Author Topic: Crank end float  (Read 4855 times)

Offline Slide

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Re: Crank end float
« Reply #15 on: 06.01. 2013 17:32 »
Hi Muskrat, thanks for the comment. Good to hear I have come up with something similar to someone as experienced as yourself. I have used the Forum quite a lot to help with my rebuilding of an A7SS - my first experience wth BSAs *smile*. Having just finished the project I thought it was about time I actually joined the Forum - looking forward to giving back some of my lessons learned and picking up a few more tips too..
If you'd like a quick story (a bit off topic) - I have a family history dating right back to the mid 1800s in BSA. My surname is Aston, a well known name in Birmingham where BSA were based. My uncle tells me my great grandfather was one of the original founders of BSA (a gunsmith). So I thought I should get hold of a BSA machine to tinker with (about time as I'm in my 50s now)! All the best for now..

Lambretta LD150 1956 ~6 hp
A7 SS 1958 ~30 hp
Ducati 996 2001 ~ 128 hp

Offline olev

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Re: Crank end float
« Reply #16 on: 07.01. 2013 12:01 »
Brian,
This thread rings a bell.
Didn't you build a motor using a ball bearing main with no float?
I was interested in this as it always seemed to me to be the proper way to design an engine.
How did it behave?
hope the new year is treating you well.

Online Brian

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Re: Crank end float
« Reply #17 on: 07.01. 2013 12:16 »
Yes, the plunger A10 bitsa I built I used a ball bearing. I've only done about 2,000 miles on that particular bike so far, when it gets to about 40,000 I'll know for sure !

I did it as a "see what happens" experiment. The ball doesnt have the radial load ability of a roller but I believe in a low stressed motor it will be adequate. That motor is running 7.25-1 with a 356 cam.

When BSA introduced the A65 for the first few years they went back to a ball bearing. Late BSA Bill (RIP) used ball bearings in his motors and swore by them.

The big advantage of course is you dont have any end float to worry about, when the cush drive is done up the crank is held in place by the bearing.

Offline huddie

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Re: Crank end float
« Reply #18 on: 21.01. 2013 15:09 »
Hi to you all, Here's the latest on my endfloat prob. Thought I'd got it right but when I did what I thought was the final assembly not only have I got no end float but as I tighten the cases the crank tightens up to the point where it is difficult to turn.
I haven't repaced the timing side bush or the drive side bearing, both being in good nick as the bike had only done about 200 miles since a rebuild before the thin endfloat shim broke up.
Am I correct that if the shimming is wrong ie to many then it could cause the symptoms of the crank going tight?The crank spins fine with the cases together, tapped with a mallet and the nuts done up finger tight. but as soon as I apply any tension to the nuts (done a little at a time and in sequence) the crank needs effort to turn and then a little more tension and it tightens up. The tension applied is only a little past finger tight nowhere near what I had it done up to when checking the float.
Now also as I am about to take it apart again and go back to square one I want to get the bearing inner off the crank without damaging it. It has been built with a bit of bearing tight on the inner so it might not come off to easily. I have access to a puller like the one in "Slides" reply but my worry is getting the jaws far enough under the bearing so that it pulls against the inner not the roller cage. How does one do that?.
Regards Huddie

Offline Goldy

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Re: Crank end float
« Reply #19 on: 21.01. 2013 16:01 »
Hi huddie. If the crankcase bolts where tight when you did the end float, and you obtained the three thou float then simply assembling would not change anything, so I would look for something else. You ask about removing the bearing, I use a small chisel which I ground down to a very shallow angle. Tap the chisel in behind the bearing a little bit at a time each side until the bearing moves enough to be able to get a small puller behind it.
All the best Goldy
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Online bsa-bill

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Re: Crank end float
« Reply #20 on: 21.01. 2013 18:37 »
Quote
not only have I got no end float but as I tighten the cases the crank tightens up to the point where it is difficult to turn.

this is exactly the same problem I encountered, unfortunately I can't give an explanation as the shop I took it to (with another new timing side bush) said they had done exactly the same as they did the first time but this time it was perfect (well they would say that wouldn't they).
My suspicion based on little experience or skill is that the first line bore they did was off line or off centre and the final tighten just nipped the crank up, not very scientific I know but the best I can guess, someone here with more know how re line boring might like to comment, but I think it might be a plan to take it back to whoever did it for there opinion
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline huddie

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Re: Crank end float
« Reply #21 on: 21.01. 2013 20:59 »
Hi Bill, Mine hasn't had the bush or the bearing changed. It was stripped because of the broken shim. It was all running fine before so it should be alright now! but it isnt. Back to the question in my last post, will it tighten up if there are two many shims??
Regards Huddie

Online chaterlea25

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Re: Crank end float
« Reply #22 on: 21.01. 2013 21:19 »
Hi Huddie,
"Back to the question in my last post, will it tighten up if there are two many shims??"

Yes it will  *sad2*
To shim it correctly all the crankcase bolts need to be fully tightened, before measuring end float
Check the both case halves are level at the crankcase mouth
sometimes the cases need a little tap to align properly

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline Goldy

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Re: Crank end float
« Reply #23 on: 21.01. 2013 22:23 »
Huddie. just a thought but whilst its been dismantled have the crankcase alignment dowels got damaged or missing.
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Offline huddie

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Re: Crank end float
« Reply #24 on: 22.01. 2013 08:38 »
Thanks Chaterlea and Goldy, its got to come apart so I will check the dowels and go through the shimming exercise again. Anyone any idea what the torque should be on the crankcase bolts?.
Regards Huddie

Online Billybream

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Re: Crank end float
« Reply #25 on: 22.01. 2013 10:12 »
Hi Huddie.
Been following your thread with interest, you will struggle to find any official torque settings for the crankcase half bolts/nuts, I have used typical settings off A65 as a guide for same thread size (already suggested on another thread) , secret is to keep them the same value. The other really useful tip is to use a dummy bearing to set end float.

Torque wrench settings (Dry)
BSA A50 & A65 Unit Twins                1962-65    1966-68    1969-70
Flywheel bolts                                 30lb/ft    30lb/ft    45lb/ft
Connecting rod nuts                         22lb/ft    22lb/ft    22lb/ft
Cylinder head bolts 3/8"                    25lb/ft    25lb/ft    28-30lb/ft
Cylinder head bolts 5/16"                   25lb/ft    25lb/ft     
Cylinder head nuts 3/8"                     26lb/ft    26lb/ft    31-33lb/ft
Cylinder barrel nuts 5/16"                  18lb/ft    18lb/ft    18-20lb/ft
Oil pump stud nuts                            7lb/ft    7lb/ft    8-10lb/ft
Clutch centre nut                       70-75lb/ft    70-75lb/ft    65-70lb/ft
Kickstarter ratchet nut                      60lb/ft    60lb/ft    55-60lb/ft
Rotor fixing nut                                60lb/ft    60lb/ft    60lb/ft
Stator fixing nuts                          10-15lb/ft    10-15lb/ft    5-7lb/ft
Crankshaft pinion nut                       60lb/ft    16-18lb/ft
Carburettor flange nuts                    10lb/ft   10lb/ft    10lb/ft
Manifold stud nut 5/16"                    12,5lb/ft    12,5lb/ft     
Manifold stud nuts 1/4"                    6lb/ft    6lb/ft    6lb/ft
Zener diod fixing nut                        17lb/ft     
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline Slide

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Re: Crank end float
« Reply #26 on: 23.01. 2013 20:20 »
Hi
when I used the bearing puller (see picture above) I very gradually squeezed the jaws closed and re-positioned the puller as necessary as the bearing started to pull away. I found pullers to be so much more effective than for example using a fine chisel to start it off. A puller keeps the force really square which is essential. I was probably pulling on the outer shell to start with to get it moving, can't quite remember..
good luck with it
Lambretta LD150 1956 ~6 hp
A7 SS 1958 ~30 hp
Ducati 996 2001 ~ 128 hp

Offline huddie

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Re: Crank end float
« Reply #27 on: 24.01. 2013 15:14 »
Hi All, Thanks for the info Slide, Softly softly seems to be the way with the puller, it was definitely pulling on the roller cage to start but it came of eventually, not so sure using bearing tight is such a good idea. Thanks for the torque info Billybream, the case nuts were not on there but the rest will come in handy. So I got it all apart and started from scratch again, guess what it all went back together again and this time its fine. Finished up with 1.67 thou endfloat wich looks fine. I did use a new bearing and as for what was wrong before, I can only guess, but I think it may have been that the bearing outer did not go into the crankcase square. I didn't have an appropriate size sleeve for the press and had used three sockets one on top of the other to get a deep enough sleeve to clear the crankcase studs which were still in the l/h side.
So today before fitting the new bearing outer I bought a suitable sleeve, 39mm deep socket did the trick, very cheap compared to a bearing sleeve kit.
I have done the case nuts up to 20 ft/lbs, any comments any one?
Just the remainder of the rebuild to do now, roll on Spring.
Regards Huddie

Online trevinoz

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Re: Crank end float
« Reply #28 on: 24.01. 2013 20:13 »
Huddie,
                   If you heat the crankcase, as you should, the bearing outer will drop in.

Trev.

Offline a10gf

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Re: Crank end float
« Reply #29 on: 26.01. 2013 23:00 »
Slide, am appreciating the endfloat measurement process and picture.

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