TABC propshafts

[Clive Sherriff]

Unless it has developed a bend or twist over the last 80 years ! That's quite likely too. >> the TA shaft I am working on has a balance weight fixed so should it be OK [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1546561385&sig=PqAPsCP2uxoo_jhslbqgxA--~D[/img] Virus-free. www.avast.com

On Thu, 3 Jan 2019 at 11:46, jeffrey townsend jeff.townsend@hotmail.co.uk> wrote: Just a further thought on propshafts - the TA shaft I am working on has a balance weight fixed so should it be OK to use as is provided there have been no changes/repairs to it. Regards, Jeff [b]From:[/b] jeffrey townsend jeff.townsend@hotmail.co.uk> [b]Sent:[/b] 03 January 2019 10:17 [b]To:[/b] Roger Furneaux; CLIVE SHERRIFF [b]Cc:[/b] Jan Johnson; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: TABC propshafts Hello Clive, A couple of questions on propshafts that you or others may be able to answer as follows:

[*]Which parts of the shaft should be included in the balancing, e.g. bare shaft only, shaft and front yoke, shaft and yoke and flangesI've always understood that a propshaft should go back in the same orientation to gearbox and axle flanges as it came out to maintain balance. However if the gearbox and backaxle rotational parts are not included in the balancing why is this? In addition with a re-balanced shaft no previous orientation is applicable

I have meticulously aligned my TB propshaft to punch marks rear and front for years. Was I wasting my time? Regards, Jeff Townsend North Cambs UK TA1957 TB0489 Own a TB? Join us at TB80 in May near Oxford to celebrate your cars 80th birthday. Details from Jeff Townsend or Mike Inglehearn [b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] 03 January 2019 09:45 [b]To:[/b] Roger Furneaux [b]Cc:[/b] Jan Johnson; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: TABC propshafts

Whilst an unbalanced prop shaft will produce considerable vibration (indeed, enough to make the car undrivable, and possibly failure) I cannot see how it would affect engine revs. as there is no actual power absorption. Clove m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1546561385&sig=PqAPsCP2uxoo_jhslbqgxA--~D[/img] Virus-free. www.avast.com On Wed, 2 Jan 2019 at 23:14, Roger Furneaux roger.46tc@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

hi Jan - why are you expecting backlash? Although I should point out that whereas a balanced prop-shaft will not magically give you another 500rpm, and unbalanced one will LOSE you that 500rpm... I first heard this many years ago from Henry Stone, author of "The Insomnia Crew" who worked on race and record car preparation at Abingdon. Cheers Roger On Wed, Jan 2, 2019 at 9:22 PM Jan Johnson jgarnaes@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

I ve had two(2) prop shafts rebuilt and balanced at a shop near me in Northern Cincinnati; I read somewhere that

A balanced prop shaft vs. an unbalanced one, can make as much as another 500 R.P.M. increase!? Jan/Fairfield, Ohio

P.S., I m girding my loins for the possible backlash!

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[Clive Sherriff]

Jeff,The recommendation to align the prop shaft to the position of the gearbox and rear axle flanges has never seemed to make any sense to me. The Gearbox and Diff flanges should run concentrically with no axial or radial deflection as long as the bearings are good, so are in effect fixed points with no effect on the prop shaft balance. Whilst the gearbox rear bearing usually remains in good condition, as Roger F will doubtless agree, the bearings at the diff end are another matter, and if the pinion bearings are not on top form, then this will allow the rear flanges some movement which, when it gets bad, could throw the prop shaft off line and that will affect the balance of the prop shaft plus diff pinion shaft assembly. As the axial / radial displacement of the pinion shaft would be quite small anyway, even with a fairly worn Pinion bearing, (unless the cage has actually collapsed) the prop shaft would probably be running fairly true still anyway. I've never seen a problem with a worn bearing, but have had a car in with collapsed pinion bearings and that definitely vibrated to such an extent that it wrecked the rear prop shaft yoke needle bearings. There is of course the other possibility that the collapse of the prop shaft needle bearings caused the pinion bearings to fail ? What's your experience here Roger ? CliveOxford, UK.m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm Clive= =============================================

On Thu, 3 Jan 2019 at 10:17, jeffrey townsend jeff.townsend@hotmail.co.uk> wrote: Hello Clive, A couple of questions on propshafts that you or others may be able to answer as follows:

[*] Which parts of the shaft should be included in the balancing, e.g. bare shaft only, shaft and front yoke, shaft and yoke and flanges I've always understood that a propshaft should go back in the same orientation to gearbox and axle flanges as it came out to maintain balance. However if the gearbox and backaxle rotational parts are not included in the balancing why is this? In addition with a re-balanced shaft no previous orientation is applicable

I have meticulously aligned my TB propshaft to punch marks rear and front for years. Was I wasting my time? Regards, Jeff Townsend North Cambs UK TA1957 TB0489 Own a TB? Join us at TB80 in May near Oxford to celebrate your cars 80th birthday. Details from Jeff Townsend or Mike Inglehearn [b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] 03 January 2019 09:45 [b]To:[/b] Roger Furneaux [b]Cc:[/b] Jan Johnson; mg-tabc@yahoogroups.com [b]Subject:[/b] Re: [mg-tabc] Re: TABC propshafts

Whilst an unbalanced prop shaft will produce considerable vibration (indeed, enough to make the car undrivable, and possibly failure) I cannot see how it would affect engine revs. as there is no actual power absorption. Clove m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm [img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1547341139&sig=6FLyFY_GaNz83fh136ml8g--~D[/img] Virus-free. www.avast.com On Wed, 2 Jan 2019 at 23:14, Roger Furneaux roger.46tc@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

hi Jan - why are you expecting backlash? Although I should point out that whereas a balanced prop-shaft will not magically give you another 500rpm, and unbalanced one will LOSE you that 500rpm... I first heard this many years ago from Henry Stone, author of "The Insomnia Crew" who worked on race and record car preparation at Abingdon. Cheers Roger On Wed, Jan 2, 2019 at 9:22 PM Jan Johnson jgarnaes@yahoo.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

I ve had two(2) prop shafts rebuilt and balanced at a shop near me in Northern Cincinnati; I read somewhere that

A balanced prop shaft vs. an unbalanced one, can make as much as another 500 R.P.M. increase!? Jan/Fairfield, Ohio

P.S., I m girding my loins for the possible backlash!

Sent from Mail for Windows 10