Mailing List flyrotary@lancaironline.net Message #20603
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Apex Groove Specs was Re: Apex Seal Groove Wear
Date: Thu, 21 Apr 2005 20:35:23 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Wendell,
 
According to the Mazda, the spec limits range for clearance between apex seal and slot side  is 0.062 to 0.102mm  as the standard.  They give the limit spec as 0.15mm.  Chapter 2 Part B of the Haynes 1989-1991 Rx-7 (page 73).
 
Ed
----- Original Message -----
Sent: Thursday, April 21, 2005 6:54 PM
Subject: [FlyRotary] Re: Apex Seal Groove Wear

With all the chatter about apex seal slot wear, thought I'd better check my old engine.  Could not get a .1mm gage in the slots beside the apex seal, I think a .08mm would go in.  Assume this is OK.
 
Got my injectors cleared and spraying a good pattern, didn't know that they sprayed with such a force. Rusty, looks like I won't be needing your injectors after all.
 
Wendell
 
 Hi! Kelly
I must of mist Lynn's VST system, I don't understand what those measurements are.  I opened another 91 13b NA today & to my dismay it was toast (supposably a Mazda rebuilt in '99)
I measured at 90deg. to the apex slots with a digital vernier caliper the reading I got on this one were from 2.26 to 2.43 mm the new 2mm seal is 1.91 to 1.94 wide, the max allowable clearance is 0.1mm therefore in this case the widest width should be 1.04mm so this slot has 0.39 mm excess wear at the slot opening. Has anyone actually measured a new rotor? I guess I will buy 2 new rotors now
Georges 
 



 
 Hi! Leon
You have a point regarding air filter use on water, when Mt St Helen (Washington state) erupted the first time I had a shop in Vancouver BC Canada (about 300miles away) even at that distance, one of the fleets of vehicle that we serviced had to have the air filters replaced every second day( even a week the eruption).
 I made the crack about no need for an air filter for a float plane in Canada, but actually much of the time float planes are started on the lake shores with the engine above the ground instead of the water. The other thing about air filters on an airplane, an alternate air source (like a slightly spring loaded flat) should be supplied ( in a float plane case , water could splash onto the element & freeze solid at altitude, blocking air to the intake). On the rotor apex seal subject, I agree with you regarding the amount of wear on the rotor seal slot & seal has to be a lot more than Ed's  to spit out the seals. I drove my used engine supplier nuts yesterday, measured 6 different  rotors  & all were from 2.13 to 2.28 mm, he old me they use these rotors regularly for a long time & never had a problem. Mine are 2.17 to 2.26mm, So I guess I'l have to buy new rotors.
Georges Boucher
 
 
 
 

 
 


 


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