141 replies to this topic

[Keith Novak]

Keith, I'd be curious what you make of this? I have some metallurgy bona fides from another life, but I don't know how grinding/polishing might affect such a thin piece as these, especially since we're not sure how Mazda is processing them.

I don't want to ruin any of the improved springs just to figure out if grinding/polishing would affect them.

http://youtu.be/ZnY7hejSYIE

http://youtu.be/mgauNM7VZLM

Grinding often ruins whatever temper is left in the metal. It gets the metal too hot and cools uncontrolled so you get even worse residual stress left in the metal and makes it brittle. Not what you want in a spring. Heat treating or artificial aging is done slowly controlling the temp changes. Also when grinding it's easy to take metal off where you want to keep it for strength. There's not a lot of metal there to begin with. The tighter the corner the higher the stress concentration so if the grinding squared the inside of that corner off at all, it could make the bending stresses much higher at that point.

Polishing can be beneficial. The surface finish of parts will affect the fatigue life. Cracking likes to start at surface imperfections. Calculations for fatigue take the surface quality into account (accurate ones at least). The rougher the surface, the greater the knock-down factor on how a perfect part would behave. But if they hosed the part during grinding, there's that old saying, "You can't polish a turd."

[Maniac motorsports12]

So where do you get the beafier springs?

[Jim Drago]

He has them made

[SaulSpeedwell]

So where do you get the beafier springs?

He has them made

Yes, they are being made in low volume by real people with real beerbellies and real kids and real medical insurance right here in the U.S. Thus, unfortunately, they are somewhat expensive compared to what Mazda's worldwide purchasing power can achieve.

You can email me at miataboxes>>>AT<<<gmail.com if you want some springs.

And - I don't think I am talking out of school here, but a few builders (including ESA/Drago) can put these same springs in your trans as well, although you may need to ask for them specifically.

If this post is out of line somehow, the Mods can zap it - in which case I can send the poster the same info by PM, I guess?

[Michael Novak]

This is the kind of part(s) that should be approved quickly. It is not a performance gain--it is something that keeps costs down overtime by transmissions not breaking.

[KW78]

I know most active posters here have a ton of experience with rules or SM issues in general and working thru them. But, I think FWIW this topic I think reveals some important issues.

I for one, think it is legal to run and alternate spring from the fastener rule. This spring locates something (a sychro key) and keeps an assembly working. Just because it doesn't perform this function thru a clamping load, like a nut and bolt, doesn't kick it out of the fastener category. Is a cotter pin a fastener? Is the circlip that holds a rear wheel bearing in a fastener, or the spring clip on the CV axle? I don't think it is a "tortured interpretation" to say these are fasteners.

This is the kind of part(s) that should be approved quickly. It is not a performance gain--it is something that keeps costs down overtime by transmissions not breaking.

Be careful what you wish for, and what kind of precedent it sets! Our race cars have mechanical limits. Increasing those limits is in fact, a performance gain. Sure a reliability enhancement is OK when used at the same performance level, but the competition reality is that if something lets you shift faster, then you're going to shift faster.

This concept of "it's for reliability, and not a performance gain" single handedly destroyed the American Sedan class in a short 3 years. As applied to the transmissions, it seriously progressed from doing something about transmissions not holding up (which started with missed shift from syncro problems) to where a high $ dog box is allowed, because they are indestructible and are a "cost savings" that way.

Food for thought.
Kyle
(former AS junkie with 3 gathering dust, now Miata Junkie w 4 turning laps)

[wheel]

While I agree with Kyle, in that the clip could be considered a fastener, I disagree about his characterization of the reliability issue ruining ASedan. In fact, ASedan has moved from a high of 18th in participation to a solid 10th overall in 2012, mainly because the old "eight starters, four finishers and four smoking holes" is no longer the norm in ASedan.
wheel

p.s. As far as I can tell, of the 25 cars in ASedan at the Runoffs, one car had a dog box, and it was a used transmission that cost less than the former allowed transmissions.

[Mike Collins]

This is the kind of part(s) that should be approved quickly. It is not a performance gain--it is something that keeps costs down overtime by transmissions not breaking.

Approve what?

A spring that when I hold two in my hand I cannot tell the difference? Even if "I" could tell the difference do you think 3 AARP members with coke bottle glasses could?

[Bench Racer]

Even if "I" could tell the difference do you think 3 AARP members with coke bottle glasses could?

COLD Big Cheese, very COLD.

[wheel]

Mike,
Well, there is that. ;-)

wheel

[Jim Drago]

Approve what?

A spring that when I hold two in my hand I cannot tell the difference? Even if "I" could tell the difference do you think 3 AARP members with coke bottle glasses could?

I agree with what Mike is saying, If the spring looks and measures the same, it would be impossible to declare non compliant as there is no spec on the strength of the locating tang. Furthermore if and when a transmission is inspected for compliance I doubt very seriously that the tech inspector would be looking at the springs. They would be looking for coatings, gear ratio changes, lightened gears, straight cut gears etc.

[FTodaro]

I agree with what Mike is saying, If the spring looks and measures the same, it would be impossible to declare non compliant as there is no spec on the strength of the locating tang. Furthermore if and when a transmission is inspected for compliance I doubt very seriously that the tech inspector would be looking at the springs. They would be looking for coatings, gear ratio changes, lightened gears, straight cut gears etc.

I would say true to all that jim. I know how I felt at the nats when I had to pull parts off my car. To get to the point you could look at all 6 springs, we are talking about 8 hrs of work and special tools.

Going back to the original issue, Mark and others have commented, anticdotally it sppears that the current replacement springs appeare defective, they will snap with a few missed shifts. I will reuse an old proven spring before I would use new, so maybe we are back to what the spring should be.

[SaulSpeedwell]

... anticdotally it sppears that the current replacement springs appeare defective, they will snap with a few missed shifts. I will reuse an old proven spring before I would use new, so maybe we are back to what the spring should be.

Here is the transmission that started the whole saga - snapped springs on both 3rd and 4th gear after 3 hours of track time.

More of my usual boring droning, but the 2nd video addresses a conversation Drago and I had about whether it is possible to hurt the springs when pushing the bellhousing back on (Answer: No - but if anyone thinks we're missing something, chime in!).

http://www.youtube.com/watch?v=ZLSDCQx7FAc

http://www.youtube.com/watch?v=5xWpUzFnESA

[FTodaro]

I agree with you statement that its not the process of reassembly of the box. That leaves a spring with excess stress to start with. Same thing happened to me last year, new springs 4 races.

[SaulSpeedwell]

Another Miata Transmission Mystery Science Insomnia Theater production, this one focused on shifter issues.  More can and will be said about shifters, but by all means, check those shift bushings early and often!

 

http://youtu.be/znY7kJ6SK40

[FTodaro]

Nice Mark when can we see the IMAX version.

[Michael Novak]

Mark,

 

What are your thoughts on the alum. version of the shifter bushing?

[Jim Drago]

Mark,

 

What are your thoughts on the alum. version of the shifter bushing?

Not sure what Mark prefers. I prefer the nylon one, I just keep up with it. The trans shifts smoother with the nylon bushing IMO. The aluminum will stay consistent and never really need to be replaced. I just put a new nylon bushing in every three or four weekends. They don't look bad at first glance, but if you look close they develop a ring around them. Just buy 4-5 and change as needed or when you confidence is shot after missing a 2-3 shift that cost you three spots

[JRHille]

Thanks mark very helpful posts and videos.

[SaulSpeedwell]

Not sure what Mark prefers. I prefer the nylon one, I just keep up with it. The trans shifts smoother with the nylon bushing IMO. The aluminum will stay consistent and never really need to be replaced. I just put a new nylon bushing in every three or four weekends. They don't look bad at first glance, but if you look close they develop a ring around them. Just buy 4-5 and change as needed or when you confidence is shot after missing a 2-3 shift that cost you three spots

 

Totally agree.  The nylon feels better, just inspect and change semi-frequently, depending on how abusive you are.  I can't think of any time I would use the aluminum unit ... MAYBE a 24 hour race . . . but if I'm worried about the drivers destroying the nylon bushing in 24 hours, then the car ain't gonna make it 24 hours anyway

 

When I get a chance, I'll post some more ultra-boring videos regarding shifter issues.