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Re: Flywheel retainers?

To: richard.r.olson@faa.gov
Subject: Re: Flywheel retainers?
From: "Robert M. Lang" <lang@isis.mit.edu>
Date: Wed, 3 Mar 2004 08:59:06 -0500 (EST)
On Tue, 2 Mar 2004 richard.r.olson@faa.gov wrote:

> While prepping my '72 for the 5-speed installation, I ran into some 'extra'
> fun; as in, the flywheel needed resurfacing and the rear main seal needed
> replacing.

Well, might as well do it while you're in there. :-)
 
> My question relates to the two rectangular 'straps' that are sometimes
> found under the 4 flywheel to crank bolts.  My '72 doesn't have them, my
> '73 did, Bently's doesn't mention them (at least in the Flywheel R&R
> section), Haynes has a picture of them, but nothing like a "If you don't
> use these, your flywheel will fall off." warning.
> 
> So, what's the general consensus of the list?  Don't bother (I'll have to
> order them, and lose another week waiting for them to arrive), or 'Better
> safe than sorry'?

TR6's _never_ had these. I'll bet the Haynes book has a picture of a
TR3/TR4 flywheel install.

These locking straps are a bad idea in most circumstances. Not only can
they wiggle around and score the bolts (causing a potential stress riser),
some of the less reputable sources sell straps that "crush" under load
leaving the torque settings non-existant.

Leave the straps out, they don't belong there.

Note: if you bought new bolts, thoroughly check them for rough spots. I've
bought a couple of different batches of them in the last few years, and on
some of them the heads had "burrs" where they contact the flywheel. This
isn't that big of a deal if you are using a stock flywheel, but it's a
guarantee crack on an aluminium unit.

I chucked all the stock bolts and went with 12-point NAS fasteners from
ARP. The bolts and washers (special washers are needed) cost under $20 and
will not fail. Period.

The stock flywheel bolts are a notorious failure point on any motor that
spins more than 5k RPMs (ever). I and I mean _ever_. I've seen a few cases
where one engine "buzz" to 6K resulted in sheared bolts.

Put in the best bolts that you can find for this application.

> Thanks,
> Rick Olson, digesting

regards,
rml
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