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Posts: 25
Join Date: Jun 2009
06.20.2011, 09:42 AM

very interesting thread, and yes i know its old old is still great

i hope anyone can answer some of these questions and/or provide pics of the parts.

Originally Posted by Finnster View Post
The diff mod has several advantages, the biggest of all being a huge and rugged diff. Not only are the teeth really, really meaty in the Cen pinion and ring gears, but the spider gears are also larger and a stronger steel than the Savage diffs. Also, the diff uses 8x16mm bearings throughout, so more reliable bearings as well.

>> do anyone know the mod size of the teeth on the CEN diff, being 26t it must be another pitch than stock savage (43t or 29t). theres a load of teeth info, ust wondering if anyone knew.

Cen Diff parts, and comparison to Savage Pinion, Ring Gear, and Diff Output Cups of a Sav XL:

>> can anyone provide comparison pics/weights of the CEN vs spider diff:
- 10t vs 8t spider gears
- 20t vs 14t spider gears

>>what screw (8) sizes are needed to clamp together the CEN diff parts, do CEN have a kit for this? and does this work with a stock savage flux diff, meaning only the clamping/center part (diff case/cup?) of the CEN diff used with stock savage diff parts ?

>>does the savage diff output drive shaft cup need shimming when used with CEN spider gears, and CEN 3mm shaft pins etc.?

The Mod is fairly straight forward. The Cen diff is a std 1/8th size. The Savage output cups do need to replace the Cen output cups.

>>why is that ? dogbone ball sizes ? what are the size of the CEn diff output shaft-drive cup ?

The holes are centered properly, so the only real work need is to increase the thru hole for the drive pins from 2.5mm to 3.0mm.

Note: Not pictured but later installed are Cen Cross Pins. These are optional and not required, but are one more bit for strength, as well as less oil needed to fill.)

>>will these work with stock savage spider gears ?

One Diff to Rule Them All:

Remember that the Cen ring gear is smaller than the Savage's. Therefore the drive pinion will have to reach further in the diff case to mesh with the diff. You will need several 8mm shims to do this. I used a total of 2.3mm worth of shims to get the proper mesh. YMMV.

>> whats ymmv ?
>>whats the reason to clamp up the pinion in a vice for shimming ? did you drill it or sand it ? How many flats do the CEN input pinion have ? it doesnt use a step screw like m5x3mm, but a m5 grub/set screw ?
[*]I used hot glue to plug the hole in the Cen pinion. Not sure this is necessary. as the drive cup is closed.

>>so you filled the hole in the pinion with hot glue, what does this exactly do ?

  • One diff I had came with hex screws and grease, another with oil and phillips head screws (these were loose.) Otherwise they were the same. WTH?

    >>what diff ? the CEN or the savage diff ?
  • The Cen Drive Pinion is held by a 5mm setscrew, rather than a 5mm drivepin like stock. Easiest way to get the pinion back in is to just pull the stocker straight out the diff case, leaving the drive cup on the center dogbone. Then just push the new pinion straight thru onto the drive cup, making sure to align the flat spot on the pinion for the set screw. Discard drive pin.

    >>what does above mean, unless using some cvd condom or cvd cover ? easiest way to get pinion back in thru the bearings ?
  • The Cen gears are very, very hard. I easily drilled thru the 4 Savage output cups with the same bit w/ little wear. I needed to enlarge a hole on the spider gear brace for the cross pin to align properly, and it was a major PITA. It took forever and it dulled the bit. The cen gears are really really hard.

>>that sounds great! i like how the cen diffs use back plates for the small spider gears, rounded and decreasing te diff volume, making the grease not accumulate in the corners. Though a wrecked diff might act suicidal when little space it to throw away the 'baby teeth'. So I would like to know how to replace a savage diff cup with a CEN diff cup/center clamp piece.

If you manage to destroy these diffs.... Jesus I don't know what you are doing. At least the parts are cheap!

>>a little royalty is not too much to ask for anyone. Holy diffs, they rise again after 3 days no ? (lol)
can anyone show a pic of comparison of the savage cup (any kind) and the CEn diff cup/clamp piece?
sorry for quoting the wrong way, dunno how to quote right, a tip would be nice if applicable. Please post links to other threads of CEN difs /savage converted diffs if you know some good ones :)

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