Oversized Fit Pistons

[Art Smith]

Not everyone is as committed as you, or agree with your views.. I have an engine apart now that I hope will win big races and the Runoffs. My people advised against going to the 1/100" oversize pistons. We believe it is unnecessary in this application. To draw a parallel, despite your insistence that proper kent engines require electric water pumps pumping coolant through frost plug holes, how many kent racers out there are making those modifications? And how many are running 3-stage oil pumps with your sophisticated scavenging systems. Some people believe your mods will make several HP each, yet racers are not doing it. There is no reason to believe FF racers will spend money putting new pistons in perfectly good FIT engines, to perhaps make a fraction of a HP in the rpm range before the restrictor is restricting. Fortunately, the class has never been more about driving, and racecraft. Investment in the tracktime is most important, and honestly, much more expensive than insignificant engine repairs.

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hopefully with the name calling behind us, we can all get back to spirited discussion and debate of the "latest gift" from Topeka!
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parse it as you will, I stand by the ideas included in the post above. given the spirited name of the discussion, 100% agreement wasn't expected and I'm clearly not the only one "guilty" of posting minority views!! taxation without representation is wrong and completely unacceptable. it is a statement of fact and not political commentary that everyone running a Kent was forced to buy +0.005" pistons and have their engines rebuilt to keep up. performance creep, in any amount greater than zero, is not good for the class and in this case has the potential to be extremely divisive (ie: restrictor size). I was against the rule change to allow Kents +0.005" pistons to NO avail and I'm against the rule change to allow the alternate engine over size pistons; extremely bad policy in my opinion!! decision making not driven by structured process AND objectively verifiable data (ie: not opinions) is doomed to produce poor results in quantity!

your "parallels" are your parallels......................

Art
artesmith@earthlink.net

[problemchild]

it is a statement of fact and not political commentary that everyone running a Kent was forced to buy +0.005" pistons and have their engines rebuilt

This is absolutely NOT FACT!

No one was forced to do anything. It was an option, just as repairing FIT engines with oversize pistons is an option.

Whether it was good for the class or not, is an OPINION.

An example of a FACT, would be that SCCA made some FF racers remove side safety structures to reduce body width. Whether it was good for the class or not, is an OPINION.

My OPINION would be that, although minimal, any performance gain from the piston repair, will be much more than from the FFs with side safety structures. Also my OPINION, the non-optional side safety structure removal was a much more expensive process than the optional piston repair. Although not a fact, one could certainly opine that side safety structure removal was actually an expensive mandatory performance upgrade. Since the rule came into play, has anyone noticed Mygales getting slower or winning fewer races?

[John Nesbitt]

I am not sure that this is a fact/opinion split, as much as it is a fact/value calculation deal.

Full disclosure: My only interaction with Art Smith was a years-ago compliance review in which I was involved. I do not even remember the issue that he raised. I do remember thinking that he really knew his stuff and that he closely read the FF rules with an open, informed mind.

If Art said that x was the absolute best, no-compromises, spare-no-expense Kent spec, I would take that to the bank.

On the other hand each competitor has to decide for himself whether the performance gain from oversize pistons etc. is worth it to him.

[jharvey]

I guess if this thread reinforces anything, it's that people only like rule changes so long as they perceive it as a benefit to themselves.

I have a freshly built Loyning with 0.005" over pistons. I did not put them in for power, I put them in because I had to. I am a hack driver in an old car. Since some of the Honda people (engine builders, SCCA, whatever) are about helping people save money, then it only seems right to allow 0.010" over pistons for the Ford.

It also seems that SCCA does not really care about this forum anyways, so we all may feel better in venting, but it does not seem that any of it really matters.

Formula Vee seems like a well attended class. How many piston options do they have? I only see 1 bore size in the GCR's. I've heard rumors about how much a good Vee build can cost. Maybe the rules should be changed to save them money too?

[reidhazelton]

I guess if this thread reinforces anything, it's that people only like rule changes so long as they perceive it as a benefit to themselves.

Limiting rules creep through broken processes with no member input benefits everyone.

Like I said, I have nothing against the Honda. I'm against making it more expensive, and creating Zetec/MZR issues with what was a well written rules package. I've been trying to build a FF/Honda for years now, so as to a hp perspective, it would benefit me but the cost increase and creep is what I take issue with.

[John Nesbitt]

Limiting rules creep through broken processes with no member input benefits everyone.

Like I said, I have nothing against the Honda. I'm against making it more expensive, and creating Zetec/MZR issues with what was a well written rules package. I've been trying to build a FF/Honda for years now, so as to a hp perspective, it would benefit me but the cost increase and creep is what I take issue with.

It comes back to the opacity of the process around this rule change. What was the rationale? Why was there not time for comment?

It may be that having a repair option for Fit pistons is a cost-effective solution for worn engines, with minimal impact on performance. But who knows? And who drove the decision? It appears not the affected stakeholders.

[alangbaker]

it is a statement of fact and not political commentary that everyone running a Kent was forced to buy +0.005" pistons and have their engines rebuilt to keep up.

Sorry, Art, but that is not a statement of fact. It is a statement of belief.

Do you think that any racer would declare himself unable to keep up if he were told that his engine was down 0.3% on power?

Again:

I agree that the process followed to make this rule change happen was badly flawed, but I completely disagree that it in any way "forces" anyone who wants to be competitive to have their engine rebuilt. It's nonsense, pure and simple.

[Art Smith]

Sorry, Art, but that is not a statement of fact. It is a statement of belief.

Do you think that any racer would declare himself unable to keep up if he were told that his engine was down 0.3% on power?

Again:

I agree that the process followed to make this rule change happen was badly flawed, but I completely disagree that it in any way "forces" anyone who wants to be competitive to have their engine rebuilt. It's nonsense, pure and simple.

my data and the data I have access to suggests +0.005" forged pistons were/are worth 2-2.5 HPc (depending on the head) over standard size forged pistons all other things equal in a "National" quality Kent. ignoring my understanding of the facts, anyone interested in an objective and independent understanding of the facts just has to do a little home work. look-up when the +0.005" oversize pistons were approved. look-up how many engines at that year's RunOffs had oversized pistons. keeping in mind the best engines in the country at the time had new low time forged standard sized pistons, ask yourself if ALL of those RunOffs engine with oversize pistons suddenly developed a need to be overbored OR the competitors in consultation with a National Engine Builder felt compelled (ie: forced) to upgrade to keep up with the Jones. simple exercise and it's alleged the "truth will set you free"...........................

I doubt anyone knows what the oversized alternate engine pistons are worth and that's the point!! making decisions without data and without community input and without review leads to bad decisions. remember, the +0.005" pistons for the Kent were sold under very similar circumstances as a no performance upgrade to help competitors avoid the cost of sleeving old blocks..............

Art
artesmith@earthlink.net

[alangbaker]

my data and the data I have access to suggests +0.005" forged pistons were/are worth 2-2.5 HPc (depending on the head) over standard size forged pistons all other things equal in a "National" quality Kent. ignoring my understanding of the facts, anyone interested in an objective and independent understanding of the facts just has to do a little home work. look-up when the +0.005" oversize pistons were approved. look-up how many engines at that year's RunOffs had oversized pistons. keeping in mind the best engines in the country at the time had new low time forged standard sized pistons, ask yourself if ALL of those RunOffs engine with oversize pistons suddenly developed a need to be overbored OR the competitors in consultation with a National Engine Builder felt compelled (ie: forced) to upgrade to keep up with the Jones. simple exercise and it's alleged the "truth will set you free"...........................

I doubt anyone knows what the oversized alternate engine pistons are worth and that's the point!! making decisions without data and without community input and without review leads to bad decisions. remember, the +0.005" pistons for the Kent were sold under very similar circumstances as a no performance upgrade to help competitors avoid the cost of sleeving old blocks

Sorry, but there is a difference between FEELING you need to do something and actually needing to do something.

3.2/3.1995 = 1.0015649452, the area increases as the square of that, or 1.0031323395.

So would you care to explain how a 0.3% increase in displacement (proportional to the increase in area) would result in a 1.7%-2.6% increase in power?

[Art Smith]

Alan-

you'll arrive at the understanding you're looking for quicker working the problem backward from the dyno data; not from your assumption of the governing mechanism(s). I suggest you start your quest with a standard size forged piston in one hand and a +0.005" oversize forged piston in the other; assuming the only difference in their characteristics is OD is a mistake!! there's also more going on than meets the casual glance!! the dyno doesn't have political views so it's a safe place to start. as you discard your going in assumptions and begin to rely on objective measurements, things will get much clearer.......................

Art
artesmith@earthlink.net

[problemchild]

So would you care to explain how a 0.3% increase in displacement (proportional to the increase in area) would result in a 1.7%-2.6% increase in power?

We all choose to take input from different people, while weighing their expertise and their bias, and form our own conclusions and opinions. We also have to interpret data, depend on others to interpret data, both of which are very subjective. Should we assume, that according to this interpretation, if just upgrading an engine with a .005" increase in bore increased power 2.2%, that a .010" increase (more than double the area increase) would increase power 5%?

I could not accept that interpretation. I could certainly believe that a complete rebuild of an engine with worn out pistons and bores, with new pistons, rings, and properly clearanced bores, would yield a performance increase of 3-5%, regardless of whether the pistons were increased 1/200th of an inch in diameter, or not.

Certainly, a repair of a Honda engine, with new pistons, rings, and properly clearanced bores, will improve the performance of that engine before the repairs. That is the whole idea.

[LenFC11]

And still even those that agree there is some advantage say it's ok because it's not much..

0 is 0.. anything more then 0 is an advantage. No matter how small an advantage. So if a competitive racer wants an advantage they will seek out any rules allowing them to have an advantage.

To argue that it's ok be it's only a small percentage is rediculous.. in FF your never going to find huge advantages.. it's finding as many small advantages to add up to the best possible package

[problemchild]

And still even those that agree there is some advantage say it's ok because it's not much..

That is a very righteous attitude if you're not racing. If you were racing, and had an engine issue, perhaps you would prefer to buy $500 worth of parts, spend $200 at a machine shop, and repair your engine. Or maybe you would prefer to replace that engine. I have 7 engines in my shop and I know what my choice is. Many of us believe that small performance advantage is a very reasonable compromise so that our engines remain serviceable for many years if not decades. The very serious wealthy competitors among us, have many opportunities to outspend us. I am just fine with letting them max out their engine blocks for that perceived advantage.

[reidhazelton]

Many of us believe that small performance advantage is a very reasonable compromise so that our engines remain serviceable for many years if not decades.

How does an unsleevable block now last decades from this rule change?

[stonebridge20]

How does an unsleevable block now last decades from this rule change?

It gets .020 pistons in a couple of years.

[Daryl DeArman]

We all choose to take input from different people, while weighing their expertise and their bias, and form our own conclusions and opinions. We also have to interpret data, depend on others to interpret data, both of which are very subjective.

BINGO.

You can't get all the SRF engines within 2.5 HPc of each other, even when the intent is to build them identically.

A SRF3 on a dyno, with three consecutive pulls, all within 47 seconds of each other don't produce the same results. Results varied by .96 HP

[Daryl DeArman]

my data and the data I have access to suggests +0.005" forged pistons were/are worth 2-2.5 HPc (depending on the head) over standard size forged pistons all other things equal in a "National" quality Kent.

I don't doubt your data suggests that. I do doubt that all else was equal in those tests/engines. Either tuning changes needed to be made to achieve the same Lamda(therefore all else wasn't equal) or no tuning changes were made and Lambda was not the same. Clearly, those differences, whichever ones existed, were factors contributing to the HP difference. Same with the exhaust system design. The primary length, tubing ID, collector design and location was tuned for one displacement or the other. If the same system was utilized it also benefited one configuration more than the other, however little it may have been. All else is never equal.

look-up how many engines at that year's RunOffs had oversized pistons

How would we know this? What would it prove other than a certain number of folks determined it was worth the effort, regardless of whether or not it was.

[Daryl DeArman]

It gets .020 pistons in a couple of years.

JE p/n 325566 would be nice.