rhouck

EDIT: Answers in Post #5

I have the old Kraftwerks kit. I think it has the V2 tensioner but I'm not entirely sure.

Today it ate the bearing. The tensioner itself seems to be fine, as the pulley, but the bearings in side are dead.

Is there somewhere I can just buy the replacement bearings and/or pulley? I tried Autozone but without knowing an actual car make/model, it was just random guessing.... and issue became that this pulley is REALLY small. I found one that fits the bolt but is too thick of a diameter and I'm worried would hit the supercharger pulley and/or the crank pulley?

Any ideas? All I have gotten so far is call new Skunk 2/Kraftwerks about a new tensioner, but hoping I can find this bearing separately...

rhouck

I am seeing numbers like:

CYS SMR6903 (I guess the one listed here? http://www.cysbearing.com/product_in...products_id/41 )

and

SKF 61903 (guessing this one? http://simplybearings.co.uk/shop/Bea...duct_info.html )


With there being three different tensioner versions I don't know if that's correct for what I need.


And I picked up the Gates tensioner but it requires bracket modifications (which I don't have time for at the moment) and still leaves me needing the pulley/bearing.

Sideways

Bearings are all replaceable. Pop it out and get the numbers off of it. Contact a local bearing supply and get a new one. I got a replacement (not your kit) from a castor builder who had thousands of them in stock. I suggest you upgrade the bearing and avoid this problem in the future. If the numbers are not readable, measure it. SKF is a good brand.

s2kseven

Kindly post the replacement bearing when you find it. I want to buy a spare too.

Thanks

rhouck

Alright, so I believe the 6903 is the bearing for the *old* tensioner. That one had two separate bearings in it. I'm not sure if 6903 is the only one you need or how that works.

My kit has the *new* tensioner from Kraftwerks. This tensioner takes the 6301 bearing. It is a 12mm x 37mm x 12mm bearing.

You can buy this bearing from Kraftwerks/Skunk2 directly for $9.xx. The bearing they sell is a Nachi bearing, P/N # 6301-2NSE9. Nachi (http://www.nachi-fujikoshi.co.jp/eng/web/pdf/B3402E.pdf) states that this bearing is rated at 9,750 N (dynamic load), 4,250 N (static load), and 16,000 rpm.

Because I was not nearby to them and in a time crunch, I sourced another 6301 bearing that was closer to me. This was what was nearby:



FAG 6301-2RSR. This bearing is rated at 9,786 N (dynamic), 4,225 N (static), but only 13,000 rpm. Thus, this bearing may be inferior to the Nachi bearing (or may be more conservatively rated). Time will tell. It was pricier (~$22).

Another bearing I saw (but not locally available) was SKF 6301-2ZJEM. The specs appear to be superior to both, and may be what I try next (if needed -- hopefully not).

It's relatively easy to replace. Remove the snap ring and remove the bearing:



Then replace with your new one:



Make sure to save this inner ring and put in the new bearing! It does not come with your new bearing! The center bore is 12mm on the bearing, but the bolt that holds it into the tensioner is slightly smaller -- this is used to fill that gap.



Bolt it back onto the tensioner and then reinstall on the car.



This got me back on the road and I ran it at the race track all day on Saturday without issue. Time will tell re longevity. I may consider the Gates tensioner upgrade, but seems like somewhat of a pain to machine the bracket (as it will need to be removed from the car).

s2kseven

Thank you for the picture and for the bearing info....

s2k_zunig

Hey guys I lost the center bore to the kraftwerk supercharger does anyone know where i can get a replacement part ?