[Shotimes] WTB rotors for brake upgrade

[Donald Mallinson]

I remember seeing somewhere a picture of rough cast rotors with holes, 
but they all have to be finish drilled, can't see that casting them that 
way would make a big difference.

The secret as I see it to drilled rotors lasting for street or 
competition is to chamfer the hole and make the holes smaller.

A set I had drilled (Caterpillar machinist did them on a break with 
drill bits I bought) for my MGB for street and autocross use, had 1/8" 
holes (don't need big holes except for visual effect) with much bigger 
chamfers on every hole.  A pattern was used to avoid the internal 
structure on the vented disks.  I used these disks for several years 
with ZERO problems.  It was a light car, with low HP, but it was driven 
hard, and the disks were pretty small so they probably got about the 
same abuse as bigger disks on a bigger, faster car.

The Chamfer relieves the stress that builds up around the opening that 
is what creates cracks in most drilled rotors.

Don Mallinson

Ian Fisher wrote:

>I've heard more than once that the drilled vs cast
>holes issue is a myth (ie, all rotors are drilled). I
>dunno the truth but I seem to recall that Todd Cook
>had something on his site asking for someone to prove
>that rotors were cast with holes. I think it was Todd.
>Either way, I just checked his site and couldn't find
>that segment. Don't have much time to poke around as I
>have a ton of parts to buy tonight. :(
>
>Ian
>
>--- Ron Porter <ronporter@prodigy.net> wrote:
>  
>
>>The Porsche rotors are made with the holes in them,
>>so they last longer than
>>the regular aftermarket drilled ones.
>>
>>At any rate, it is a "looks" thing for any car. If
>>you do track work,
>>grooved rotors actually have a benefit, and will
>>outlast drilled rotors. For
>>street use, holes or grooves are purely a "looks"
>>thing.
>>
>>Ron Porter
>>
>>-----Original Message-----
>>From: shotimes-admin@autox.team.net
>>[mailto:shotimes-admin@autox.team.net]
>>On Behalf Of Ian Fisher
>>Sent: Friday, April 15, 2005 3:39 PM
>>To: Paul L Fisher; 'Edward Mazurek'; 'SHOTimes'
>>Subject: RE: [Shotimes] WTB rotors for brake upgrade
>>
>>cross drilled rotors crack. Unless you plan on
>>replacing them often, I would not spend the money on
>>them. Porsche's come from the factory with them but
>>many PCA guys end up replacing the rotors a few
>>times
>>a season and/or switching to non drilled rotors.
>>
>>Ian
>>--- Paul L Fisher <sho@paul-fisher.com> wrote:
>>    
>>
>>>Why buy expensive rotors? Buy the cheap Chinese
>>>rotors from Autozone. They
>>>will last just as long.
>>>
>>>
>>>Paul L Fisher
>>>
>>>Visit my website: http://www.paul-fisher.com
>>>SHOClub Member: http://www.shoclub.com
>>>Amsoil dealer: http://www.paul-fisher.com/oil
>>>
>>>-----Original Message-----
>>>From: shotimes-admin@autox.team.net
>>>[mailto:shotimes-admin@autox.team.net]
>>>On Behalf Of Edward Mazurek
>>>Sent: Friday, April 15, 2005 10:46 AM
>>>To: SHOTimes
>>>Subject: [Shotimes] WTB rotors for brake upgrade
>>>
>>>Hi,
>>>
>>>I have a 95 MTX with almost 150K. I want to
>>>      
>>>
>>replace
>>    
>>
>>>the
>>>rotors and do the brake upgrade to the larger
>>>      
>>>
>>rotors
>>    
>>
>>>in
>>>front. What's the best place to get the brackets?
>>>SHONut?
>>>
>>>Also, I'd like to get cross drilled, cadmium
>>>      
>>>
>>plated
>>    
>>
>>>rotors
>>>(all 4). Where's a good place to get them? There's
>>>some on
>>>eBay for $116 + $45 shipping + $30 cadmium plating
>>>      
>>>
>>+
>>    
>>
>>>$2 insurance = $193
>>>
>>>Here's a link:
>>>
>>>
>>>      
>>>
>http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=7967282
>  
>
>>>844&sspagename=STRK%3AMEWA%3AIT
>>>
>>>Anyone have any familiarity with these?
>>>
>>>Thanks,
>>>
>>>Ed Mazurek
>>>_______________________________________________
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>>>      
>>>
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