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BSA A10 to A70 A65 crank conversion #757412
11/28/18 2:05 pm
11/28/18 2:05 pm
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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Servodyne  Offline OP
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Having spent years looking for an A70 crankshaft for my A70 project I decided to bite the bullet and convert an A10 crank when I came across a very good example with large journals. After reading much reference material on the subject I came to the conclusion that there was not much to be gained from using an alternator A10 crank as the drive side shaft is exactly the same length as a dynamo version.
Here is my story;

[Linked Image]

The one thing I wanted to retain about the A70 layout was the 'improved' timing side main bush oil feed and location. My crankcases, although used, still had the original standard bush fitted which was only marginally worn. The needle roller inner sleeve I was thinking of using had a nominal 1.5" OD which was slightly bigger than the std crankshaft size of 1.4985 to 1.499". Therefore the original bush only required the slightest amount to be reamed out to restore the nominal 1.5 thou clearance.
As the thrust face on an A10 crank is of smaller diameter than the A70/A65 the first job I did was weld a annular ring around the existing thrust face so that when it was ground down along with all the journals it would be big enough to cover the entire thrust washer. The photo shows the finished item after grinding and as you can seen the original oil groove is still evident. The journal was ground to 1.250" nominal to give the desired bearing fit to the sleeve.

[Linked Image]

This photo shows the bearing sleeve fitted, after being heated slightly. The annular groove was made using a high speed disc cutter with two discs fitted, guided by two jubilee clamps. I put two holes in the sleeve, one to match the feed hole in the crankshaft and another 180 deg opposite. The theory is in the very unlikely chance it moves some/enough oil will still make it to the big ends through the remaining groove on the crank. This is one of Mr SRM's concerns about sleeving worn shafts. The big difference here is the sleeve will also be firmly clamped by the outboard thrust washer, pinion and worm nut so movement is extremely unlikely.

[Linked Image]
[Linked Image]
[Linked Image]

These photo's show the outboard thrust washer and pinion fitted. The standard A70 pinion which is different to the A65 had to relieved slightly so as not to bottom on the radius on the crank. In difference to the A70 thrust washer, mainly due to wanting it to firmly clamp the sleeve, mine fits over the diameter of the timing side bush journal and not the worm drive shaft. Also, I wasn't keen on the idea of shims under the thrust washer to control end float so I Installed the assembly in the crankcase and found that 8 thou" needed to be removed from the end of the bush to give me the desired 2 thou" of end float.

[Linked Image]
[Linked Image]
[Linked Image]

These photo's show the modifications to the drive side. Strangely the A10 drive side bearing has a 30mm journal which had to be ground down to 1.125" nominal as used on the A65/A70s. Luckily the spines for the A10 crank cush drive are the same as the A70/A65 sprocket and mine where in good condition. the only problem is that they do not extend far enough along the crank so I elected to modify the sprocket rather machine the crank. There should be more than enough engagement on the splines when compared to other makes. Two options that I heard of for accommodating the alternator rotor. Drill and tap for an extension bolt or the more elegant option of a sleeve nut as per Commando. The thread is 5/8" UNF as original. The sleeve nut shown in the photo's was way too long as it turns out so it was cut down virtually in halve whilst maximising thread engagement on the crank. A new keyway was machined at the end of the alternator shaft and fortunately is spot on to the original setting for timing purposes.
I decided to retain the original A10 flywheel as modifying a late A65 one which is slimmed down around the big ends was proving far too difficult. The first thing that had to be done was reduce the outside diameter to that of an A65/A70. Also to remove weight from the big end area I shaved down the sides to 35mm wide compared with 40 mm on the A65. The resulting assembly was parcelled off to SRM for dynamically balancing.

[Linked Image]

This photo shows the engine nearing completion. It's got the later A65/A70 conrods with the steel caps and original pistons, bought at great expense. I did worry that the 1mm shorter stroke would be noticeable, but it looks fine and the slightly lower compression will probably be of benefit.

Please Note; Some of the photo's look horrible and apparently covered in swarf, but it's only particles of dust picked up by the flash.

Thanks for reading, hope it may be of use to someone.


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
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Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757431
11/28/18 5:00 pm
11/28/18 5:00 pm
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DMadigan Offline
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Curious why you decided to grind the drive side to fit the inch size bearing rather than boring the cases for the metric one? Metric bearings are easier and cheaper to come by.
Nice work by the way.

Re: BSA A10 to A70 A65 crank conversion [Re: DMadigan] #757449
11/28/18 7:10 pm
11/28/18 7:10 pm
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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Basically I didn't want to modify the A70 crankcases in any way just in case I got hold of an A70 crank, which I have just recently albeit crazily modified but that's another story. Also I just happened to have a new original Goldie drive side bearing of the same imperial size with wide rollers and a lovely brass cage. The outer ring doesn't have a lip to control end float but then again A70s don't need this as the timing side bush takes control of all that.

[Linked Image]


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757519
11/29/18 3:00 pm
11/29/18 3:00 pm
Joined: Jan 2003
Posts: 36
minnesota
chuckmn Offline
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My old friend George Helm used to convert all his rebuilds on A65 and A10s to the A70 crankshaft. All his flat track bikes were set up this way. After he passed and the shop was closed I ended up with the patterns and directions he had. His one big problem was finding a correct sized thrust washer, he had bought up all the BSA A70 washers he could find and then used a modified tractor washer.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757523
11/29/18 3:36 pm
11/29/18 3:36 pm
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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I'm sure that it's the way to go if you retain the bush. It must help maintain good oil pressure, a bit like putting you finger over the end of a hose pipe. I'll certainly look into it when I strip my A10 down as I'm sure there's just enough room for a thrust washer without having to counter bore the crankcases and reduce bush width as on the A70.


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757612
11/30/18 1:17 pm
11/30/18 1:17 pm
Joined: May 2013
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Rotherham - S. Yorkshire
Allan Gill Offline

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Many thanks for creating this thread, I will print this off as I find it very valuable.

1) Was the sleeve nut something you bought off the shelf (Commando type etc?),

2) How did you lock the rotor in position? is there a key way to stop the inertia of the crank winding off the sleeve nut?

3) on the A70 type bearing plate you have, does this stay fixed to the crank and then spin within the recess in the crank case, or does the crank end spin within the spacer?

4) Theres an irony as your putting an A10 crank into a dove framed OIF, which is what I wanted to do laughing , do you know the paint colour? is it powder or wet paint? and where did you have it done?

5) I have just noticed that the frontal Key hole slot is missing on your A70 cases, Mark Parker welded his up after it cracking I believe, I wonder if the factory found this also... Your cases also look a bit beefier than the A65 ones.

6) Am I right in thinking that the A10 T-S journal is smaller than that of the A65? or have I miss understood that part of the post? I will be having mine end fed, but will have much the same movements otherwise as yourself on this subject

Again thanks for posting and excellent work!!


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Allan Gill] #757658
11/30/18 7:41 pm
11/30/18 7:41 pm
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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1) The sleeve nut was based on the Commando but is slightly longer by about 5mm. A Pity that the A10 crank drive shaft is just too short otherwise a Commando one would do.

2) There's a new keyway a bit further up the shaft that locates the rotor. You can see it on one of the photos. A lock washer fits in the rotor key way in the normal way.

3) The 'bearing plate' or thrust washer is clamped to the crank by the worm nut. It then spins in the recess in the crankcase and controls the 2 thou" end float. see new photos

4) The frame is powder coated RAL7035 dove grey https://paintman.co.uk/shop/bsa-dove-grey/

5) Just checked similar picture of my 71 Firbird cases. They look pretty much to same. There is a key hole slot but it's to the rear of the main bearing. The cases may be beefier, they certainly look rougher and not as well fettled.
6) The standard A10 timing side journal is 1.375" whereas the A65/A70 is 1.5".

[Linked Image]
[Linked Image]
[Linked Image]


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757759
12/01/18 9:16 pm
12/01/18 9:16 pm
Joined: May 2013
Posts: 5,125
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Rotherham - S. Yorkshire
Again brilliant information. The A10 crank should be an almost direct fit with the NKIB5907 combination bearing that has a 35mm ID or 1.377” so depending on the grind on the crank it would only need machining enough to size to be true.

Thank you for the paint tip, did you have yours sprayed?


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757773
12/01/18 11:15 pm
12/01/18 11:15 pm
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NickL Offline
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Looking at those photo's seems like you may have a problem with the fitting of the oil pump,
that thrust seems to be proud of the case.
As for the setup improving oil pressure, it's marginal, the oil losses are still there as they were
with the bush, maybe a little more restricted. The main thing is you can set the endfloat without
splitting the cases and you are running less risk of the sometimes not so captive thrust washer
chewing up the inner case. Also you can run an MRJ1 1/8 drive side main which is cheaper.
Personally, i still think the best way to preserve oil pressure on these old heaps is to fit a full
flow cartridge or canister oil filter. The other thing is to spend time rebuilding the pump properly.


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757774
12/01/18 11:22 pm
12/01/18 11:22 pm
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DMadigan Offline
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I wonder if a better approach to the timing bush would be a two piece flanged bush inserted from each side with a small gap between for the oil passage? That way the thrust can be taken up by a bronze face on both sides rather than the bronze washer on the inside and the aluminum case on the outside.
There would be no problem with the bronze turning in the steel backing since the oil passes between them instead of through a hole. They would have to be align bored after installing but that is necessary with the single bush anyway.
End float can be adjusted with a shim between the outside thrust washer and crank.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757775
12/01/18 11:39 pm
12/01/18 11:39 pm
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NickL Offline
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The snag with that Dave, is the outer one of the pair would be very narrow by the time you've got the recess..
There is no problem running a hard thrust against the softer ally case and remember the natural thrust of the
engine is toward the timing side anyway.


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757808
12/02/18 8:39 am
12/02/18 8:39 am
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Rotherham - S. Yorkshire
Allan Gill Offline

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Nick, what’s your view of fitting a triumph style oil filter in the bottom of the frame so that the oil is filtered before hand instead of after. Easy enough to convert and I should think the head pressure/weight of the oil is enough to stop the pump starving of oil?

LP Williams triumph oil filter

Last edited by Allan Gill; 12/02/18 8:49 am.

beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: NickL] #757814
12/02/18 10:15 am
12/02/18 10:15 am
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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Servodyne  Offline OP
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Originally Posted by NickL
Looking at those photo's seems like you may have a problem with the fitting of the oil pump,
that thrust seems to be proud of the case.
As for the setup improving oil pressure, it's marginal, the oil losses are still there as they were
with the bush, maybe a little more restricted. The main thing is you can set the endfloat without
splitting the cases and you are running less risk of the sometimes not so captive thrust washer
chewing up the inner case. Also you can run an MRJ1 1/8 drive side main which is cheaper.
Personally, i still think the best way to preserve oil pressure on these old heaps is to fit a full
flow cartridge or canister oil filter. The other thing is to spend time rebuilding the pump properly.


The thrust washer does protrude by 3 thou" even though it looks more in the photo. However the thickness of the gasket and the foot of the pump have been suitably cut away' to give 10 thou" running clearance which should be ample barring some sort of catastrophic failure. I would have to disagree with you on the benefits of running this 'closed' system with that of the standard open ended bush. I would consider that the extra back pressure caused by the thrust washer forcing the oil to change directions twice through small running clearances should be well worth the effort. I do take DMadigan's point though about the thrust washer running on the machined face of the aluminium casing. Hopefully clean filtered modern oil should be the answer to that one. I fit paper cartridge filters to all my old British machines.

[Linked Image]


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757873
12/02/18 7:34 pm
12/02/18 7:34 pm
Joined: Aug 2001
Posts: 4,230
argyll. scotland, uk
gavin eisler Offline
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I hope you fitted the DS rear engine plate and puzzle bolt before you installed the motor, its nearly impossible to fit once the motor is in place.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: gavin eisler] #757877
12/02/18 7:59 pm
12/02/18 7:59 pm
Joined: Aug 2013
Posts: 25
England
Servodyne Offline OP
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I know. It's a bitch if you forget it. A mate of mine forgot it on his 72 Lightning and gave the problem to his 12 year old son after he had put the pipes and carbs on. Poor lad tried for hours trying to get it in. lol

You did say it's nearly impossible??


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757879
12/02/18 8:06 pm
12/02/18 8:06 pm
Joined: Aug 2001
Posts: 4,230
argyll. scotland, uk
gavin eisler Offline
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I have made this mistake in the past, I think I was able to finagle the rear plate into place with the puzzle bolt by removing the lower motor mount, leaving in the front mount and lifting the rear a bit, I remember succeeding without having to completely lift out the motor but it wasnt easy , paint got scratched and the air was blue for days,

Last edited by gavin eisler; 12/02/18 8:14 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: Allan Gill] #757898
12/02/18 10:29 pm
12/02/18 10:29 pm
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NickL Offline
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Originally Posted by Allan Gill
Nick, what’s your view of fitting a triumph style oil filter in the bottom of the frame so that the oil is filtered before hand instead of after. Easy enough to convert and I should think the head pressure/weight of the oil is enough to stop the pump starving of oil?

LP Williams triumph oil filter


I don't really like filters in series with the input of a gear pump as they have little suction power. A full flow filter on the return ensures the tank is clean unless
you fill it with iron filings or suchlike.

As for holding more pressure, unless you have the thrusts sealed better or as well as the main bearing, they will pass the oil with little more resistance than
the open bush, but it's better than standard a65. Modern oil makes no difference at all. the thrust face on that side takes next to no load, the trust is toward
the pump side, there is no need for a bronze thrust face, Hardened steel against ally is a good combination.
Shame your leaving it that horrible dove gray colour.


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757904
12/02/18 11:32 pm
12/02/18 11:32 pm
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DMadigan Offline
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Thr thrust washer on the outside does not need to be as large in diameter as what he used since the radial thickness of the bearing is usable thrust surface. That also eliminates the problem of the washer interfering with the pump mounting.
Since, as you say, the thrust is mainly toward the timing side the washer could be thinner also. I would have to look closer at all the parts but it may be possible to not recess the case at all.
The other possibility is to use a roller guide ring on the drive side so the float is controlled there.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757910
12/03/18 12:01 am
12/03/18 12:01 am
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New Jersey USA
Tridentman Offline

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On the equivalent Triumph set up there is no need for the oil pump to suck.
Because the oil flow rate is so small the head of the oil in the "tank" provides positive pressure at the pump inlet.
Not sure of the oil flow rate on an A65---does anyone know?
If it is similar to a Triumph twin then the logic as above would apply.
HTH

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757912
12/03/18 12:03 am
12/03/18 12:03 am
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NickL Offline
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The cases already have that large aperture machined if they are genuine a70 type.
The lined steel housed bush used by the a70 is just a narrower version of the a65 bearing so
using that as a thrust face is not ideal, i don't much like the idea of carving up the oil pump
to allow the washer to clear though, i'd rather recess the washer or as you say, use a thinner one.
The one Steve Wilson did used a one piece bronze bush so it has a suitable face for a thrust
similar to to the one i did, the bronze face is continued out a couple of mill by the ally case,
The washer i used was 2.8mm thick and 50mm diameter sitting about 5 thou below the surface
In all honesty, i think any of these setups will be fine for what they are.
Unless racing or similar the standard setup is good for the expected rebuild life of the engine, probably more.


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Tridentman] #757913
12/03/18 12:07 am
12/03/18 12:07 am
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NickL Offline
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Originally Posted by Tridentman
On the equivalent Triumph set up there is no need for the oil pump to suck.
Because the oil flow rate is so small the head of the oil in the "tank" provides positive pressure at the pump inlet.
Not sure of the oil flow rate on an A65---does anyone know?
If it is similar to a Triumph twin then the logic as above would apply.
HTH


It would mean that the pump would have to be primed each time the filter is changed though.
Any cavitation would be a problem unlike a piston type pump.
Plus if allowed to block, it's doubtful the a65 pump could pull oil past the bypass in the filter if there is one.
I tend to like things a little more idiot proof and it's so easy to fit/change a return line filter plus i can't see
any real advantage.

Last edited by NickL; 12/03/18 12:19 am.

No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757923
12/03/18 3:14 am
12/03/18 3:14 am
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New Jersey USA
Tridentman Offline

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The filter element normally used on Triumphs is the B25 unit---it has no bypass.
Agreed---if it blocks you have a problem---if you don't change the filter element at sensible intervals you shouldn't put a filter on in the first place.
Having said that reasonable filter change frequencies means that blockage should not be a problem.
The advantage in my book is that you are filtering the oil immediately prior to it going into the pump whereas with a return filter you are filtering the oil going onto the tank.
Of course there is no reason why you couldn't filter in both locations---we always say that there are two oil pumps with separate circuits.
BTW on the Triumphs several thousand of the Charlie filters have been sold in UK and more overseas so the basic concept is IMHO well proven.
Installing it is straight forward on 1973 on Triumphs but the 71/72 OIF frames need some piping mods.
I think we all agree that adding oil filtration using a proper filter element is one of the best mods to do on these bikes --I have put several on Triumphs with no problems.
Still looks original and no extra connections to potentially leak.
Just my two cents worth of course.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757948
12/03/18 11:37 am
12/03/18 11:37 am
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argyll. scotland, uk
gavin eisler Offline
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IMO a return line filter is better for two reasons, it provides a useful boost to the oil capacity and it is relatively easy to access and change. I considered fitting a Charlie type filter on my rebuild , but didnt in the end.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757953
12/03/18 1:01 pm
12/03/18 1:01 pm
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Posts: 5,125
Rotherham - S. Yorkshire
Allan Gill Offline

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Rotherham - S. Yorkshire
If im not misteken there is a mod for the B50 where a filter replaces the strainer in the oil feed tube (front down tube) If "a" BSA had a charlie type filter in the feed line i could foresee the cavitation problem, the head pressure pushing the oil will be lessened by the pipe feeding the filter, but as the filter is submerged in the oil, oil can't sit above it and would soak through the filter fast than it will feed oil to the engine.

I do know of one case where it has been sucessfully done. Im not against fitting a filter on the return line, my 68' has this. However it does put a level of back pressure on the system also, but I think this is down to the 68 crank cases dumping oil to the sump, where I beleive post 68 cases dumped into the return feed line.

Anyway I think I've hyjacked this thread enough, appologies Servodyne.

... I still like the frame colour grin


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: NickL] #757991
12/03/18 7:27 pm
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Servodyne Offline OP
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Originally Posted by NickL
i don't much like the idea of carving up the oil pump
to allow the washer to clear though, i'd rather recess the washer or as you say, use a thinner one.


The alteration to the oil pump amounted to a few thou being removed from material at the edge of the hole on it's forward foot. I must admit that it was far from ideal, but a thinner thrust washer wouldn't have given me the protrusion over the edge of the bearing sleeve to ensure sufficient clamping when the crank pinion and worm nut were installed. A recessed washer would have been a more elegant solution but I did think if there was any wear on the thrust washer in the future I could just reverse it.
This problem wouldn't occur with a standard A70 crank as the ID of the washer is the same diameter as the pinon and therefore would be firmly clamp while being slightly thinner.

Last edited by Servodyne; 12/03/18 7:29 pm.

1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757993
12/03/18 7:33 pm
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argyll. scotland, uk
gavin eisler Offline
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I reckon the Charlies filter market is/was mostly as an insurance policy for folk who foolishly got their frames blasted with beads/ shot whatever.

Last edited by gavin eisler; 12/03/18 7:34 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #757999
12/03/18 8:29 pm
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DMadigan Offline
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To help prevent running cavitation you could do what H*rley did and pressurize the oil tank by rerouting the breather back into the tank then adding a residual pressure valve (as sometimes used on brake systems) to the vent line. But, yes, the filter would have to be primed. Just put a syringe on the feed line and suck the oil through.
I made a double filter bottom plate fot the OIF using a Boxster filter inside and spin-on. Generated no interest.
[Linked Image]
I mentioned using two flanged bushes, one from each side. That way the thrust pushes againt the bearing into the case. Pushing against the full width bearing could move it in the case.
Still, if the recess is already there in the A70 case the thrust washer could be smaller in diameter and the thrust washer would clear the pump.
The gap between the bushes can be small, certainly no more than 0.062" and an annular groove can be put into the case so the oil feed is fed through all the way around the gap.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758008
12/03/18 9:23 pm
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Tridentman Offline

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Personally I prefer the return oil filter to be the type that uses the standard Trident filter.
This to me blends in to the bike frame more than the canister type filter as it is more "tubular" in appearance.
I have never come across a problem attributable to the Charlies filter.
I know of a couple of people who feared blockage of the filter unit so much that they used an extended stud through the center of the filter and stacked two B25 filter units one on top of the other.
However this strikes me as not just belt and braces but belt, braces and baling string.
Just my two cents worth of course.

Re: BSA A10 to A70 A65 crank conversion [Re: DMadigan] #758025
12/03/18 10:19 pm
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Servodyne Offline OP
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It's interesting that you mention the Boxster. Being a dry sump engine Porsche elected to place the filter on the return side and not place any restrictions between the oil tank and feed pump. So I guess if that design is good enough for Porsche then it'll do for me. SRM also warn against this in their instructions when you purchase one of their oil pumps.

I like the idea using two flanged bushes with an oil gap in between aligning with the drillings in the crankcase. The outer one would require some form of locking to prevent rotation, but it would allow a plain shaft or sleeve to be used with just an oil hole to feed the big ends.


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758027
12/03/18 10:27 pm
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NickL Offline
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Myself, being a lazy sod, i like to use a return filter that i can change easily, obtain easily, buy cheaply and
not get covered in oil when i change it. It must of course do the job properly.
I use the norton type heads with a small 20/16mm adapter made up so i can use the Z79A filter which is available
for less than $10 at any auto store here, or on eBay, amazon etc etc. Standard on heaps of jap/korean/yank badged cars.
Using a large exhaust type clamp on the oily frame bikes means you can fit the filter in a vertical plane, so easy to change.
On my 69 triumph a smaller exhaust type clamp allows fitting the filter behind the left hand toolbox cover again vertically. Easy.
A simple bent bracket allows vertical fitment to the dry framed a65 off the RHS engine plate. Easy.

Human nature, if a job is easy, you are more inclined to do it. Simples eh?


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758061
12/04/18 2:24 am
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DMadigan Offline
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Servodyne, I am not sure which Porsche your were thinking about but it was not the Boxster. I have a '73 911 and '99 986, both have the filter between the pump and oil system. The 986 does not have an oil tank. The oil sits in a deep sump.
A peg like the Triumph 500 timing bush can be used to keep the bush from turning.
The spin-on filter is what is used on the T595 Daytona and several makes of Japanese manufacturers.

Re: BSA A10 to A70 A65 crank conversion [Re: DMadigan] #758082
12/04/18 8:48 am
12/04/18 8:48 am
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Servodyne Offline OP
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Ok it must be the earlier 911/916 I was thinking about then.

[Linked Image]


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
Re: BSA A10 to A70 A65 crank conversion [Re: DMadigan] #758116
12/04/18 4:16 pm
12/04/18 4:16 pm
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Rotherham - S. Yorkshire
Allan Gill Offline

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Originally Posted by DMadigan
To help prevent running cavitation you could do what H*rley did and pressurize the oil tank by rerouting the breather back into the tank then adding a residual pressure valve (as sometimes used on brake systems) to the vent line. But, yes, the filter would have to be primed. Just put a syringe on the feed line and suck the oil through.



But does harley have they filter in the oil tank or further down the system? I can’t remember how much the oil tank holds but say it’s 3 litres then your looking at around 2kg weight of oil head pressure pushing its way through the filter, as air has a lower density than oil this should be displaced by the oil itself. If that filter is down the pipe by any length then you will need pressure above it to force it down and through the filter (I believe SRM’s refrence to a filter is the canister type)

You could pressurise the tank though, blanking off the cam breather and using a rocker breather linked into the frames top tube. However you will need to know the max pressure you could get away with and have a bleed off valve, as well as a one way valve between the engine and the frame.

If you have a filter of the triumph internal the, you could do a flow rate test by fitting it without the filter, and seeing how much oil flows into a beaker over a set time. Then drain off and refit with the filter and run the test again. You could just use the drain bolt which some have fitted to save messing up any pipe work. Course if there is a difference you need to know what the flow rate is required by the pump. But further restriction by the smaller oil holes through the engine will probably still be the biggest restriction.


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758119
12/04/18 4:37 pm
12/04/18 4:37 pm
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kommando Offline
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The amount of oil in the tank does not create the pressure but its the height above the oil pump, the tank could be a 55 gal drum but if its at the back wheel then there will be no pressure, an egg cup full of oil with a pipe to the pump held at head height will create a lot more pressure. That is how I worked out the minimum strength of the spring needed in a non return valve to stop wet sumping, it was 18" column of oil, volume did not come into it.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758125
12/04/18 5:47 pm
12/04/18 5:47 pm
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Allan Gill Offline

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I was referring to it quenching the filter

Once the filter is quenched your at the same point as if you were running through a strainer. However most of the oil in the rear tunnel is above the height of the pump.

Last edited by Allan Gill; 12/04/18 6:32 pm. Reason: Second paragraph added

beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758131
12/04/18 6:34 pm
12/04/18 6:34 pm
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argyll. scotland, uk
gavin eisler Offline
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How did the filter get on fire?
Maybe I have got the wrong end of the stick, and apologies for swerving off topic, but why does the Charlies type filter need to be primed ?, its sitting at the bottom of a pipe full of oil, its an open cartridge , oil will flow through it as soon as its submerged, there might be some air trapped in the feed pipe between the frame and the pump, that will bleed out through an old pump, a new pump might need the frame pressurised to push through but that would happen whether a filter was fitted or not.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: gavin eisler] #758136
12/04/18 7:03 pm
12/04/18 7:03 pm
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Allan Gill Offline

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Originally Posted by gavin eisler
How did the filter get on fire?
Maybe I have got the wrong end of the stick, and apologies for swerving off topic, but why does the Charlies type filter need to be primed ?, its sitting at the bottom of a pipe full of oil, its an open cartridge , oil will flow through it as soon as its submerged, there might be some air trapped in the feed pipe between the frame and the pump, that will bleed out through an old pump, a new pump might need the frame pressurised to push through but that would happen whether a filter was fitted or not.


Fire? Lol I’m assuming your referring to my saying quenched?

Regarding the Charlie filter, my point exactly. I’ve primed an engine in seconds by starting the bike up
(The journals being coving in assembly line designed for no oil at first start up) it primes a sh*t load faster then 100 kicks on the kicker with the plugs out.


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758167
12/04/18 10:55 pm
12/04/18 10:55 pm
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NickL Offline
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Talk about unnecessary complication and BS.......................

Why not go the whole hog and have a new timing cover die cast with fittings for a filter between the pump and either end feed or
radial feed? (or both as a few of you would probably like!)
Why not just chuck the a65 motor in the bin and fit a honda or kwaka motor?

About 99% of cars have the filter in the return line. Most do 150k+ miles these days with no problem.
How many miles do you blokes expect from one of these old crap motors before rebuild? How many miles do you do in a year?
The sludge trap should be checked at 30k really so the motor's got to be stripped for that.
I ride my bikes quiet hard, frequent use to 7k and expect and get 30k out of them between overhauls.
What advantages/gains are you actually looking for?


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758175
12/04/18 11:43 pm
12/04/18 11:43 pm
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Isle of Wight, UK
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koan58 Offline
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Why that level of hostility NickL?

If the subject is irrelevant to you, why involve yourself in it?

If you are so experienced and beyond these matters, why waste your time junking other folks thoughts?

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758201
12/05/18 4:53 am
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NickL Offline
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Sorry, i take it all back, no offence intended. I wasn't trashing anyone intentionally.
Not being hostile just asking what benefits they are trying to achieve, messing about with stuff that already works.
Any mods to these old crates should be done to improve them in one way or another, for instance Dave came up
with a brilliant design for a good oil pump, yet no-one took that up, a real positive improvement. Modification to the
cylinder head oil feed has been done and proved but no-one took that up either.
If you are racing these things then uprating stuff progressively is sensible as stresses increase, but most blokes
are plodding these around the houses for maybe 1-2000 miles per year. What possible benefit can a dual oil filter
setup be? Many owners are changing the oil before it's done anything anyway. The bottom ends of these bikes
are far more than adequate for general use why piss about modifying and complicating them unless forced into it
due to failures or excessive wear. Build them properly as standard and they last. I sited my own bike as an instance, that's all.
The engineer in me always ask's 'why change this?' what is the benefit? Any development must be an improvement
or it's not worth doing. I could have spent half my working life changing components on working systems to use
more modern technology with absolutely no benefit at all, i f i chose to. I see these in the same way, i cannot help it.

Last edited by NickL; 12/05/18 5:01 am.

No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758203
12/05/18 7:01 am
12/05/18 7:01 am
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Forfar, Scotland
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JER.Hill Offline
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Hi

Well said Nick. Based on realism and common sense as every. I totally agree with you, in that if you can't make an improvement why waste your time.

Look forward to your next posts as always.

John

Re: BSA A10 to A70 A65 crank conversion [Re: NickL] #758357
12/06/18 3:05 pm
12/06/18 3:05 pm
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Rotherham - S. Yorkshire
Allan Gill Offline

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Originally Posted by NickL
Sorry, i take it all back, no offence intended. I wasn't trashing anyone intentionally.
Not being hostile just asking what benefits they are trying to achieve, messing about with stuff that already works.
Any mods to these old crates should be done to improve them in one way or another, for instance Dave came up
with a brilliant design for a good oil pump, yet no-one took that up, a real positive improvement. Modification to the
cylinder head oil feed has been done and proved but no-one took that up either.
If you are racing these things then uprating stuff progressively is sensible as stresses increase, but most blokes
are plodding these around the houses for maybe 1-2000 miles per year. What possible benefit can a dual oil filter
setup be? Many owners are changing the oil before it's done anything anyway. The bottom ends of these bikes
are far more than adequate for general use why piss about modifying and complicating them unless forced into it
due to failures or excessive wear. Build them properly as standard and they last. I sited my own bike as an instance, that's all.
The engineer in me always ask's 'why change this?' what is the benefit? Any development must be an improvement
or it's not worth doing. I could have spent half my working life changing components on working systems to use
more modern technology with absolutely no benefit at all, i f i chose to. I see these in the same way, i cannot help it.



I didn't intend on fitting a filter in the return line, I can't see the point. However a filter in the frame is a much neater solution than having one clamped to the frame, my pre OIF uses the 2CV filter, it generally works fine and there is nothing restricting its removal, also if it does drop oil im not cleaning up crank cases/ frame etc. The pre filter in the OIF does the same job, its clean! I'd also filter my oil before it goes around the engine than aftrwards.


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758363
12/06/18 3:47 pm
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DMadigan Offline
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Putting a filter inside the OI frame is cleaner than a Norton style filter sitting horizontal above the swingarm pivot bolt but the oil picks up dirt from the engine so putting the filter in the feed dumps the dirt in the frame. There are alternatives to the horizontal Norton filter that do not dump oil on the frame. A spin-on filter can be fit behind the frame base plate or even centered on the plate with a little extra work.
I can see your desire to keep it looking stock. I would like to know what you meant by "it generally works fine"?

Re: BSA A10 to A70 A65 crank conversion [Re: DMadigan] #758426
12/07/18 12:51 pm
12/07/18 12:51 pm
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Allan Gill Offline

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Originally Posted by DMadigan
I would like to know what you meant by "it generally works fine"?



The filter in the return line does its job as it should, however I feel it puts more back pressure on the system which dumps more oil to the rockers. Then there is more oil in the crank cases. I know you can T off after the filter in the return line to feed the rockers and whilst I don't doubt that it does work, its more pipe work that I'm trying to keep down. My 68' already has a cooler and a thermostat (however with the thermostat fitted it isn't making the situation any worse than before they were fitted)

If riding the bike at normal casual riding then it doesn't use a drop of oil, If im pushing the bike then it will use oil. It doesn't burn any and has total seal rings, none coming down the guides and it doesn't leak either! however if the bike has been pushed some then you will find that when its cooled down in the garage there will be a small puddle from the timed breather, if I have not been accelerating hard etc etc then there won't be any oil beneath it, but it won't have dropped lower in the tank either. (As i say it was the same before I used the oil cooler).


beerchug
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758498
12/07/18 7:57 pm
12/07/18 7:57 pm
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gavin eisler Offline
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I have an " Anglo bike " IIRC spin on filter mount , cast with an off set so the canister hangs down approx 3" to the TS fro rear wheel centre line to allow rear wheel clearance,these were made specifically for OIF early models and the oil lines marry up very well, it mounts with a typical U clamp and brace, its easy to change 5 minutes tops.. Just googled it , seems they are no longer available or quite probably I have miss remembered the name , I purchased it around 1990 ish. Once my frame sump is boxed up it stays that way till the next major teardown, maybe 10- 15 years, I hate messing with that stuff, changing that internal thing looks like a real chore, personally , i am way too lazy for that.

The required T off for the rocker line after the filter is easily hidden between the carbs, I trimmed the hard tail on the rocker cover union a little to get a neater fit.. With the stock routing you have more pipe on display with the long rocker feed from the manifold.

any additional filter is probably a "good thing" so it boils down to laziness versus aesthetics I suppose.

Last edited by gavin eisler; 12/07/18 8:07 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758543
12/07/18 11:19 pm
12/07/18 11:19 pm
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NickL Offline
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I spy an 'oil filter' thread.............................................................


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758553
12/08/18 12:36 am
12/08/18 12:36 am
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DMadigan Offline
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... and now for something completely different.

Re: BSA A10 to A70 A65 crank conversion [Re: Servodyne] #758624
12/08/18 8:06 pm
12/08/18 8:06 pm
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England
Servodyne Offline OP
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As my closing comment on the subject of OIF oil filters. Due to the woefully marginal capacity of the OIF oil tank, the only thing I would put into the oil tank is oil. An external oil filter on the return obviously helps, not only with capacity but also vital cooling. The feed to the rockers is taken off the return feed banjo so doesn't effect oiling of the rockers. This is my firebird filter which I've adopted onto the A70.

[Linked Image]


1957 BSA A10 Spitfire
1971 BSA A65 Firebird
1971 BSA A70 Lightning
1975 Norton Commando
1961 Norton 99
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