Spec Miata / Heads

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DickCDawg
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Joined: Fri Dec 05, 2003 11:42 am

Re: Spec Miata / Heads

Post by DickCDawg » Thu Oct 23, 2014 10:26 am

My understanding is that the top 6 'on track' finishers were called to impound for all races - so that if any of the 3 podium finishers were penalized there would be backups to take their place. In the case of the SM race, tech had decided to check several specific things on the top 6 in impound, but this list did not include removing valves from heads to check the protested plunge cut issue. I believe this first impound inspection was completed on Friday after the race, and all top 6 finishers passed. Tech then inspected the 9 protested cars, which took up a lot of Saturday. 8 of the 9 were found to violate the rule specified in the protest, and the 9th head was found to violate a of different rule section (relief cut near a one valve). An appeal was quickly turned in, and it took until late Sunday before the appeal was denied and all 9 protested cars were penalized.

FYI, here's a comment from SM'er Steve Scheifler who seems to have some detailed knowledge this issue, along with a link to photo's that illustrate the specific area in question (not of the penalized heads):

"As others have suggested, the degree of "blending" of the plunge cut edges in the protested heads varied from arguably nothing with no tool marks but "suspiciously smooth", to clearly visible tool marks and significant removed metal. The fact that some were so obvious only increased the scrutiny on the rest. And that's where there is still some debate. At least one machinist is adamant that even if it weren't routine to knock sharp edges off after cutting, the edge left from one cut to the next varies greatly depending on the shape of the casting at each port, the cutter, and just tolerances in the process. So a uniform sharp edge may not exist to begin with, and even routine cleaning can dull one. It is his contention that if his head failed then many heads would fail the "sharp edge feel test" even though they had not been intentionally altered and had no sign of tool marks. I have no evidence one way or the other but I think it needs to be investigated before rules are changed."

http://mazdaracers.com/topic/4783-writi ... 3-4/page-2

Dick

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integra55
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Re: Spec Miata / Heads

Post by integra55 » Thu Oct 23, 2014 11:54 am

ok … I understand about the top 6 being called to impound .. makes sense … I guess my question is … if the 7th place finisher had, in fact, been the 6th place finisher, would his car have had the head pulled, since he wasn't one of the ones originally protested ?

I realize he would have had to pass the areas that the inspectors had decided would be their points of emphasis .
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DickCDawg
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Re: Spec Miata / Heads

Post by DickCDawg » Fri Oct 24, 2014 5:31 pm

Yes, if Stearns had finished in 6th place instead of 7th, he would have been in impound for the tech's list of post race checks - for SM that list did include pulling the head and checking valve diameters & intake/exhaust ports, but did not include pulling valves from the heads which was required to check the issue in the protest.

Dick

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