What collet pack for an OS MAX 61 RF engine?

[Bruce H]

Hey guys, I have an OS MAX 61 RF engine I want to install in an x-cell 60 and I am trying to find out what collet pack I will need for this.
Also, does anyone know what the N means in an OS MAX 61 SFN-H or 61 RFN-H engine designation? My engine does not have the N just simply OS MAX 61 RF
Many thanks in advance to any help you all can give me on this.
Bruce :lol:

[DavidH]

The N stands for Normal ( short stroke). If your rear exhaust engine is of the SX series. It would use this collet set.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0546-4

If this is your engine. The above collet pack will work
http://www.osengines.com/history/osm640/osm-1992-max-61rx-h-ring.jpg

If this is your engine.
http://www.osengines.com/history/osm640/osm-1986-max-61rf-h-ring-abc.jpg

I believe this is the collet pack you need for it.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0546-7

I believe the SFN and the SF series had the same crankshaft size.

S is for side exhaust, R is for rear exhaust. N is for normal stroke or short stroke.
No N the engine is a long stroke.

The SFN or RFN had a black anodized square head on it. It was square like the RF head except it was anodized black.

David