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Thread: 2014 SCCA Runoffs

  1. #81
    http://www.trackhq.com/Banners/yellowsitesponsor.gif emilio700's Avatar
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    If the blend exists outside of the cylindrically defined work space, then it is not a gray area in my view. It's still not clear to me whether it was or not.
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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by emilio700 View Post
    If the blend exists outside of the cylindrically defined work space, then it is not a gray area in my view. It's still not clear to me whether it was or not.
    I don't think it's outside the cylinder, I think it's one of the edges of the cylinder. Possibly as little as just taking the sharp edge off so that it couldn't cut a finger or dump a sliver into the chamber.

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    Administrator ucfbrett's Avatar
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    The thing is, that blending at the bottom of the plunge cut is more important on the exhaust side rather than on the intake side. If the noncompliant engines were DQ'd because of the intake valves, that's even more disappointing.

  4. #84
    Sir flink
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    What is this "core shift" which the machining is correcting and why is it permitted? A reliability thing?

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by flink View Post
    What is this "core shift" which the machining is correcting and why is it permitted? A reliability thing?
    As I understand it, the head is made by pouring liquid aluminum into a mold. The mold has some things called cores that are stuck into it so the casting has cavities where you want your ports to go. These cores aren't held in place well and can shift so you can end up with some of your valve throats a little off from where they should be located. I think the plunge cut attempts to make sure the air can move easily past the valve when the valve opens. I could be wrong on the last point.

    I suspect plunge cuts might help equalize a good flowing OEM head and a bad flowing OEM head, but I'm just guessing now.

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    dirty smack talker hakeem's Avatar
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    Quote Originally Posted by robburgoon View Post
    As I understand it, the head is made by pouring liquid aluminum into a mold. The mold has some things called cores that are stuck into it so the casting has cavities where you want your ports to go. These cores aren't held in place well and can shift so you can end up with some of your valve throats a little off from where they should be located. I think the plunge cut attempts to make sure the air can move easily past the valve when the valve opens. I could be wrong on the last point.

    I suspect plunge cuts might help equalize a good flowing OEM head and a bad flowing OEM head, but I'm just guessing now.
    From my couple of days of reading, this is exactly the intention of the rule. To allow the various poor tolerances and casting issues to be equalized by machining the throat. Clearly some builders took extra liberties here and decided they could "smooth" the machining into the STR at the same time.

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    Senior Member albertg's Avatar
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    imho, I think the protest was a good idea. As I understand it, the pac west guys have been mentioning this exploit for months, correct? Someone told them to put their money where their mouths are and they did. That is why the process is in place.

    The unfortunate thing is that I don't think anything meaningful will come out of it. I think Drago posted something saying that next year's rules will likely have all those non compliant heads (due to plunge cut deburring) be compliant. If that is the case, nothing has really changed. The class is still too expensive and mod/hp creep is a problem. I wish they would implement some form of dyno/hp cap/claiming/sealed motor system, or a combination of those.

    Also, does anybody know the reason why the cal club sm guys were not well represented at the runoffs?
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  8. #88
    RaceTape Ninja Force McCocken's Avatar
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    Sand casting is essentially compressed sand molded in a form to control where you want, or don't want, the liquid metal to go. These sand cores are easily knocked out of the molded parts after the metal has hardened, then the sand is reused to make more molds. It's pretty cool to see in person. Old technology, but still effective. I have seen pictures from the industrial age where giant wheels were cast from holes literally dug in the ground. Die casting is a metal mold, instead of sand. the easiest way to tell is the surface; if it's rough, it's sand cast, if it's smooth, generally die cast. There are other molding substances used besides sand, too. Wax, for instance, for investment molding.
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    Senior Member granth's Avatar
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    Co Owner of Weekend-Racer John Mueller's Avatar
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    I'm headed to Topeka tomorrow to go see these heads at SCCA's HQ with Mazda. Should be fun.
    --------------------
    Thanks,
    John
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    #13 House Garage-built & Prepped Mid-Pack 1.6 SM / PTE / E3 Miata

  11. #91
    Senior Member fatbillybob's Avatar
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    Wow! This is a bigger scandal than when coughlin stole secrets from Ferrari F1. Who's head will roll?

  12. #92
    Senior Member robburgoon's Avatar
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    Interesting:

    "Plung Cut history as I remember it.

    Back in the day, if you read the 1600 manual well, you found quite a few things that were allowed and some of these things were used by SS shops to make more power. Perhaps the source of Steve S's frustration. I will say that I did write the SCCA and asked them to right a better rules package or people like me would find an unfair advantage. The ignored me and the rest is history. So, I found out that the 1600s heads suffered horribly from casting irregularities. The ports were irregular and did not flow alike and the combustion chambers were all over the place in terms of displacement, The manual, however, gave me a way to fix this since at the time I was led to believe that removing the valve seats was a no-no. I wrote a speadsheet and figured out how much to remove from each CC to get them matches (my Newen could easily cut the seats to tolerances less than 0.001") and then used the manual's suggestion to add shims under the valve springs to get the pressure back up to OE levels. This was considered cheating by some. I also did the same to the 99 heads (which don't come with a comprehensive manual) using the same logic. That lead to a DQ and subsequent overrule at appeal at Topeka and perhaps added to the problems I had with Jim (just to give you newer guys a bit of history).

    So, Jim saw to it that the shims would no longer be allowed and I had to get creative and go the new valve seat route which actually helped HP numbers and more importantly...........
    REQUIRED THAT I PLUNGE CUT a transition between the slightly smaller diameter seats and the ports. To do this I designed a cutting tool to fit my Newen. It was designed to roughly match the plunge cut that was made at the factory "so nobody would know" shhhhhhh!!!!!! I also went a bit deeper than the OE cut, again using the NEWEN to get all of the depths the same. I then bead blasted the head (BEFORE I cut the seats) to take away the shiny new cut and bingo, ultimately better matched flow and I could stand the valves up and get my spring pressure back without the shims. That was my effective FU and thanks for forcing me to make our motors even faster. I'm still not sure that the stiffer (effectively) valve springs are the way to go, but with good HLAs, floating the valves might open the lifters and cause the torque to suffer. It might be a good idea on the bucket lifter motors though, but now I'm getting sidetracked.

    Looking back I SUSPECT the plunge cut rule came in because I was not the only one doing this and it was easy to sell the logic. Back to my tangents.....


    The problem you have with a curved tool, especially in a 1600 with more material to cut on the short side, is that you can make your flow worse. Not as much the case on the NBs (just look at the pictures that have been posted . In order to overcome this, you need to manually go in and straighten the "backward" curve on the short side, or as some have done, to my horror, use a straight cutter and screw up the looks of the long side. You can manually fix the short side with a small round file and as you pass tech a few times you will blend more and more, leaving just enough to feel the edge."

  13. #93
    Senior Member fatbillybob's Avatar
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    Rob,

    I find the story very interesting having built many engines despite not being an SM guy. Is there a thread somewhere with pictures that explains all the controversy?

  14. #94
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by fatbillybob View Post
    Rob,

    I find the story very interesting having built many engines despite not being an SM guy. Is there a thread somewhere with pictures that explains all the controversy?

    That story I posted isn't all that recent, it goes much further back. Go visit mazdaracers.com. There's several threads about runoffs and rule changes.

  15. #95
    Senior Member robburgoon's Avatar
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    "Ron,



    It's really easy and frankly simple to get by tech if you have no problem playing that way. I prefer the make it legal approach. Give this some thought and bounce it around with your guys and see if you can get it through.



    The top radiator tube goes to the head where the thermostat is also located. A sensor is in the top of that housing with a one wire connector going to it. Pull that out and the ECU will not be able to use that signal to retard the timing. You can play with it on the dyno if you like. Pull the wire and connect it to a good ground point and you can tell all of us how much HP was lost.



    The 1600 used to make the most power when the water temp reached 195F but before the intake was heat soaked. As I recall the power was still there at 215F (with the sensor disconnected), but it has been a while.



    Here is something else to consider that has been discussed before. Oil coolers and or modified HLAs or solid lifters for the NAs.



    An oil cooler would have the most impact on the 1600 and NA 1800 since they use HLAs rather than the shimmed lifters in the NBs. I had a little trick for that too. Clearly cheating but when I developed it, I did not know that Mazda was reselling SBI HLAs (or SBI and Mazda got them from the same place), and, cheap as I am, I did not want to pay $15 for a new lifter. SBI sold them for about $5.



    If you take the lifter apart and remove the little ball and spring and the oil, you can collapse the lifter. Re-install it and measure the gap between the base circle of the cam and the top of the lifter. I had little shims made that i installed in the plunger which allowed me to set the gap the same way as you would on the NB motors. Leaving the spring out kept the lifter from pumping up and holding the valve open IF there was valve float. Clearly in violation of the rules, but it was a really inexpensive way to take the HLAs out of the NA v NB equalization equation. We did ask for solid lifters in the NAs but didn't get it. No idea if they are now allowed. If not, it's one way to reduce 1600 costs and improve NA power drop off. If you hear lifter clatter after a session you probably also noticed a power degradation.



    Think cheap and effective and you should get enough on board to get it through. If you run into resistance, question the reason(s) and don't settle for "thank you for your input"



    Jim has already suggested closer to ITA rules for the 1600, so your chances are much better now than they were ten years ago. Cheap and effective. "

  16. #96
    Senior Member robburgoon's Avatar
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    "TO: Spec Miata Participants

    FR: SCCA, NASA, Mazda Motorsports, and the Spec Miata Working Group

    RE: Class Intent, Direction and Regulations

    DT: November 14, 2014





    In the spirit of open communication, we wanted to update you with where we are at in the process layed out in last week's memo to the SM community. Additionally, we have been asked to share more details regarding what the working group of industry experts uncovered in Topeka, Kansas, where the non-compliant cylinder heads are stored, during the investigation into the illegally modified cylinder heads protested at the 2014 SCCA Runoffs; below we shed a little more light. Thank you to all of those who have spent the time sharing their thoughts with us.



    As a reminder:



    The Spec Miata (SM) class is intended to provide the membership with the opportunity to compete in low cost, production-based cars with limited modifications, suitable for racing competition.



    The rules are intentionally designed to be more open than the Showroom Stock class but more restricted than the Improved Touring class.



    The working group that visited Topeka discovered that there was a variance in the amount of smoothing, blending and porting of the sharp edge from the plunge cut among the illegal heads; some were egregious - a clear violation of the rules in an attempt to gain a competitive advantage. Others were less severe, but still a violation of the rule. Some have suggested that we should adjust the rule in order to allow for a certain level of blending and porting. In keeping with the intent and integrity of the class, NASA and the SCCA, with council from Mazda, determined that would not be the best course for the class. It would increase costs for the competitors who have not violated the rules and for the future entrants of the class; this is in direct contradiction of the spirit of this class, which we desire to keep costs manageable and to have a fair and level playing field.

    A challenge we are presented with is that there are competitors who have plunge cuts that had engine builders who de-burred and smoothed the sharp edge in their belief of practicing "good clean-up." This is inevitably an issue that the plunge cut provides, along with additional costs to perform, and to measure or tech. As a result, returning to stock cylinder heads is ultimately the goal and in alignment with the intent of this class. Many of those who have compliant cylinder heads, per the rule set, have asked a very fair question of why they may receive a weight adjustment. First, please know that if weight adjustments are given, this adjustment would not be punitive; the weight adjustments, if any, would be targeted to offset the advantage in horsepower of the plunge cut over a stock head - to equalize them. The benefits of the weight adjustment to the class would be as follows:

    It will allow all racers with currently compliant heads to continue to race those engines.



    It will encourage anyone building a new engine to use a stock head, rather than spend money on performance increases that would be neutralized with additional weight.



    It will also give racers who currently race with stock heads an equal chance against engines with legally performed plunge cut heads.

    Recognizing the number of modified cylinder heads in the community (both compliant and non-compliant), the expense to replace these and the potential parts availability concern, the working group agreed to have an independent, third party test and determine the effect of the individual and collective modifications; this process is underway. The testing group is currently gathering various cylinder heads and engines. The group will flow test heads first, then run all heads on the same engine, then do the same exercise again with another engine. The testing group will dyno various cylinder heads to determine what horsepower advantages the modifications have, ranging from those egregious to the compliant, compared to one another and to stock heads. These findings will be shared with SCCA, NASA, and Mazda and in turn be shared with the entire Spec Miata community.



    Using these data, the weight adjustments, if any, will be determined and outlined during the December 14 SCCA Board of Directors meeting, in conjunction with NASA's determination. NASA, SCCA, and Mazda are working together to help make the right decision for the good of the class - one where members will have the opportunity to compete in low-cost, production-based cars with limited modifications, suitable for racing competition.



    As always, we appreciate your support,



    Lisa Noble, SCCA President and CEO

    John Doonan, Mazda Motorsports Director

    John Mueller, NASA Spec Miata National Director

    Robert Clarke, SCCA Pro Racing President/SCCA VP of Business Development

    Tony Ave, SCCA Club Racing Board

    Steve Sanders, MAZDASPEED Motorsports Development Manager

    Mike Allen, MAZDASPEED Motorsports Development Specialist"








    "If you read between the lines, it would appear that SCCA is so pissed at what the SMAC and CRB has done over the years that they want to blow SM up and start over again"

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