Oil seal behind roller bearing on '47

[Brandis]

For sure, you guys are weary of my entry level questions.   I'm used to fitting oil seals on bigger engines where they sit behind the flywheel and are, in no way involved with setting the crankshaft drift.  But, looking at the drawings, the seal is a press fit into the inner diameter of the cylindrical space machined into the case, followed by the roller bearing.  I have just discovered that the oil seal I bought is loose on the shaft and loose inside the case.  But. assume that I get the right one.  My experience is that they are a fairly hard polymer. 
So when you press the bearing in and do the assembly to determine the # of drift shims, am I to believe that the seal will never flatten a bit after use and create a greater drift?
If I had the real seal, It might answer that question for me. 
If only my f@#king parts book would arrive, I wouldn't be flailing about.

[Brandis]

Or, unlike larger engines, does the seal somehow press into the bearing and do seal between the outer, stationary bearing race and the inner, spinning bearing race.  That would seem weird to me but that might mean that seal I have is correct.  If this info is in the Hayne's manual, I've missed it.

[Brandis]

Unlikely though it might seem, the seal I was sold can be pressed into the bearing up against the roller cage. The inner diameter works. But the outer diameter doesn't match the outer race and I can't imagine the roller cage rubbing against the seal is a good idea. I've read my manuals again and they assume that the oil seal install is obvious.  Surely someone in the Forum has run into this.  I realize the being #280 puts it right in the dread first 500 which had a raft of problems. They stopped the assembly line at #600 and re-thought some design decisions, so life for me is interesting.
So, I'm flailing here.

[muskrat]

G'day Brandis.
I don't know that much about Long Strokes. I didn't think they had a crank seal. The 53 and later had seals. I just converted my 51 to use a seal which meant boring the case and a different 67-2053 https://draganfly.co.uk/shop/74735/cush-drive-sleeve-some-rust/#67-2053 to a 67-2071 https://draganfly.co.uk/shop/74747/cush-drive-sleeve-1596704990/#67-2071
The main bearing is fitted into the case from the inside up against a shoulder, the seal is fitted into the case from the outside. A few center pops hold it in.
Cheers

[trevinoz]

The long stroke engine doesn't have a roller bearing but has a ball bearing. there is no oil seal, just a slinger between the bearing and the case.

[Swarfcut]

 Trev's on the money here. The early engine does not have a seal. Instead there is an oil slinger, simply a pressed steel circular shim (67 1239) which goes into the bare crankcase first, followed by the bearing, BSA Part No. 67 1240
 With the crank fitted and the drive sleeve and cush all tightened down, the slinger is clamped between the bearing inner race and the drive sleeve and rotates with the crank. Drive sleeve is a close fit to the crankcase hole, some sleeves have a scroll in the periphery, others have a plain edge.

 Later design BA Series crankcases have a seal, and a smaller diameter to the drive sleeve periphery. Later type drive sleeve fitted to an early case results in a gap between crankcase and sleeve, and engine oil transferred to the primary case.

 All this well documented in previous posts, extensively covered in Cush Drive and Primary Problems.

 The Longstroke  engine uses an imperial deep groove ball race, not a roller race as on the later shortstroke design. This latter race is metric, so the crank and crankcase locations differ and they do not interchange. The ball race means that on final assembly there is no crank end float.

 The ball race has a bore of 1 1/8", OD is 2 13/16"  Width 13/16".  This bearing is also used on the early A50 and A65 Unit Motors. Draganfly's online Parts Catalogue tells all. Drags list its real world identity as MS 11, so a fair choice of international source, quality and price. The shim you can cut from a bean can......

 Muskys Mod adds a seal to the early shortstroke motor. Don't know if this is possible on the Longstroke cases because of the different size of bearing housing. Best left as original.

 Swarfy.

[Brandis]

As always, I'm in awe of you guys.

[olev]

or buy a sealed ball bearing and dig the inner seal out.
cheers

[Swarfcut]

 Time moves on and MS11 has morphed into MJ1.1/8. available as open, steel shield or rubber sealed.

 Metric dimensions for easy comparison are Bore 28.58mm, OD. 71.44mm, Width 20.64mm, so compare the new bearing with the crank shaft diameter and crankcase location. If a later type roller bearing has been sent, it's the wrong one.

 Olev's suggestion will work, but the slinger shim will still be required to keep the drive sleeve in the correct alignment with the crankcase face.

 Replacement crankshaft should have steel conrods, not the later Alloy type. Forging number is 67 220. In an example to hand, this forging number faces the timing side on both rods.

   Look out for worn splines and damaged threads. Timing side has a left hand thread, which carries the oil pump drive worm. Essential that this runs true, they can be found a little bowed from abuse. Fairly soft, so treat with care. If the basics are fine, you can move onto the world of crank renovation. Plenty on YouTube for the later crank, but the basic procedures for cleaning and grinding are the same. Finding the correct timing gears is a different ballgame when the time comes, but there is an easy fix.

 Swarfy.