piston as a whole to be legal. If JE makes a .040 over piston that meets the above criteria it is legal. IF a GX piston meets the above criteria it is legal (It does not).

Lets say you do use a different piston than Si...no matter what you use you can only raise the CR by 1/2 point anyway. So why not use the Si piston and shave the head? Guaranteed legal

There is also a part of the rule book, up front, that says if the rules don't specifically allow a modification or mix and match of parts or whatever...you can not perform said modification and call it "interpretation".


Modified by RexRacer19 at 8:01 PM 7/28/2004

 

I think the point that eg1R is trying to make is:

"Engines may be bored to a maximum of .040 inch over standard bore size. Factory replacement pistons or the exact equivalent shall be used. Exact equivalent shall be defined as the same dome/dish/valve relief configuration, weight, ring thickness and location, and pin location as the OEM replacement piston."

Factory replacement for what engine? Yes we all assume the rules mean "Factory replacement pistons for the engine that came with your car" but alas it doesn't say that so it is open to be interpreted as "any factory replacement pistons" even if from a different engine.

HOWEVER as Geezer mentioned:

"16.2 Hybrids Defined
a) A Hybrid will be defined as any Honda vehicle built with components that are sourced from a stock Honda vehicle of a different model, domestic market or generation."

Which would be grounds for protesting if you used the above piston loophole.

Every set of rules has it's own loopholes that most people don't abuse it until "That Guy" comes along and has to exploit it, then the rules get revised. Don't be "that guy"

 

OK, now I'm completely confused.

Say I take my stock Si engine to a builder and want a .20 overbore... what pistons would a reputable builder use to make this engine legal?

Danke'

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by emwavey &raquo;</TD></TR><TR><TD CLASS="quote">OK, now I'm completely confused.

Say I take my stock Si engine to a builder and want a .20 overbore... what pistons would a reputable builder use to make this engine legal?

Danke'</TD></TR></TABLE>

Stock/OEM replacement pistons (for the engine which is in question), more than likely sourced from Honda.

The only reason to go with an after-market OEM-style piston - they potentially would be guaranteed at the minimum end of the legal weight spec and the set would be balanced (assuming of course the after-market piston supplier is supplying sets for race engines).

 

So would the pistons be the same size?... that doesn't make sense to me... that would just be asking for the piston rings to deal with the extra room?

... or are people sleeving after boring over?...

My thinking is you would have to use a slightly larger piston diameter, but retain, like said in the rules, every other characteristic of the piston... weight, dome, etc.