Subject: Time:12:42 PM
OFFICE MEMO Brake Squeal, Moss boxes, and_ Date:6/18/93
On the topic of squeaky TR7 brakes, duct tape, to the back of the pads. Has
anyone tried this? I wonder
what happens to duct tape when you cook it on the back of brake pads.
Answer: the duct tape on my furnace is hard and brittle. The adhesive is baked
onto the ducts. For brake pads I use MossFett (I think its molybdenum
disulphide) a grey gooey stuff I got from the Volvo dealer. That's what they
use and it seems to work. There is also spray-on stuff called Disc Brake Quiet.
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I have a noticeable whine in first and second on my TR6 as well.
Always have. There is a REAL noticeable whine in reverse on every
manual trans I've ever owned, including my '85 honda.
Reverse gears whine because they are straight-cut (ie, not helically-cut).
This is cheaper, compacter and more efficient, but NOISY. Each tooth whacks
in without ceremony as the gear rotates; on a helically-cut gear they slide
in surreptitiously. Ever heard a racing Mini with straight-cut gears?
Early Jaguars (Moss box) had a phenomenal whine in first gear - were these
straight-cut too? Anyone know?
Answer: Yes, the non-syncro first and reverse gears in the Moss box are
straight cut or "spur" gears. The rest are helical gears. In both cases the
involute gear tooth geometry is such that the teeth roll on each other, instead
of sliding. Helical gears have smoother action, less noise and vibration
because the teeth come into contact gradually beginning at one end of the tooth
and progressing across the tooth surface, whereas in spur gears contact takes
place simultaneously over the entire face width.
Ref: "Mechanisms and Dynamics of Machinery" by Mabie and Ocvirk
The Citroen logo originally advertised the fact that they used helical gears.
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Wolseley, on the other hand, goes way back to the start of the century. They
were something of the BMW of their time, providing the police cars seen in
Ealing Comedies, and the Hornet sports model. They were swallowed up
by Lord Nuffield eventually, ending their days as badges on Morris
Minor-based 1500s, Farina 1600s, Minis and possibly 1100s and 1800s too.
Comment: In the early years of Jaguar, when they were known as the Swallow
Sidecar and Coachbuilding Co., they built special custom bodies on Wolesley
Hornet chassis, and called them Hornet Swallows.
Rob
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