Mailing List flyrotary@lancaironline.net Message #29958
From: rijakits <rijakits@cwpanama.net>
Subject: Re: [FlyRotary] Re: Atkins errors
Date: Sun, 5 Feb 2006 08:53:29 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

 
----- Original Message -----
Sent: Saturday, February 04, 2006 6:28 PM
Subject: [FlyRotary] Re: Atkins errors

In a message dated 2/4/2006 5:56:30 PM Eastern Standard Time, ALVentures@cox.net writes:

A couple of questions: Why are two of the bolts larger?  What is the torque spec on these bolts for the 20B?  I seem to recall 26-28 ft-lbs.  I can’t get a torque wrench on the bolts without removing the re-drive, engine mount and flywheel, but I have a pretty well calibrated arm.

 

Al

When you add torque to those bolts, the bolts closest to them will go under torque.
 
So go through the whole torque sequence several times if at all possible. This has been the case on every engine I have built.
 
Lynn E. Hanover
 
 
 
I don't havea Mazda Manual, but generally in a case like this there are 2 ways to tighten the bolts correctly:
 
a) Tighten 2 opposite bolts until seated - then torque each to spec. All other bolts are tigthtened spreading out from the 2 torqued:
e.g. Torque the 2 big bolts then: 1st bolt to left of one big b. - 1st bolt to the left of the other big b. - 1st bolt to the right of the one big b. - 1st bolt to the right of the other big b. - 2nd bolt to the left...... you get the idea.
 
This way you have the pieces flat together on a "centerline" and "lay" the rest down on each side of this centerline - spreading it out so that no "wrinkles" are created....
 
b) A stepped sequence is shown in a manual: mostly in cross pattern and something like 10 lb/18lb/26lb
 
 
 
FWIW,
 
Thomas J.
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