A65 timing side bush

[ferretjuggler]

I need to find somewhere that is competent to fit and line ream a timing side bush to my '72 A65 crankcases
I've got a nice standard crank to go in with very little wear, it doesn't need a regrind.
Can't get the sludge trap plug out, so I might get in machined out like the last triumph one I had done.
PLEASE ! I really don't need to be told about SRM and their roller bearing conversion.
I know all about those and I won't be fitting one, no matter how unwise some people may deem this to be.

What I need is to find somewhere with the machining skills that were around fifty years ago.
Probably not too easy these days.

[EDDIE SIMPSON]

there is an engineering shop in northants who do this work on bsa s all the time. TL engineering ? someone correct me if i have their name wrong.

[ferretjuggler]

Thanks for that.
I'll look them up.
Maybe a bit far from me but I suppose I could always send the crank and cases to them.
20 years ago I would have gone to Autocycle Engineering in Dudley, but I'm not sure who is running it now.
They did the head on my TR6C about 30 years ago, everything was spot on.

[cdsdorset]

Yep T&L
They grind the crank round, make their own Bush and then ream to match the crank.

[ferretjuggler]

I'm not finding any ovality on my crank TS journal or the big ends.
Measuring about 0.001" undersize according to my micrometer, dunno how accurate it is.
Must have come from an engine that has done very low miles indeed.
I've just been reading up about A65 cranks, and apparently they messed with the crank dimensions when they went from a ball race DS bearing to a roller.
So fingers crossed that I've got a late type crank to match my late cases.
I've got some careful measuring up to do.

[EDDIE SIMPSON]

if there is no wear on the timing side journal  you could find a ready sized bush [ metal outer type ] and then as long as your careful  inserting the new bush avoid any machining. if you do have a tight spot - engineers blue and round needle file. that was the way in the post bsa days with rubbish wages.

[bikerbob]

Also it is worth remembering that thre are 2 different bushes for the early models and the later models the flanges that locate them in position are of different thicknesses.

[ferretjuggler]

Also it is worth remembering that thre are 2 different bushes for the early models and the later models the flanges that locate them in position are of different thicknesses.

As usaual, I find that I've opened up a whole can of worms, because I want to do something unconventional.
I want to go back to the original BSA bearing configuration from 1962.
A deep groove ball bearing on the drive side which will control axial float, and a timing side bush that doesn't have a thrust function.
I've discovered that not only did BSA alter the crankcase machining, but they also altered the dimensions of the crankshaft too.
Plenty of scope for mismatching of parts!
I could always get hold of an early  set of pre 66 cases and crank, but then my late '70 onwards type barrels won't
fit the crankcases.
I could fork out on a roller bearing conversion, but I really don't like them.
Or I could just go with the standard '66 to '72 BSA set up, but to my mind shimming between a lipped roller bearing and a oil fed bush is a terrible idea.

[chaz]

worth having a word with a decent engineer with years of practice on engines.
may be able to come up with a bushing solution. its the sort of thing we used to do on our crankcases but they did run at lower revs.
thats when we had a machine shop with skilled men not 6 machines and a dozen loaders.

[EDDIE SIMPSON]

if you decide to buy a pre 66 set of crankcases with 5/16" barrel studs then srm sell a drill and tap set specifically for modifying studs to 3/8" for later barrels.
i ve always thought that pre 66 crankshafts were more plentiful  than later ones and possibly less abused. the very early a65 cranks had 2 sludge trap plugs like the a10 or a7. later ones only one plug. the later engine timing side bushes have always been in better supply than early bushes.
totally agree regards shimming roller bearings. time consuming .

[ferretjuggler]

if you decide to buy a pre 66 set of crankcases with 5/16" barrel studs then srm sell a drill and tap set specifically for modifying studs to 3/8" for later barrels.
i ve always thought that pre 66 crankshafts were more plentiful  than later ones and possibly less abused. the very early a65 cranks had 2 sludge trap plugs like the a10 or a7. later ones only one plug. the later engine timing side bushes have always been in better supply than early bushes.
totally agree regards shimming roller bearings. time consuming .

Thanks for that.
I was aware of the two sludge traps on the early cranks, but I only recently became aware of the '66 dimension changes
It's not the time consuming aspect that I onject to, it's just bad engineering IMHO.
Any plain bush with thrust washers is going to exert an axial thrust away from the bearing due to the oil pressure.
On an automotive crankshaft there are thrust plates on both sides so that it cancels out.
I believe that BSA finally found a solution to this with the A70 TS bush - it locates the crank on both sides - but too little too late to save the unit twins.

[EDDIE SIMPSON]

or bsa could have designed an outrigger plate and bearing with the stator plate to shim endfloat there rather than having to split the crankcases.