December minutes

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Dietmar
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December minutes

Post by Dietmar »

The FV Ad Hoc Committee met on December 3
Members attending: Steve Oseth, Stevan Davis, John Petillo, Barret Hendricks, Stephen Saslow, Bruce Livermore, Alex Bertolucci, Phil Holcomb, Dietmar Bauerle
Guest: Fred Clark

Steve Oseth will be attending the PRI show next week and discussing forged pistons with various vendors. His main focus of course will be cost, availability, and assuring that whatever end product is produced for FV will meet the current specs for pistons. One of the concerns the Committee has is with the distance between the top ring groove and the top of the piston. This area , if not controlled, could create a performance advantage

Aftermarket connecting rods. Information we have received is that the aftermarket rods have been approved.

The Committee once again discussed rear suspension, fairings and locating arms. After a considerable discussion, the Committee feels that, in the best interest of the class, we should modify the rules to ALLOW fairings between the axle and the locating arms. In order for this to happen, a section of the current GCR will/would have to be eliminated to meet current bodywork rules. Section “O” under heading C.9 reads: …the rear locating arm(s) coil springs, and shock absorbers shall not be faired in and shall be visible from the side without removal or manipulation of any part or panel.
A new rule will replace this archaic section and will be drafted and presented to the CRB with our recommendation .

No other items were presented or discussed.
Next meeting scheduled for Jan 3
hardingfv32-1
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Joined: December 1st, 2006, 8:01 pm

Re: December minutes

Post by hardingfv32-1 »

Dietmar wrote:The FV Ad Hoc Committee met on December 3

A new rule will replace this archaic section and will be drafted and presented to the CRB with our recommendation .
Does this mean that nothing will change for 2015? I assume the 2015 rule change period is coming to a close.

Brian
brian
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Joined: June 26th, 2006, 12:31 pm

Re: December minutes

Post by brian »

Unless there is an error or omission, or an emergency supply issue, the 2015 is cast in stone. The BOD voted on the final rules last week. There is a final Fastrac posted at SCCA.com
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
sharplikestump
Posts: 183
Joined: January 12th, 2009, 2:28 pm

Re: December minutes

Post by sharplikestump »

On the issue of having pistons made, I am hoping you realize that with the rules written as they currently are, pertaining to the maximum distance from pin centerline to the roof of the top ring groove, that if you allow a thinner ring, you are creating an unfair advantage. Because the only way that compression ring will seal is if any required spacers are placed ABOVE the ring (or you suffer terrible leakdown), therefore unless you are using stock rings, our rings are some distance below the roof. if you allow a narrower groove you effectively allow the ring to be placed higher w/o violating that distance. For this reason, I would suggest that IF any new pistons are allowed, you dictate that the top ring groove remain at 2.5mm. or you dictate that the roof be lowered to compensate for the raised ring. Another (and possibly simpler) means of maintaining this would be to establish a maximum dimension from the pin centerline to the top of the top ring instead of to the roof of the top groove. Not doing so instantly obsoletes all existing pistons.
Additionally, while a narrow groove is nice, it affords another advantage in that it effectively raises the compression ratio slightly by reducing the size of the void that exists between the spacers and the cyl. wall, as well as the area behind the compression ring.
BTW, While the Chinese pistons have a narrower ring groove, that groove is much lower on the piston, more-so than .5mm. eliminating any such advantage. It is also deeper than the groove on other pistons.
What happened to the 300 K/S pistons that were located and available to us?

Mike P.
hardingfv32-1
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Joined: December 1st, 2006, 8:01 pm

Re: December minutes

Post by hardingfv32-1 »

Replacement pistons made from forged blanks can be CNC machined to the exact same dimensions of the original VW piston. There are no cast blanks available for this purpose. This low volume custom piston process is based around proprietary shaped forged blanks.

The CNC programing allows for a 'no extra cost' option to change a dimension of the piston being machined. This would allow for piston OD's that could compensate for over size bores caused by wear and honing. No requirement to change the current bore spec. New K/S pistons will not accomplish this for you. Extending the life of used barrels is the main goal.

There is no need to change the dimensions of the ring grooves, just make the OD variable/open within the context of the current rules.

Brian
sharplikestump
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Joined: January 12th, 2009, 2:28 pm

Re: December minutes

Post by sharplikestump »

hardingfv32-1 wrote:Replacement pistons made from forged blanks can be CNC machined to the exact same dimensions of the original VW piston. There are no cast blanks available for this purpose. This low volume custom piston process is based around proprietary shaped forged blanks.

The CNC programing allows for a 'no extra cost' option to change a dimension of the piston being machined. This would allow for piston OD's that could compensate for over size bores caused by wear and honing. No requirement to change the current bore spec. New K/S pistons will not accomplish this for you. Extending the life of used barrels is the main goal.
IF this is truly the main goal, why not just knurl the pistons. It is entirely realistic to swell any existing pistons as much as we want with the existing bore limit.

There is no need to change the dimensions of the ring grooves, just make the OD variable/open within the context of the current rules.
Realistically, how long do you think it would be before the ring groove dim.s get changed? What does that do to all existing pistons?

Brian
Brian,
While I do like the idea of us not having to commit to a large production number, If this is allowed do you see an advantage to the forged piston having an advantage in the context of it being more thermally stable, affording it's being installed with tighter tolerances w/o the fear of seizing?
Additionally, if I understand it right, the forged unit is inherently stronger and more resistant to failure, allowing the builder to cut the crown thinner than with a cast piston, effectively raising the rings closer to the combustion chamber. Also, since I know of no spec pertaining to crown thickness, I see the possibility of a real problem here: produce a piston with a very thick crown, mill it extensively, and end up with a very high ring that complies with the rule. Of course, trimming the cylinder would still achieve the min. deck clearance.
Then there is the issue of weight. Even if a forged piston is produced to the same thickness, it has the weight advantage of not having steel supports cast into it.
As I would guess it is with many other builders, I have hundreds of cylinders that are well under the current max. diameter, many sets fully cleaned, prepped and matched, and while it appeals to me to put them back in service, I have strong reservations about allowing forged pistons. Besides the reasons I have stated (and there are others), in this case, I also fear the unknown, along with the almost inevitable "development creep". How much of an advantage would such a piston have to actually offer, and maybe even more importantly, how much perceived advantage would it take to injure entries.
In addition, even though I would love to use some of those sets of cylinders that are in storage, I personally opt for grabbing a new set off of the shelf, especially now that China has their latest ones out with 17 full fins and a very generous base, not to mention the best quality of any cylinder I have ever held. Part of my reasoning has to do with the fact that any rings that I have used seal better in the original dia. that they were designed for. Will be doing exactly that as soon as I finish this post.

Ditmar,
It was not that far back in time that you were calling to take orders for some of the (300) K/S pistons that were found. Can you give an update on them?

Bottom line......NOT looking for a fight. I just don't want to see us jump in to something that harms this great class, especially when it seems unnecessary.

Last question....I am wondering if this should actually be posted under the "tech questions" section. If so, will someone that is sharper than me please send it there? Thanks.
jpetillo
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Joined: August 26th, 2006, 2:54 pm

Re: December minutes

Post by jpetillo »

sharplikestump wrote: If this is allowed do you see an advantage to the forged piston having an advantage in the context of it being more thermally stable, affording it's being installed with tighter tolerances w/o the fear of seizing?
Mike, I believe that cast pistons are much more thermally stable than forged, unless things have changed in recent years.
Dietmar
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Re: December minutes

Post by Dietmar »

Mike:

Be assured that the Ad Hoc Committee will take into account all the "variables" that you have mentioned and probably more. We are not planning to simply recommend ANY forged piston without a lot of thought.

As for the K/S pistons... A brief history. The Committee worked on getting AA to come up with a cylinder that would be more appropriate for use in FV. We also asked that a piston be made by the same company that would have the same dimensions at a OEM piston- not what is currently being made by AA as a replacement ( with 2mm rings). The cylinders are available to anyone ( as far as I know) and I have been told that these very cylinders were available even before we approached AA and were being used in Europe and even found their way into some engine builder's inventory here in the US- unbeknownst to any member of the Committee.
In the meantime I was in contact with the rep for K/S and after some "searching" on his part, he was able to find 300 or more K/S pistons and gave us a price per unit. A couple of Committee members tried to organize a group of engine builders to purchase multiple units to keep the cost within reason considering that there would be shipping and duty to pay on each piece. We were unsuccessful in finding more than two people ( I was one) who wanted to buy into this multiple purchase, and so it fell by the wayside.
Given the exchange rate today, buying the remaining K/S inventory- or even a portion of it would be to our advantage, but we would have to find several interested parties willing to put up some rather large dollars.
Our next meeting should provide the Committee with more information on forged pistons .

Dietmar
sharplikestump
Posts: 183
Joined: January 12th, 2009, 2:28 pm

Re: December minutes

Post by sharplikestump »

Dietmar wrote:Mike:

Be assured that the Ad Hoc Committee will take into account all the "variables" that you have mentioned and probably more. We are not planning to simply recommend ANY forged piston without a lot of thought.

As for the K/S pistons... A brief history. The Committee worked on getting AA to come up with a cylinder that would be more appropriate for use in FV. We also asked that a piston be made by the same company that would have the same dimensions at a OEM piston- not what is currently being made by AA as a replacement ( with 2mm rings). The cylinders are available to anyone ( as far as I know) and I have been told that these very cylinders were available even before we approached AA and were being used in Europe and even found their way into some engine builder's inventory here in the US- unbeknownst to any member of the Committee.
In the meantime I was in contact with the rep for K/S and after some "searching" on his part, he was able to find 300 or more K/S pistons and gave us a price per unit. A couple of Committee members tried to organize a group of engine builders to purchase multiple units to keep the cost within reason considering that there would be shipping and duty to pay on each piece. We were unsuccessful in finding more than two people ( I was one) who wanted to buy into this multiple purchase, and so it fell by the wayside.
Given the exchange rate today, buying the remaining K/S inventory- or even a portion of it would be to our advantage, but we would have to find several interested parties willing to put up some rather large dollars.
Our next meeting should provide the Committee with more information on forged pistons .

Dietmar
Dietmar,
Thank you the assurance. Good to hear. Especially in light of the situation with the K/S pistons. As you know, I stated that I prefer the AA units, but if it turns out to be a close call on them, please call me. Does surprise me that with all the clamor on pistons, that there was such limited interest, but it is what it is. I plan on addressing the issue with my contact at AA, as I would be all for their piston with the wider grooves, (as they had when I first dealt with them) but I suspect that there would not be that much interest in them either. This forged piston agenda concerns me.
Thank you for all your effort.
Mike
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