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Location: The Scottish Border
I’m interested to know what is the “Austin rumble” ?
Is it the flywheel vibrating on the taper when under load?
Bill G
Based near the Scottish Border,
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Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
31-08-2019, 11:01 AM
(This post was last modified: 31-08-2019, 11:04 AM by Tony Griffiths.)
If you replace the rear bearing the rumble will, for a while, disappear - so that's its source. However, goodness knows what sympathetic and interacting vibrations are set up as a consequence of a "loose" main and so amplify the noise/vibration/harshness at various combinations of revs and ignition advance.
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Location: Auckland, NZ
I dunno how other cars with roller bearings (BSA 10) motorbikes etc fare but almost any clearance in Seven rear mains leads to a degree of rumble esp if spark well advanced. A tight fit bearing reduces the tiny initial clearance and so stays quiet longer.
As a matter of interest what are measured journal sizes on Phoenix cranks? If these are all generously over size at the rear bearing clearances would be very small.
Prior to modern oils with their anti rust properties and wwhen cars were subject to a lot of cold running, many Sevens crept about with grossly retarded sparks. I have a stack of 65 and more year old old bearings with tracks all greyish instead of chrome like shine.
Pre WW2 Len Southward of the notable auto museum ran a business specialising in Sevens. He told my father cars came in with the flywheels rubbing on the case!
With the degree and type of use now seems much less of an issue.
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Hi Henry,
Is there any chance I could get a high definition copy of the blue prints.
Email tony.7ca@aol.co.uk
It would help the developement team.
Thanks Tony.