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chevynut
04-22-2013, 02:34 PM
I have a pair of original 2-piece brake rotors from a late 60's Nova or Camaro. I took them off of a clip myself to use on my Nomad. They have part number 3910881 on them but I can't seem to find much else about them. Seems that most of them were part number 3901098. Anyone know anything about these? Mine look just exactly like these:

http://www.heartbeatcitycamaro.com/store/product/21960/Camaro-Disc-brake-rotor-2-piece-USA-1967-1968-1969-1970-1971-1972/

But they have holes like this one:

http://i35.photobucket.com/albums/d189/jasonchale/001-3.jpg

markm
04-22-2013, 04:22 PM
Those were used on 67-68 F bodies with 4 piston calipers, with OEM 4 piston calipers you must use them. However they also fit 68-72 Chevelle or 69 Camaro with one piston caliper and one piece roter. They used to be worth more than they are now because they were not reproduced, but like most of the crap I hoarded they are now available.

markm
04-22-2013, 04:38 PM
Those roters may have been used on Chevelle or Nova with 4 piston brakes.

Rick_L
04-22-2013, 05:07 PM
Since they are GM they still may be worth at least as much as a repro, possibly more.

Looks like the holes are just for balance.

Any Camaro/Nova/Chevelle with the 4 piston caliper disc brake package would have used this rotor. I was unaware that they were used in 69-72 - I thought the typical one piece rotor and the single piston floating caliper was used on those. But the rotor may be functionally the same.

markm
04-22-2013, 05:16 PM
My 70 SS396 Chevelle had two pirce roters, it had std D52 brakes and was not new when I got it. I scored a pair off a 74 Nova I junked also, actually I have seen quite a few on D52 applications. Always figured they continued to use two piece on some cars after advent of single piston calipers. I actually converted my 67 SS 350 to D52 stuff because 4 piston stuff sucks.

Rick_L
04-22-2013, 06:08 PM
"4 piston stuff sucks"

It did originally, but now there are lots of places that will sleeve those old calipers with stainless sleeves and they are fine that way. Seals are better now too. But that's far more expensive than a single piston D52 caliper that's trouble free for the most part. They only reason you'd want the 4 piston calipers or pay extra for the 2 piece rotors is to restore a car that came with them, or to create a clone of one. For conversions to other cars, just stick with the cheap parts.

chevynut
04-22-2013, 06:11 PM
So do you guys have any idea why the casting number would be different? I can only Google one hit for GM part number 3910881. Part number 3901098 seems pretty commonly used.

markm
04-23-2013, 06:47 AM
"4 piston stuff sucks"

It did originally, but now there are lots of places that will sleeve those old calipers with stainless sleeves and they are fine that way. Seals are better now too. But that's far more expensive than a single piston D52 caliper that's trouble free for the most part. They only reason you'd want the 4 piston calipers or pay extra for the 2 piece rotors is to restore a car that came with them, or to create a clone of one. For conversions to other cars, just stick with the cheap parts.

Rick when I was dirt poor in College I spent what was a fourtune having my 67 Camaro 4 piston calipers sleeved. I was still buying seal kits every two years. About 25 years ago I converted to single piston and have not screwed with it since. Do they make the O ring seals for these like my 78 Vette and my ex girlfriends Vette now have.

markm
04-23-2013, 06:50 AM
So do you guys have any idea why the casting number would be different? I can only Google one hit for GM part number 3910881. Part number 3901098 seems pretty commonly used.

Sorry I never paid any attention to part numbers, just pulled them off and stacked them on shelf.

Rick_L
04-23-2013, 07:30 AM
"Do they make the O ring seals for these like my 78 Vette and my ex girlfriends Vette now have."

I think so. The calipers are the same style, just different dimensions.

You're right, at one time it was very expensive to repair these calipers. Not too bad now, but still quite a bit more expensive than the single piston stuff which by comparison is dirt cheap.

markm
04-23-2013, 08:09 AM
The bores in my Camaro calipers are smaller than Corvette. I still have the stuff in a box.