Author Topic: A7SS White Metal Timing Bush?  (Read 731 times)

Offline Peter Gee

  • Valued Contributor
  • ****
  • Join Date: Apr 2015
  • Posts: 268
  • Karma: 1
A7SS White Metal Timing Bush?
« on: 18.12. 2016 11:45 »
Pardon more on this endless subject. Is the Haynes manual wrong when it states the A10/A7SS have a "white metal " crankshaft bush? Mine certainly came with the Vandervell composite steel bush with  a bronze-ish sleeve that might once have been flash white metalled?

If this were so and rematalling services are available, would it not be easier to have the engineers re-apply white metal to a good but  just past service limit Vandervell composite bush than have turned a nwe  lead bronze one or say buying a Kibblewhite one? I say this because white metal will be dead easy to line ream?

Thoughts?

Online KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 1462
  • Karma: 12
Re: A7SS White Metal Timing Bush?
« Reply #1 on: 18.12. 2016 18:25 »
Pardon more on this endless subject. Is the Haynes manual wrong when it states the A10/A7SS have a "white metal " crankshaft bush?
Mine certainly came with the Vandervell composite steel bush with  a bronze-ish sleeve that might once have been flash white metalled?

If this were so and rematalling services are available, would it not be easier to have the engineers re-apply white metal to a good but  just past service limit Vandervell composite bush than have turned a nwe  lead bronze one or say buying a Kibblewhite one? I say this because white metal will be dead easy to line ream?

Thoughts?


I think the Haynes manual is right.
The bush you have may or may not be original?
I know at least one person who has had a timing side main bush re-metalled successfully.
The reaming is easy for all metals, once you have the correct reamer set up, not that I've personally done it!
You need to check the existing bush is a good interference fit in the case before deciding to re-use it, many aren't, due to the case going oval or getting worn by a the bush fretting/moving, this means a special bush needs to be made, on mine a special steel bush was made with a pinned bronze insert, so it's easy to refuurbish next time (not that I expect that in my lifetime!).

Hope that helps!
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Offline trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 2903
  • Karma: 67
Re: A7SS White Metal Timing Bush?
« Reply #2 on: 18.12. 2016 20:57 »
White metal was used in the early days but was superseded by the steel backed insert.
You can fit a bronze bush to the housing but be sure to peg it.

Offline beezermacc

  • Resident Legend
  • *****
  • Join Date: Dec 2011
  • Posts: 994
  • Karma: 39
  • Not for the purist!
    • Priory Magnetos Ltd.
Re: A7SS White Metal Timing Bush?
« Reply #3 on: 18.12. 2016 23:01 »
My preference is to have the crankshaft ground down so that it is round, regardless of size, then buy a solid bronze bush and line ream it to fit. I've done this in my own workshop at least five times with good results.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Offline BSA_54A10

  • Wise & Enlightened
  • *
  • Join Date: May 2008
  • Posts: 2018
  • Karma: 32
    • BSA National
Re: A7SS White Metal Timing Bush?
« Reply #4 on: 19.12. 2016 11:02 »
And there was a few mobs who supplied an old steel case with a new gunmetal lining.
I have one down here waiting to go into the long stroke.
Bike Beesa
Trevor

Offline Bsareg

  • Valued Contributor
  • ****
  • Join Date: Mar 2016
  • Posts: 282
  • Karma: 2
Re: A7SS White Metal Timing Bush?
« Reply #5 on: 19.12. 2016 12:09 »
Be careful with the two piece bushes. I've had two where the pegs have broken allowing the insert to turn thus cutting off the oil supply to the big ends. I now turn the bushes from phosphor bronze and hand scrape them into line after blueing. Time consuming admittedly,  but I've never had one fail.
C11,B40,B44 Victor,A10,RGS,M21,Rocket3,REBSA

Offline BSA_54A10

  • Wise & Enlightened
  • *
  • Join Date: May 2008
  • Posts: 2018
  • Karma: 32
    • BSA National
Re: A7SS White Metal Timing Bush?
« Reply #6 on: 20.12. 2016 09:18 »
If you use phos bronze you need to harden the journal or the bush will wear through the crank
Bike Beesa
Trevor

Offline Bsareg

  • Valued Contributor
  • ****
  • Join Date: Mar 2016
  • Posts: 282
  • Karma: 2
Re: A7SS White Metal Timing Bush?
« Reply #7 on: 20.12. 2016 10:20 »
No evidence  of wear or knocking on any of the bikes after many thousands of miles. Maybe  because of regular oil changes, and a few of them are thoroughly  thrashed
C11,B40,B44 Victor,A10,RGS,M21,Rocket3,REBSA

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1430
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: A7SS White Metal Timing Bush?
« Reply #8 on: 20.01. 2017 08:51 »
I ran a white metal bush on my race a10rr for several seasons, its soft so wears rather than the crank. It held up reasonably well spinning up to around 7500 on the track, but on a routine check found it had started to break up so converted two engines combined bearing and end feed and that has taken another 4 years abuse, but is now due for a check over.
Finding someone experienced in white metal is critical if you go that way.
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand