IT Piston Rules - Overbore

[mowog]

I can honestly see both sides of this, so now I have a different question. How SHOULD the rule be written based on what the competitors want, with input of course from the AC and CRB. I say based on the competitors because ultimately this is a club, and therefore in my opinion the goal shouldn't be nit-picking rules with the intent of protesting others, the preparation rules should be based on creating a level playing field, and contain allowances that participants feel are needed. I know I wouldn't want to play with lots individuals (stewards and competitors) whose sole purpose seems to be disecting rules to the point where everyone eventually quits cause it just isn't fun anymore.

So with that in mind, is it fair for some to be able to bore to .040, and others less, if at all? How many want to move up to Production, or more importantly run both classes? In Prod, you can overbore .047. Cast pistons (few, if any stock pistons are forged) require a fair amount of clearance. Some stock .040 pistons will require enough clearance to make the motor illegal without any wear. After a year or two on most motors bored just to .040, the motors will be worn to illegal limits, and therefore junk because the wear will take them over the .040 limit. This was the reason other classes (Prod and GT to name 2) allowed a little bit of leeway. So now if people can't bore beyond .040, regardless of the stock piston issue, there are going to be some illegal cars out there. Is that what everyone wants? Now look at those wanting to make the jump to Prod, or run both. I really think the rules need to be closer together here to encourage people to run both classes. How about we get back to being a club for the members. Once it's determined what the majority want, then maybe TOGETHER we can work on the wording of the rule(s) to make it clearer for all.

 

[Joe Harlan]

Originally posted by mowog@Nov 18 2005, 10:26 AM
I can honestly see both sides of this, so now I have a different question. How SHOULD the rule be written based on what the competitors want, with input of course from the AC and CRB. I say based on the competitors because ultimately this is a club, and therefore in my opinion the goal shouldn't be nit-picking rules with the intent of protesting others, the preparation rules should be based on creating a level playing field, and contain allowances that participants feel are needed. I know I wouldn't want to play with lots individuals (stewards and competitors) whose sole purpose seems to be disecting rules to the point where everyone eventually quits cause it just isn't fun anymore.

So with that in mind, is it fair for some to be able to bore to .040, and others less, if at all? How many want to move up to Production, or more importantly run both classes? In Prod, you can overbore .047. Cast pistons (few, if any stock pistons are forged) require a fair amount of clearance. Some stock .040 pistons will require enough clearance to make the motor illegal without any wear. After a year or two on most motors bored just to .040, the motors will be worn to illegal limits, and therefore junk because the wear will take them over the .040 limit. This was the reason other classes (Prod and GT to name 2) allowed a little bit of leeway. So now if people can't bore beyond .040, regardless of the stock piston issue, there are going to be some illegal cars out there. Is that what everyone wants? Now look at those wanting to make the jump to Prod, or run both. I really think the rules need to be closer together here to encourage people to run both classes. How about we get back to being a club for the members. Once it's determined what the majority want, then maybe TOGETHER we can work on the wording of the rule(s) to make it clearer for all.

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Chris the issue I have with that is guys like me will build them to that limit instead of worrying about a worn out bore. I can show you the build sheet for my 1600 roadster pistons if you like. The point is it wouldn't matter the spec, somebody would try to take advantage of it. I pesonally thinkthe option for those that can't get a 040 piston from the factoryis. Submit a request for allowance. Provide specs on the factory STD,.010,.020 including weights. This would allow the adhoc to come up with a spec and add it to the spec line.

 

[Geo]

Originally posted by mowog+Nov 18 2005, 10:26 AM-->

I can honestly see both sides of this, so now I have a different question. How SHOULD the rule be written based on what the competitors want, with input of course from the AC and CRB. I say based on the competitors because ultimately this is a club, and therefore in my opinion the goal shouldn't be nit-picking rules with the intent of protesting others, the preparation rules should be based on creating a level playing field, and contain allowances that participants feel are needed. [/b]

I agree with you completely. I too see both sides of this. At first I thought Darin was nuts. Then, as I pondered and read more carefully, I think he's right. But I also think Kirk an Greg are right. But then I think Darin is right about trying to match non-existing specs. Clearly a quandry. In the end, whatever happens there is likely to be a group of people who will be quite unhappy.

Originally posted by mowog@Nov 18 2005, 10:26 AM
So with that in mind, is it fair for some to be able to bore to .040, and others less, if at all?

I wonder how the rotary guys feel about this? I wonder how those with carbs feel about ECU allowances for some (actually I don't, it's been covered quite well - this was rhetorical)? In the end there will always be those can take advantage of a rule while others cannot. Unless we want to race spec, this will always be the case.

<!--QuoteBegin-mowog@Nov 18 2005, 10:26 AM
Some stock .040 pistons will require enough clearance to make the motor illegal without any wear. After a year or two on most motors bored just to .040, the motors will be worn to illegal limits, and therefore junk because the wear will take them over the .040 limit. This was the reason other classes (Prod and GT to name 2) allowed a little bit of leeway.

Actually, bores can increase at the same rate at the pistons, so both increase in diameter 0.040" so this is no mismatch of piston to bore regarding legality.

Hey, if someone builds a fresh engine to 0.040" over and it wears beyond the limit, thems the breaks for racing on the edge. I feel no sympathy. They knew that was a possibility before they started. AS for allowing boring beyond 0.040" to allow for greater wear, at what point do we stop? When the 0.047" pistons wear, will Production increase the limit? I doubt it.

Originally posted by mowog@Nov 18 2005, 10:26 AM
So now if people can't bore beyond .040, regardless of the stock piston issue, there are going to be some illegal cars out there. Is that what everyone wants?

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I'm not seeing the issue here. See above.

 

[Bill Miller]

Originally posted by GregAmy@Nov 18 2005, 12:24 AM
Well, then, let's stop cramming. By bringing up this overtly-literal "interpretation" of the overbore rule, you are, de facto if not du jure, already changing the rule.

I'm personally aware of more than one person who are driving cars built with +.040 bore pistons that meet the intent of the rule but whose cars' manufacturers do not offer a +.040 bore piston. These folks are as squeaky clean as you can imagine, with pistons that meet every implied intent of the rule, and have made it a specific point to be so. You are now telling them they're illegal.

If this stands, you are asking them to spend FAR more money to "rectify" this situation than what one would have to spend if you rescended the Motec and/or spherical bearings allowances. If you're OK with cramming the +.040" bore genie back into its bottle, then we've got a HELL of a lot more rules to talk about... - GA

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Greg,

The rule is pretty clear. It says "Factory oversize replacement pistons or their exact equivalent shall be used." If you can't get something that meets that rule, and elect to use just any .040-over piston that fits, you are putting yourself at risk. And in the case you cited above, they are in fact in violation of the rule. How much it would cost them to bring their motor into compliance really has no bearing on the subject, and is a risk that you accept when you make your own interpretations of what rules 'really mean'. And while it's not really germane to the discussion, what's a fresh short block cost, vs. the MoTeC system? I'd really be surprised if the short block cost FAR more than a MoTeC. Same ballpark (~$2500?) maybe.

 

[Greg Amy]

Sorry, Bill, but in lieu of a point-by-point reply, I'm just gonna say "you're full of water". Overboring +.040 has been "legal" for EVERYONE since at least 1984 when I started racing IT (and I've got a copy of the rulebook somewhere around here).

You wanna start "interpreting" the rules differently than the to-most-folks-obvious intent, you're free to do so, but until you drop the $25 it'll be nothing more than an Internet forum pissing match... - GA

 

[dj10]

Originally posted by Banzai240@Nov 18 2005, 10:58 AM
Kirk,

I agree and we share the same understanding of the rule in this case...  It's only in the cases where someone uses the fact that there is NOT a factory replacement available as reasoning to make something other than the specs would limit one to that this really is an issue, because to prevent THIS from happening (via protest, or ???), it brings the specific wording into light, and suddenly those of you out there who are built to the "spirit" of this rule would come into question...

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Darin,
You've seen all these posts, my question is since you are on the board, what do you propose now?
dj

 

[Knestis]

Having thunk a little more about this point, it hit me. IT JUST DOESN'T MATTER what the rules say!

The culture of IT is such that it's going to take a pretty huge kerfuffle for a protest to ever get to the point of SEEING a set of pistons - let alone actually weighing or measuring them. The de facto solution is that each of us runs what might be consistent with our values and view on the rules, or what we think we can get away with.

My last engine had the original, 129K-mile slugs. The new one will have silly-expensive, German quality factory oversize units. Neither decision was based on a strict reading of the rules, I'm afraid. The guy who would have ordered super-light, forged, extra-zoomy pistons for the same engine would have done so whatever the rule says.

Kirk (who is getting less NERDLY every day)

 

[Andy Bettencourt]

Originally posted by Knestis@Nov 19 2005, 11:52 AM
Having thunk a little more about this point, it hit me. IT JUST DOESN'T MATTER what the rules say!

The culture of IT is such that it's going to take a pretty huge kerfuffle for a protest to ever get to the point of SEEING a set of pistons - let alone actually weighing or measuring them. The de facto solution is that each of us runs what might be consistent with our values and view on the rules, or what we think we can get away with.

My last engine had the original, 129K-mile slugs. The new one will have silly-expensive, German quality factory oversize units. Neither decision was based on a strict reading of the rules, I'm afraid. The guy who would have ordered super-light, forged, extra-zoomy pistons for the same engine would have done so whatever the rule says.

Kirk (who is getting less NERDLY every day)

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Ya but there are SOME of us who want the zoomiest stuff WHILE being within the rules. I take no pride in winning while cheating. It's empty and shallow.

I have decided to buy the Mazda .020 factory overbore pistons from Mazdacomp. $40 each. For me to have .040 versions made that are NOT lighter than a stock slug is WAY too expensive for the benefit I would get from the extra .020. Plus it allows me to overbore this block again when I pop it trying to keep up with the HondAcuras.

It's been a good debate. People will do what they want, you are right Kirk, but hopefully, if the rules are clear, more people will follow them.

AB

 

[Joe Harlan]

Originally posted by Andy Bettencourt@Nov 19 2005, 10:28 AM
Ya but there are SOME of us who want the zoomiest stuff WHILE being within the rules.  I take no pride in winning while cheating.  It's empty and shallow. 

I have decided to buy the Mazda .020 factory overbore pistons from Mazdacomp.  $40 each.  For me to have .040 versions made that are NOT lighter than a stock slug is WAY too expensive for the benefit I would get from the extra .020.  Plus it allows me to overbore this block again when I pop it trying to keep up with the HondAcuras. 

It's been a good debate.  People will do what they want, you are right Kirk, but hopefully, if the rules are clear, more people will follow them.

AB

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Just a thought here. All else being the same. .040 is worth .1 compression points on a L24 Datsun over .020..

 

[lateapex911]

Well, thats the nut of it all, right? If you can take advantage of the extra displacement, what do we really get?? How much torqe and power does it result in? And of course, what does that mean to lap times?

Yes, Kirk, of course it is a moot point among a certain part of the group, but I think there is a large group that uses the rules as the fromework for the build. If there is any ambiguity and it can be cleared up, then it should be.

 

[Andy Bettencourt]

Originally posted by Joe Harlan@Nov 19 2005, 05:06 PM
Just a thought here. All else being the same. .040 is worth .1 compression points on a L24 Datsun over .020..

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Can't I max out my .5 point increase when I *true* the head under ITCS D.1.l?

I don't think I should be giving away anything other than the displacement right?

AB

 

[Joe Harlan]

Originally posted by Andy Bettencourt@Nov 19 2005, 04:25 PM
Can't I max out my .5 point increase when I *true* the head under ITCS D.1.l?

I don't think I should be giving away anything other than the displacement right?

AB

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Andy I have not CC'ed a Miata head so I cant tell you the combustion chamber shape and how much you would need to take off to get to the max compression. Be sure to optimize your deck height before cutting the head. I also am not sure that the total displacement will out do the extra weight of the piston.

Andy sorry If I am confused but I think your doing an 1800 miata?

1839 stock displacement
1861 .020 displacement
1884 .040 displacement

23cc less displacement.............will it matter at 8000 rpm?

 

[ITANorm]

Originally posted by Banzai240@Nov 17 2005, 11:26 AM
Again, that's BS!  A wire is a wire... a resistor is a resistor...

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So, if I just happen to use a piece of nichrome WIRE as a "professional" replacement for the connection between my coolant temp sensor and my ECU, that's acceptable, right??

 

[ITANorm]

Originally posted by Joe Harlan@Nov 19 2005, 05:06 PM
Just a thought here. All else being the same. .040 is worth .1 compression points on a L24 Datsun over .020..

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Which is why "OEM" OS pistons have slightly more dish than stock pistons - therefore the "dome / dish" doesn't not EXACTLY meet stock spec - which means that even the manufacturers' replacement OS pistons are illegal, by the strictest interpretation. The tops of most OEM-supplied OS pistons DO NOT exactly match the factory-installed ones, and there is more difference in the 1mm OS than there is in the .50mm OS.

 

[Joe Harlan]

Originally posted by ITANorm@Nov 21 2005, 09:58 AM
Which is why "OEM" OS pistons have slightly more dish than stock pistons - therefore the "dome / dish" doesn't not EXACTLY meet stock spec - which means that even the manufacturers' replacement OS pistons are illegal, by the strictest interpretation.  The tops of most OEM-supplied OS pistons DO NOT exactly match the factory-installed ones, and there is more difference in the 1mm OS than there is in the .50mm OS.

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I disagree. If the OEM replacement is the proper factory manual part number and tolerance it is completely legal. Some OE's decreased dome size or increased dish size to correct compression as part of a rebuild. Remember same late cars run pretty close to the edge as far as fuel goes.

 

[Andy Bettencourt]

Originally posted by ITANorm@Nov 21 2005, 11:58 AM
Which is why "OEM" OS pistons have slightly more dish than stock pistons - therefore the "dome / dish" doesn't not EXACTLY meet stock spec - which means that even the manufacturers' replacement OS pistons are illegal, by the strictest interpretation.  The tops of most OEM-supplied OS pistons DO NOT exactly match the factory-installed ones, and there is more difference in the 1mm OS than there is in the .50mm OS.

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I disagree. It says specifically that factory overbore pistons may be used...or THEIR exact replacements...not that the FOB pistons have to be exact duplicates of the originals.

I think we should clean up the rule. It should allow an overbore up-to .040 using FRP or their exact equivilants. When a FPR is not available in the size you want, you may have one made - but the stipulation then becomes it can't be any lighter than the factory-standard-sized unit - as well as being exact in every other way...

This cleans up the thought process out there that 'if there is no spec to design too, I can do what I want' - eliminating lightweight pistons from even entering someones 'creative' mind.

Right now, original intent or not, I don't see how anything but FRP or there exact equivilants can be used. If we want to match the rule to what some perceive as the intent, we can...but we will need some support.

AB

 

[Greg Amy]

If you guys wanna play word games, chew on this:

The rule states "Factory oversize replacement pistons (FORP) or their exact equivalent shall be used." Your position seems to be that if the factory did not offer +0.040"/1mm oversize pistons for your car, you cannot use them.

However, since we're getting down to the nitty-gritty of the words, remember that our rules are 'if it doesn't say you can, you cannot'. Also note that once a modification is allowed, 'if it doesn't say you cannot, you (bloody well) can.'** Finally, since FORPs are allowed and the rules state specific minimum requirements for these pistons, where does the rule state that these factory oversize pistons have to be from the same market/car?

Example: I want to overhaul an Acura Integra engine, but the factory seems to only provide 1/2mm overbore pistons. Or does it? For that exact same engine as used in Japan (same engine code, let's say) - but in the JDM Civic - Honda supplies both 1/2mm and 1mm overbore pistons. Therefore, I can use these pistons legally in IT, because:

1) They are (less than) +0.040" overbore,
2) They are supplied by "the factory".
3) They meet all the subsequent criteria.

Bottom line, oversize pistons - or their exact equivalents - are allowed if supplied by the factory and meet the subsequent criteria ("...shall provide the same dome/dish/valve relief configuration..., etc). Further, I can legally make aftermarket equivalents to those pistons as well. Therefore, these JDM pistons are totally legal on the Honda.

Hell if you REALLY want to play the wordsmith games, where does it even indicate these pistons have to even come from the same engine? All they have to be in order to be legal is "factory oversize replacement pistons or their exact equivalent..." Given that truck-sized loophole, why can't I use super-trick pistons from the Honda NSX?

Oh, I can see it now: the response of "That's Bullshit!" Yeah, well, prove me wrong. Remember what I wrote earlier, folks: playing these silly word games works both ways, and you may have just opened up a hole that someone will drive a toter home through... - GA


**Quoting a great IT.com philosopher...

 

[Bill Miller]

All they have to be in order to be legal is "factory oversize replacement pistons or their exact equivalent..." Given that truck-sized loophole, why can't I use super-trick and super-lightweight oversize pistons from the Honda NSX?

Greg,

Because that's where you cross the line of 'strained and tortured' interpretation.

 

[Greg Amy]

Oh? And how does one prove this? Are you going to protest someone for GCR 1.2.4 because they "tortured" the interpretation of the rules, while trying to also tell the scrutineer that this particular car cannot overbore +0.040" like the others in its class? Can you really say that with a straight face, given the discussions in this thread, not to mention other allowed mods that are "acceptable" (e.g., spherical suspension bushings, MoTec, etc)?

GCR 1.2.4 reads, in part, "The GCR shall not be given a strained or tortured interpretation and shall be applied in a logical manner, keeping in mind that it cannot specifically cover all possible situations." "Strained and tortured", my friends, is a red herring and completely unenforeable and has, historically, been ignored. It is the 'last bastion' of a debator with no logical standing.

Best of luck if you try a protest on it.

Your appeal is not well founded, and your thread returned to you. Next? - GA

 

[Joe Harlan]

Originally posted by GregAmy@Nov 21 2005, 11:30 AM
Oh? And how does one prove this? Are you going to protest someone for GCR 1.2.4 because they "tortured" the interpretation of the rules, while trying to also tell the scrutineer that this particular car cannot overbore +0.040" like the others in its class? Can you really say that with a straight face, given the discussions in this thread, not to mention other allowed mods that are "acceptable" (e.g., spherical suspension bushings, MoTec, etc)?

GCR 1.2.4 reads, in part, "The GCR shall not be given a strained or tortured interpretation and shall be applied in a logical manner, keeping in mind that it cannot specifically cover all possible situations." "Strained and tortured", my friends, is a red herring and completely unenforeable and has, historically, been ignored. It is the 'last bastion' of a debator with no logical standing.

Best of luck if you try a protest on it.

Your appeal is not well founded, and your thread returned to you. Next? - GA

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All they have to be in order to be legal is "factory oversize replacement pistons or their exact equivalent..." Given that truck-sized loophole, why can't I use super-trick pistons from the Honda NSX?

Um I think we are forgetting the factory manual requirement.