Author Topic: Quick question timing side bush  (Read 316 times)

Offline Andy75sheffield

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Quick question timing side bush
« on: 21.06. 2020 19:28 »
My first build on a bsa left to me by my dad  sadly past away 4 year ago he restored it in 1980s been stored in attic for 30 years in bits in bubble wrap I’m  just rebuilding the bottom end  the Timing side bush for A7ss the one I took out has a steel outer ring do they have extra meat on the od  aswell as the Id does the -20 +20 and so on indicate to the id brass bush it’s self or the od any help appreciated

Online berger

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Re: Quick question timing side bush
« Reply #1 on: 21.06. 2020 21:55 »
has the crank been re ground. you need to measure the timing side journal where the bearing fits to see what size it is. the steel housed bearings were the original from the factory, some of them might have been re bushed to -10 or 20thou by people over the years. generally a -10 or -20 is a solid lump not a two part set up, have you got the Haynes bodge book all the crank sizes are in there. I would advise reading up on re building the engine from scratch, before you go any further make sure the sludge trap has been cleaned out

beezermacc

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Re: Quick question timing side bush
« Reply #2 on: 21.06. 2020 22:30 »
MCA supply steel cased bushes whereas Wassell supply solid phosphur bronze bushes. There are other suppliers. The outer size of all bushes should be the same. The inner is supplied in 0.010 increments. As Berger says, it is important to check the journal size of your crankshaft before fitting the bush. You need to measure the top v bottom diameter and front to back diameter on the inside and outside of the journal. Also look carefully for a lip at the outside edge of the journal which will indicate wear. I always have the crank ground if I find any ovality or lip. You can get away with up to 0.001" (1 thou) at rebuild stage but most would want to do better than that. If there is any wear in the bush as well the job really needs doing properly. You don't need to take the crank down to the next 010" increment, you can just have it ground round and concentric then ream an undersize bush to suit. I would not recommend doing this yourself unless you have engineering experience as this is one of the most critical parts of your engine rebuild. One course of action, if the journal measures Ok, would be to assemble the bottom end and measure the vertical play in the crank which, ideally, should not exceed 1 thou though maybe 1.5 thou would be the absolute limit; you may be lucky! Remember that the amount of vertical play will have a proportional impact upon oil pressure so this is one area where you shouldn't compromise.

Offline Andy75sheffield

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Re: Quick question timing side bush
« Reply #3 on: 22.06. 2020 06:15 »
thanks guys for the reply

i do have owners workshop manual bsa spares a group catalogue roy bacon twin restoration and  iv printed out all the service sheets out  also iv joined the bsa owners club but waiting for confirmation i have been reading up things but unsure what to do about the crank

 timing side conrod journal out of round by 2 thou and 2mm play side to side no play up or down
the left side no play either way  both shells 1454+ 010

ts journal for bush 1.341.5
journals do have slight signs of ware and friction burn marks
 

beezermacc

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Re: Quick question timing side bush
« Reply #4 on: 22.06. 2020 06:35 »
....sounds like the crank needs grinding. The big end journals will need to go down to the next size but you could consider just having the timing side journal cut round and concentric. All journals should have a radius where they meet the flywheels. An experienced crank grinding firm should have the necessary data. Standard journal size of t/s bush is 1.37 so yours has been reduced considerably already.

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Re: Quick question timing side bush
« Reply #5 on: 22.06. 2020 09:49 »
andy it is a shame beckett & garner shut down they were the ones for putting everything right . there might be a firm called Sheffield motor servicers who could put you right with the crank and bush *dunno*

Offline Andy75sheffield

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Re: Quick question timing side bush
« Reply #6 on: 22.06. 2020 10:00 »
Yes Berger iv heard of Beckett garner
I think iv found a place not to far from me in Sheffield http://www.theenginespecialists.co.uk i

as any 1 else had owt done from here I’m not to keen on posting my stuff to srm any recommendations welcome 👍

Online RichardL

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Re: Quick question timing side bush
« Reply #7 on: 22.06. 2020 15:53 »
Yes Berger iv heard of Beckett garner
I think iv found a place not to far from me in Sheffield http://www.theenginespecialists.co.uk i

as any 1 else had owt done from here I’m not to keen on posting my stuff to srm any recommendations welcome 👍

Based on their website, those Engine Specialists folks seem to have a lot to offer. If it's just the cost of posting to SRM, it's summer, you could take a day at the beach and stop in Aberystwyth on the way. Can't say I could do the same.

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