Author Topic: Plunger A10 assembly  (Read 656 times)

Offline DJinCA

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Plunger A10 assembly
« on: 09.06. 2019 16:49 »
Hello, you all were very helpful with my earlier question (was it really 4 months ago?) about the cush drive.  While I have been quiet, I have not been entirely idle.  As I related in my introduction, I received a couple of crates of parts along with my roller '51 A10 Golden Flash.  There was a very dirty and somewhat damaged crankcase assembly along with a much better set of cases, so one of the early tasks was to disassemble and assess what I had.

I think that everyone has had that experience of working to split cases and the don't seem to want to part.  After double, triple and quadruple checking that I had not missed a fastener, I started to apply a little heat in an attempt to soften any sealer that might have been incorporated when they were last assembled.  It was quickly apparent that I needed to clean them up first, and upon cleaning, found this, which may give some impression of "care and maintenance" of at least one previous owner.

Jumping forward, I have the old crankcase torn down and have cleaned up some.  Inside was a large journal crankshaft.  I have removed and cleaned out the sludge trap and had the crank ground.  I have, I believe all of the parts I need to put things back together with one exception.  I don't have 67-0349, listed as "Bearing shim (Drive side)" which would apply for my crankcase set (1952) but perhaps not my crank (large journal)  While this is listed as a shim, it appears to me part of its purpose might be to keep oil from migrating from the crankcase to the primary. 

Can I use this part?  Should I use this part?  I don't see myself getting the case half modified for a conventional lip type oil seal if it is even feasible.  I think my next steps are getting my timing side bush line bored to fit my crank, and working on crankshaft end float. 

More questions to follow.  Thanks in advance.

Dave

Offline Swarfcut

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Re: Plunger A10 assembly
« Reply #1 on: 09.06. 2019 19:15 »
Hi Dave. How you proceed depends on what you have.

 The early case has no oilseal, just that 67-0349 shim which is in fact an oil slinger, just a circular disc with a slightly beveled outer edge. With the outer race removed from the case, you will see the case has an annular groove, where it fits. To assemble, the shim/slinger goes into the case first, followed by the bearing outer race. With the crank and cush assembly in place, the slinger is sandwiched between the inner race and the drive sleeve, so rotates with the crank. The drive side dimensions for big and small journal cranks are the same, so the slinger can be used with a big journal crank.

 The early drive sleeve edge has a spiral groove, and runs  very close in the hole in the crankcase, in an attempt to return any oil back towards the bearing rather than the primary. It appears that on later engines the edge of the drive sleeve is smooth, even though they have the slinger. This was all covered in replies to your earlier posts

 While the unit is apart and being set up for line boring, you may as well have the case opened up to take a seal. It all depends whether the drive sleeve has a scroll or is smooth. An existing smooth sleeve should fit the seal no problem. The seal locates on the bearing outer race, just pushed into the hole from the primary side.

 The slinger is somewhat rare, but you can easily make one from a bit of springy shim stock.

 Early case, slinger type... hole is 46mm. The drive sleeve should be a close fit in the hole.

 Later case, seal type, ... hole is 55.5mm.

 Measurements taken with Vernier Caliper, measured on typical used cases I have to hand. If you decide on a seal, machine the case to match your seal.

 The seal is common on all engines  from its introduction in 1952/53 to the end of S/A production.

 With the big journal crank, ensure the inner sludge tube is removed completely from the crank, sludge accumulates between the tube and the crank bore and is overlooked when folks just remove the end plugs and clean the tube. Remove the tube locating radial bolt and knock the tube out. A new radial bolt is a good idea, well sealed in place with Loctite.

 Swarfy.

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Re: Plunger A10 assembly
« Reply #2 on: 09.06. 2019 20:09 »
G'day Dave.
OMG some people should be kept well away from tools, grinders and welders. The case is still fixable, I doubt the weld has much penetration.
The slinger looks like this https://mikesclassiccyclespares.com/product/67-0349/
If the cases are apart I'd bore to take the seal. I'm kicking myself now I didn't do it 30 years ago!
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline DJinCA

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Re: Plunger A10 assembly
« Reply #3 on: 12.06. 2019 22:37 »
Gentlemen,

Thanks for your information, and I am sorry it has taken me so long to get back to you.    I guess I wasn't really thinking things through, but you both are right that the case will already be set up to bore for a seal when the work is done to bore the bush.  The sleeve in the new duplex engine sprocket has the radial grooving and I found shim/oil slinger available for next to nothing and added it to an order.  I will have one available if I decide not to open the case up for a proper seal, so I should be good to go either way.

I have the sludge trap out and things cleaned up.  I have new bolts, plugs and a tube as well.  I will give it a final clean again before assemble, but will take it to the machine shop when the bush is bored, and wanted to leave them off until that is done.

Thanks again for your help, and I am sure I'll be back with more questions.

Dave

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Re: Plunger A10 assembly
« Reply #4 on: 13.06. 2019 10:40 »
G'day Dave.
The reason I wished I converted to the oil seal is that when she wet sumps (one week and the entire oil tank is in the sump  *eek*) a lot of the engine oil ends up in the primary. I use very slippery engine oil and the clutch doesn't like it. If I don't drain it I can't get up my driveway.
To convert you would need a later cush drive bearing without the spiral groove.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Dave c

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Re: Plunger A10 assembly
« Reply #5 on: 17.11. 2019 19:03 »
hi, putting a 1951 plunger engine together, it has no oil seal but has the oil slinger, the metal shim ,but the cush drive bearing is plain with no spiral groove. the duplex engine sprocket has 3 grooves cut into it, is that the spiral groove to throw the oil back? thanks in advance

Offline Swarfcut

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Re: Plunger A10 assembly
« Reply #6 on: 17.11. 2019 22:12 »
No Dave. The grooves are  to allow oil to lubricate the highly loaded area between the back face of the sprocket and front face of the drive sleeve. Relative movement here only occurs as the cush assembly works its magic, under the considerable spring load.

 Oil slinger and scroll type drive sleeve would be be the way things were done on early engines, oil seal and smooth sleeve on later variants, but as you have found slinger and smooth sleeve are also found. Plenty on this in previous Forum posts. The scroll is in the form of spiral grooves cut in the periphery of the drive sleeve, where the oil seal runs on later engines.

Swarfy.

Offline Dave c

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Re: Plunger A10 assembly
« Reply #7 on: 19.11. 2019 21:05 »
thanks swarfcut, i will try and find a drive sleeve with scroll

Offline trevinoz

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Re: Plunger A10 assembly
« Reply #8 on: 19.11. 2019 21:09 »
You will probably find that your's didn't have a scroll originally. They seem to have been on the long stroke engines.
Much better would be to find one from the later BA series engine and have your case machined to accept a seal.