Polishing transmission gears

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Polishing transmission gears

Postby brian » September 28th, 2015, 2:35 pm

As always, there were a lot of conversations about rules and cars at the runoffs. One of these conversations concerned polishing or REM treatment of transmissions gears and components. The GCR clearly states that only permitted modifications can be performed on components.

9.1.1.6F says, "Allowed modifications:Installation of any standard VW gear set which can be fitted without modification of any component of the transmission or of the gear set itself and the transposing of the ring gear to provide proper axle rotation. Permanent attachment of the synchro sleeve to 3rd and 4th gears is permitted."

When the REM tumbling/polishing process first came out, Bob Lybarger and I discussed the issue and decided that since it removed material during the process, and was not expressly permitted by the GCR, it was illegal. Vees have been disqualified for polished gears in the past and would be still considered illegal regardless of the procedure used.

I strongly advise those considering the REM process to think twice. You'll be exposed to protest and not likely to prevail.
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.
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Re: Polishing transmission gears

Postby hardingfv32 » September 29th, 2015, 11:34 am

Explain to me how removal of material on the gear 'wear surfaces' during a polishing process is any different than normal wear? I am assuming no material removal from non wear surfaces. How is Tech going to discern the difference?

What is the point of polishing if there is normally no metal to metal contact between the gears?

Brian
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Re: Polishing transmission gears

Postby brian » September 29th, 2015, 1:35 pm

The biggest philosophical difference is that normal wear is not an intentional effort to change performance. The difference is very visible since wear appears on the contact surfaces and polishing shows up by rounding of corners normally not struck by contact. After using tumbling processes like REM, the entire component is polished to a high gloss, almost chrome, finish including non contact surfaces.

As an inspector, a glance into the fill hole would be very informative.
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.
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Re: Polishing transmission gears

Postby hardingfv32 » September 29th, 2015, 2:43 pm

brian wrote:The biggest philosophical difference is that normal wear is not an intentional effort to change performance.


So you do not make a intentional effort to use a well warn transmission in an effort to change performance? FV has been using excessively warn parts intentionally to increase performance from day one. This argument does not hold water.

Back to a more fundamental question: What value is there in polishing the gears if they normally do not make physical contact?

Brian
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Re: Polishing transmission gears

Postby brian » September 29th, 2015, 7:11 pm

Why do I feel I'm running down a rabbit hole chasing esoterica?

Other than syncros, which can cause drag when new, I try to use the best parts available. Normal wear can increase drag since the finish caused by wear can be quite irregular. Worn out parts not only don't aid performance, they often create other issues like popping out of gear. Excessive clearances in assembly also come with negative issues. Excessive clearance between gears causes the gears to repel each other in a what's called walking. Rather than stay in a correct relationship with one another, gears with excessive clearance tend to move apart more and actually cause more drag.

Gears, like engine bearings move on oil film and stock gears have a finish that promotes oil film. REM treatments are more often found in high stress transmissions that have challenges maintaining oil film. It's used reduces friction and heat and improve the overall finish and durability of lessor quality parts.
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.
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Re: Polishing transmission gears

Postby willwin2day » October 3rd, 2015, 8:19 am

Brian:

With your reference to, "9.1.1.6F says, "Allowed modifications:" there is nothing more to be said and no argument to promote this illegal modification. Of course as the history of this class will prove, we will hear that everyone is doing it and they will have to go to great expense to make their transmissions right....so they will change our rules allowing the modifications. An example was many years ago when a builder was caught radising the top part of the carb (illegal at the time). So what did we do? We changed the rules. In short, no where in our rules can an argument be made for this modification. Period

Donnie Isley
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Re: Polishing transmission gears

Postby hardingfv32 » October 3rd, 2015, 1:26 pm

willwin2day wrote:With your reference to, "9.1.1.6F says, "Allowed modifications:" there is nothing more to be said and no argument to promote this illegal modification.


Worn gear mating surfaces are smoother than new gear surfaces. Is there a legal limit to how smooth a gear mating surface can get.... NO. So how does Tech make a judgement that the gear mating surfaces have been polished? They can not. The practical outcome of this that there is no way to prevent the polishing of the gear mating surfaces.

As far back as 4-5 years ago VSR was offering a $500 gear polishing option with their transmission rebuilds. Seems like this boat has sailed.

It requires a lot of time and effort to polish just the gear mating surfaces. Those with the money will get it done and they will pass tech. Might it be wiser to just allow the REM process at a net lower cost?

The carb change discussed above was an example of this type of approach. Without any modifications some carb tops are better than others... so you were forced to screen parts. With the simple mod that was approved ALL carb tops can be made to perform equally as well. For those of you new to FV this type of strategy is the basis for many of our rules. Allow modification to provide all parts with 'the chance' to perform equally.

Brian
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Re: Polishing transmission gears

Postby willwin2day » October 3rd, 2015, 6:55 pm

Brian....

With regard to your argument about the carb top...that is bullshit. People were radiusing...removing the edge of the carb top. Illegal. Sorry i got off the topic of this thread.

So...you have a gear in your hand and the entire gear looks like chrome including the sides? It has been illegally modified. Here you go....others are doing it so it must be legal. Your argument is not valid.
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Re: Polishing transmission gears

Postby hardingfv32 » October 3rd, 2015, 9:45 pm

1) I never said the the carb modification was legal before the rule change. What I did say was that a simple radius makes all carb tops equal. That is why the rule was changed.

2) I am talking about gear polishing... AND I specifically stated polishing the gear mating surfaces only. Not restricting the conversation to the REM process. Obviously you are not aware of advanced polishing processes that can be accurately targeted. I never stated that anyone is specifically using the REM OR using an illegal polishing technique.

I am sorry that my posts are too hard for you to comprehend but they are as clear as I can make them. My position is valid as stated.

Brian
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