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Hi,

Can someone please explain to me how is the Rotax Piston Ring Spanner (ring compressor 876967) supposed to be used? The pistons are already installed on their connecting rods.

I thought I new from watching a video of an individual rebuilding a Rotax engine (not a 912) using this tool and the tool is removed once the rings are in the cylinders by sliding it out at the bottom of the piston, fitting the tool between the piston and crankcase and the slot on the tool slides out of the connecting rod and studs (with some gyrations). However, the tool seems to be too wide (25mm) to fit between the piston and crankcase (20mm). What gives?

Can someone help me solve this Rotax puzzle.

Regards,

Chris  

  • Re: Rotax Piston Ring Spanner (compressor)

    by » one month ago


    The way you described is correct. Sounds like that psiton is not pulled all the way out to give you the space to slide it off.


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Rotax Piston Ring Spanner (compressor)

    by » one month ago


    Thanks for confirming I had the procedure right Roger,

     

    Could it be it was not in TDC?? Maybe, but I could swear I checked. I would be surprised if it wasn't but given that you confirm the tool will work as I expected I can't see any other reason. To be honest I was so concerned about pushing the tool in and then not been able to remove it that I gave up on it.

    Ended up modifying my old Lycosaurus ring compressor (which turned a one hour job into a whole day affair) but it worked like a charm (but now I'll have to get one if I need to work on the other engine 😀 ). Now my cylinders are in but .... I wonder about the tool. I kind of liked how it works.

    Regards,

    Chris

     

     

       


  • Re: Rotax Piston Ring Spanner (compressor)

    by » 6 weeks ago


    We have seen this problem. The simple answer is that Rotax are manufacturing the tool too large, and as standard it does not allow removal from the piston once the cylinder is fitted. We have had to remove around 5mm from the narrow end of the tool. Just wish that Rotax would make the tool right in the first instance !


  • Re: Rotax Piston Ring Spanner (compressor)

    by » 6 weeks ago


    Did you guys get the right one?

     

    876967 Piston ring spanner 84 mm for piston diameter 84 mm/3.13 in.

     876978 Piston ring spanner 79.5 mm for piston diameter 79.5 mm/3.1 in.

     


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Rotax Piston Ring Spanner (compressor)

    by » 5 weeks ago


    Hi guys

    The Rotax tool works just fine.  To use it simply be sure that you are at TDC first.  The cylinder studs must be out if the pistons are on the rods.  Align the rings as per the manual and then lube the inside of the ring tool with some oil.  Place the ring tool on the piston and be sure to have the gap facing directly up to the top.   Now the trick here is to simply hold the piston in the palm of your hand and pivot the piston till it touches the rod.  you can now slide on the cylinder and when you have all the rings captured, keeping the piston at the extreme angle as stated, drop the ring tool down and slip past the rod and out.  You must do this with the piston and cylinder at the extreme angle to clear the crankcase opening. 

    Cheers 


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