brake temps -how hot is too hot?

[onegammyleg]

Discs are made from cast iron and this metal has a temperature limitation of about 1220F before it changes composition (structure).
Cast iron is used because it holds it shape and dimensions the best.
Discs are not made from steel.

Most suspected diesc warpage problems are not actually so.
In most case they end up being an uneven transferance of pad deposits that have transferred to the discs surface.

The high spots of depositied friction material and the disc in that spot keep getting hotter and hotter untill it bonds with the disc.(1200 to 1500F = cementite)

if you have just noticed the start of a vibration but the discs havent reached that high temperature the depsoits can be broken off the disc with garnet paper.(not sand or emery paper)

On a disc that has bad juddering it is often fixed with surface grinding , and while this does make it good for a short time it doesnt undo the changes that have occured in the disc metal itslef.

The localised hotspots are still there and will affect the evenness that he disc heats up and cools forever.

Its just a matter of time before this disc is juddering again.

If you have a juddering disc , throw it away.

[onegammyleg]

...and most fade is caused by the lubrcating effect of the gasses produced from the hot pad friction material and not from the disc being too hot.

[onegammyleg]

yeup

[Sigifrith]

How did the Moon eyes turn out?
Where they of any value?

[lindermant]

Originally Posted by Sigifrith

How did the Moon eyes turn out?
Where they of any value?

no measureable FE gain in the time I had them installed; they were very noisy at slow speeds so I took them off. I thought they looked cool, but that's about it

[cfg83]

lindermant -

I never had a problem with overheated brakes. The Saturn service guy warned me but I ignored him because I was never a "performance" driver that would push it to the limits.

And the moons were stunning regarding the looks. I had them powder-coated on my previous SC2 :

Attachment 625

However, they became my bane. On certain road bumps, the front passenger one would go flying off. I *think* this had something to do with my Saturn front wheel drive balancing, but I have no proof, only a similar story from a friend. I couldn't justify keeping them on.

If it weren't for that, I would have lived with the scratchy sounds. I did it to complement the looks of the car, not for saving gas.

CarloSW2

[cfg83]

theclencher -

Originally Posted by theclencher

There must be a way to attach them that eliminates the noises. Perhaps a gasket?

I tried electrical tape over the teeth, but that didn't work. A gasket would be better. Over time, I think the teeth would scrape through. The key would be finding a gasket made of the right material. Also, the teeth bend easy, so I think the cover can become loose after multiple on/offs.

I think the real deal would be to go with real racing disks that require 3 holes screwed into the rim.

Since my SW2 has fancy allows, I can't install the racing disks on them. However, I have recently been staring at the "aluminum wheel center caps" on my Saturn and wonder if a "donut" shaped disk that exploited the center caps as a locking base might work. Just a thought experiment, though.

CarloSW2

[lindermant]

Originally Posted by theclencher

Were the teeth the source of the noise, or some other part? I'm not familiar with the exact geometry of those disks, but I would think the teeth need a secure bite and the rest of it either needs enough clearance (wheels flex) or a gasket to isolate from metal to metal contact.

On my mooneyes brand discs, it was definitely the teeth causing the noise. They were a tight fit, but at least they never flew off

[cfg83]

theclencher -

Originally Posted by theclencher

Were the teeth the source of the noise, or some other part? I'm not familiar with the exact geometry of those disks, but I would think the teeth need a secure bite and the rest of it either needs enough clearance (wheels flex) or a gasket to isolate from metal to metal contact.

As lindermant said, it is definitely the teeth. I still have them, even the ruined ones that flew off (they mock me!!!!!!!!!!). I'll try to post a picture. I think they are proof that the steel rim is flexing.

CarloSW2

[cfg83]

theclencher -

Here's the pics of the moon disk :

Attachment 636

Attachment 637

Attachment 638

I think a gasket would be troublesome because, as you can see (with your mind), the gasket would be "pulled off" when you pushed the disk in. Also, I forgot that the teeth are little "double teeth", or maybe little grabby fingers.

CarloSW2