After splitting the crankcases to get to the crankshaft, I didn't notice there wasn't an oil seal on the sprocket side. But now I'm about to put the engine together, it dawned on me I was missing something: said oil seal...
However, I fail see where the oil seal should be. There just doesn't seem space for it.
It's a late alternator engine and -seen from the inside- there's a bearing, another bearing, an empty space (maybe the second bearing has shifted during splitting?) that seems too big for an oil seal and then the hole through which the crankshaft end goes. That's a close fit around the shaft.
In that hole, there's a slot in the bottom, going straight through. I first thought this might drain the oil, but it's going to the outside of the crankcase.
What am I missing?
Thanks in advance for thinking with me.
Tim
This sounds like you have a…
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OIL SEAL
Hello,
i stripped my 1960 model 50 engine down a while ago i did not see an oil seal. but i think someone mentioned there was one listed .so mine must have gone missing.there isnt one fitted now anyway. almost sure it looks similar setup to my 19s engine casing in photo
barry
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Crankshaft seal position
Yes there is a crankshaft oil seal but it's fitted from inside the driveside crankcase.
See the responses to Richard Salt's similar question here on April 5th 2022.
In Barry's photo, it is fitted between the timed crankcase breather and bearing 1 (the outer bearing).
From my memory (not as good as it was) when I built my 1960 ES2 the seal was hard to obtain as the width was thinner than usual
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Oil Seal
On my 62 ES2 there was no seal nor a place to fit one as far as I could determine. I believe that the function of the timed breather is to draw outside air in through the down facing port in the outside spigot for just a short intervale at 30 degrees each side of BDC. A passage in the crank that goes from the big end drive side bearing to the timed port when functioning properly will create a slight negative pressure in the crankcase preventing leakage. My crankcase had a hole from a too long tap for said spigot resulting in insufficient negative pressure and leakage. Once sealed with a bit of JB Weld and installing the missing ball stop breather I have no leak and no seal.
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You might be onto something…
Thanks all!
You might be onto something there, Paul G. I'm embarrassed to say that I forgot about the spacer.
Is the part on the photo what you mean? There isn't a anti-clockwise groove on it, but it was situated between the bearings.
And the illustrated picture was very clear and helpful Barry! Together with Paul H.'s explanation, and Ian's input I think I get the picture now. I had a look at the RGM website and there's an oil seal there, stating it for use on alternator engines from '59. That's perhaps why not everybody has one.
Looking at my crankcase, adding up the thickness of the two bearings and the spacer, there's no room left for the oil seal, unless it's wafer thin. Maybe my engine is a bit earlier. Or the cases are older than the crank. Who knows...
It's reassuring to know, though, that not everybody has an oil seal and I don't hear stories of oil loss.
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I have a very early 1959…
I have a very early 1959 alternator engine (C30), as a spare, and it does not have the recess in the drive side case for the oil seal that every other one I have seen had, I assumed that this was an early production mod. but perhaps it was actually an error, and there are others without it?
The seals can be obtained from any decent bearing factor, but will probably need to be ordered in, because it is a bit of an oddball.
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Mine's an early '59 engine…
Mine's an early '59 engine too, which makes yours less likely to be an error. I'm going to run it as it is and see what happens. Fairly confident it'll be fine.
A spare engine is a very good idea. Especially now I'm riding a road going Model 50 and am going to race one. I'll keep on the look-out...
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This sounds like you have a missing thrower ring/spacer thrust washer! It will have an anticlockwise rotation groove around the periphery to channel the oil back into the crankcases.