I have always used "aircraft " grade fasteners for that application and
would never recommend anyone use less than a Grade 8 at the minimum. Also,
fasteners should be replaced each time they're removed. I have seen some
stretch of stock flywheel fasteners when tearing a stock engine down. That
is hardly a location you want imbalance or flexing at speed. Small
additional investment insures you don't lose a foot! (I am one of the anal
ones who does check runout of the flywheel on assembly. When it spins at 8K
I appreciate the balance!)
Russ Moore
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net]On
Behalf Of Mordy Dunst
Sent: Thursday, August 02, 2001 9:12 AM
To: fot@autox.team.net
Subject: flywheel "runout"
I'm of the opinion and subscribe to the concept that AN fasteners are very
good for a host of applications except for flywheels. I beleive sometime in
the remote past Mr. Kastner indicated that flywheels ought to be fitted with
the hardest and non-stretching bolt available. If I recall my #'s AN and
grade 5 SAE are similar in tensile stregnth and can flex a bit before
breaking. This "give" may be ok in certain applications but, flywheel
wobble at high RPM/harmonics is not that place.
I once checked flywheel runout and was surpirsed to see variations in
flywheels that I thought were good. I think that all flywheels ought to be
checked for runout...
Truthfully...who checks flywheel runout when assembling the motor?
I used a Ford off -the- shelf flywheel bolts (They are cheap..) They are
7/16" and just a bit longer but, it has a good shoulder and the excess
threads were cut off with and abraisive wheel. Obviously, the crankshaft
holes were also enlarged to accomodate this bolt.
Mordy
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