Hi all, I need some advice please.
I've been stripping down a 602 engine which I had put in my previous 2cv. It turned out to have a loud knocking when accelerating! No wonder, one big end had nearly 2mm play!
I have enough bits to put one together again, not to any great standard. More an exercise to see how they work.
My question is: as per the photo, the oil seal inside the crankshaft for the gearbox spline is not the diameter for either the shouldered part or the shaft itself. I'm assuming that this seal pushes against the chamfered edge.
Is this how it works?
Also, how is the plain bearing in the crank oiled?
Thanks for any advice.

The seal is in the crankshaft just on the needle bearing. The seal is maybe won. Your driveshaft looks rather dirty and not smooth?

Ignore the screws

indian46,
its function in this instance is as a 'dust' seal, not an oil seal, so one of these is a much better bet.
Just park it on the gearbox input shaft, close to its tip and as the gearbox and engine are fitted together, it will find its correct position.
The 'lip' should face towards the oilite bearing in the crankshaft, which should be replaced if a 12mm bar has excessive sideways movement in it.
( If a 1/2" bar fits into the bearing, it's totally jiggered. )
.
https://www.123bearing.co.uk/seal-VA12.php

Thanks for the information. That's helpful.
The shaft in the pix is pretty grotty, I cut it off a knackered box to use as a clutch mandrill.

A comment having seen the insides of this engine. There's not a lot inside is there!