[T3] Another Strange Noise

["Mark Seaton" <Markse@mo-sys.com>]

<x-charset iso-8859-1>I have noticed over the last couple of weeks a new strange noise coming from
my engine/transmission. It happens as I drive to work along my favourite
rat-run which is full of speed bumps. This necessitates regular acceleration
and deceleration between the bumps and it is on the deceleration at a
particular RPM band and only for a moment, that I get a strange high speed
metal-metal scraping noise sort of like a brake rubbing. It sounds sort of
engine speed but is only momentary. I don't notice it at all when driving
normally at steady speed. It is difficult to investigate as it only seems to
happen when in 2nd gear and travelling at a fair speed. It doesn't happen
when the clutch is disengaged so I can't get close to investigate. My
thoughts are that it must be the flywheel or fan rubbing on something but
only when the gearbox is being back driven and only at a certain RPM. Why
would the gearbox being back driven move the crankshaft? Maybe I have too
much end-float on the crank- I didn't check this when I had the engine out,
but I've only noticed this over the last couple of weeks.
Any ideas would be really appreciated as I can't think of a way of finding
out more at this stage and am just hoping that it will go away the way it
came!

On a more positive note I found an inductive pickup "Peerless Made in the
USA" timing light at my local flea-market last week. It was in a state but
works brilliantly. I had used an in-line type before and was happy that the
timing was right. What a difference- crisp clear view of the marks and I
found I was 2-3 degs over advanced. Adjusted it correctly and she runs much
smoother and would accept a leaner idle mix on the carbs- I'm hoping to get
more than 20 MPG (UK) soon! It really is worth having the right tools!

If I carry on wasting petrol like this it will not be long before I could
have bought myself a pair of those Minnow Fishes! I'm seriously interested
in them and I spoke to the guy who makes them and he reckoned it is very
easy to balance them in pairs- though I didn't understand a word of his
explanation!

Mark Seaton
Orange '73 Fastback, London

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