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Original Message -----
Sent: Saturday, February 04, 2006 6:28 PM
Subject:
[FlyRotary] Re: Atkins errors
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.
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
Thomas;
I understand the niceties of torque
sequence; but it would seem that is all out the window when the engine has been
run about 6 hours, many cycles to full power, and a dozen or more temperature
cycles to 200-210 F; all with the two large bolts loose. As far as I know
nothing untoward has happened, but how can I be sure?
Al