Allen -
As a general rule the 100 should be much less susceptible to scuttle shake
than the six cylinder cars. I would definitely take a close look at the
outriggers & floorpans and the quality of sheet metal in this area. The
outriggers need to be solid and fresh, if so then that will go a long way to
getting rid of any "shake."
Also, I have always said, I believe the primary cause of harmonic shake on
any Healey is worn front shocks. If you have worn shocks, it will allow the
front wheels to bounce, creating shake at freeway speeds. Replace your
shocks if you haven't!
Cheers,
Alan
'53 BN1 '64 BJ8
On 2/2/06, Allen C Miller, Jr. <acmiller@mhcable.com> wrote:
>
> Has anyone carried out the Bill Bolton scuttle shake mod to a 4-cylinder
> frame? Emily developed a shake 2500 miles after a complete suspension
> rebuild, and various attempts to dynamically balance mitigated but did not
> cure the manifestation -- curiously changing the speed range at which the
> shake was mainfest. Originally I noticed it at 63-69 mph, with sudden
> onset
> and rapid fall-off below and above the range. After balancing, I'm left
> with
> lesser shake in the 54-58 mph range.
>
> I've also noticed fine harmonic vibrations, totally independent of the
> remaining scuttle shake, evident in the mirrors, curiously in the fender
> mounted mirror at some engine speeds, and in the rearview on the cowl at
> others. Would the scuttle mod reduce these as well? (not annoying, and
> rather
> part of the "Flight of the Phoenix" mystique, but I would have to think
> over
> time these would fatigue metal over the time frame I intend to drive the
> car
> (viz, the next three decades, or until my body develops its own scuttle
> shake).
>
> The shop painting the car has also suggested using a number of different
> DuPont seam sealers to pack between the front cowl's undersection and the
> understructure, and to work into the fender-cowl seams. The owner showed
> me a
> number of different kinds on the sample board, some of which are more
> pliant,
> some compatible with different metals and primers, and so on. Any
> experience
> with these products? I have to imagine they would do more good than what I
> discovered had been used at the factory: During an autocross, two
> essentially
> pertrified rubber bulkhead seals dropped onto the carpet, apparently
> having
> been placed as spacers during original assembly (no evidence the front
> cowl
> had been off before). Each was deeply compressed across part of the flat
> surfaces with the markings of frame metal.
>
> All guidance welcome. The panels are off and we'll be doing metal repairs
> in
> the next three weeks.
>
> Allen Miller
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