Forum

[Peter D]

The neoprene seal that fits into the drive end of the primary case.

Does the spring side face the outside of the case or towards the engine??

Should it be flush to the case on the inside or flush on the engine side. ( I would think flush on the inside of the case.

I know these sound pretty basic, but it matches my skill level

[Jools G]

The spring side faces inwards towards the engine (from which side the crankcase pressure will 'jam' the seal against the crankshaft journal).

There are two (probably more like 4!) variants of inner primary chaincase, the earlier type which had a composite form of seal made up of a felt ring sandwiched between 1 dished ring and 1 plain support ring, plus a shim ring, and the later type which used a conventional neoprene oil seal. The oil seal should be fitted flush with the inner 'step' within the chaincase.

The rear seal to the gearbox mainshaft also changed with time, and the MM's fitment with the scissor clutch means that there should be 1 x clutch cable entry + 1 x alternator wiring exit hole in the top of the inner primary, sealed off by a simple rubber gasket and clamping piece.

[Peter D]

Thank you Jools,

The case I have is a later one. Because it will use a neoprene seal, does that mean that the washer and shim are not used?

[Jools G]

If you convert to the neoprene oil seal, the large dished washer plus the felt seal are both dispensed with.

The two other plain (flat) spacers are both retained (they fit inside the oil seal housing recess which faces the engine).

[Peter D]

Once again, thanks Jools.

[Peter D]

The oil seal is fitted flush with inner step in the inner case. The washer and shim are in place facing the engine, and the case is in position with the Allan head screws hand tight and then given a 3/4 extra turn.

The case is straight and there is a 2 mm gap between the case and the crankcase around the crank shaft.
Is that correct? The washer and shim are in the correct position inside the recess on the outside of the case facing the engine.
I would have thought that the two cases should butt up with no gap, but I cannot see how that can happen with the seal set up.

Also, if the case is not in the correct position, it could lead to the primary chain rubbing on the inside of the case and influencing the movement of the crankshaft.

[Jools G]

This has happened to me too - the main bearing 'walked' outwards when the crankcase cracked on my Connie ..... it's unlikely on the lightly-stressed MM though.

1). Check that the main bearing has been pressed right home onto the crankshaft journal and also into the LH crankcase half. The bearing shouldn't protrude very much at all and the inner chaincase should mate flush with the crankcase.

2). Check that the 'spacers' are the correct thickness (.007" and .024" from memory) and that they haven't become displaced from the recess - hold them in place with grease to stop them dropping out during installation.

[Peter D]

The bearing is flush with outside of the crankcase, perhaps a little proud, but virtually nothing.

The washer supplied by Hitchcocks and is on the spare parts page for the 1961 Meteor Minor is .037"
The spacer on the same page is.023"
A combination of .060"

The cavity in the inner primary case measures a depth of .155"

The lip on the crankcase measures .153"

That means with no washers the inner case and the crank case fit together, but since the washer and shim are the width of the cavity, they will always push on the lip preventing a seal.

[Jools G]

P. 14 of my MM parts book for 1961 shows the dimensions just as I recalled them (.007" & .024"); that adds up to a total of .031", and as there are no other washers or shims in this vicinity of the primary case, I've no idea what the .037" item is supposed to be for!

The parts book mentions that there are two types of primary case, those for 'Phase A' engines and those for 'Phase B'. You should be able to tell which 'Phase' engine you have from the engine number - it will either have an 'A 'or a 'B' as the last letter in the sequence for 'Sports' spec machines or a 'C' or a 'D' for the 'De Luxe' version.

The simplest thing to do is to leave them out; as they really have no function in this instance except to fill a gap, there'll be no harm done.

[Peter D]

Thanks Jools G,
The inner primary case is attached, minus the washer and shim.
It all fits correctly and lines up properly. The clutch is fitted, and the engine turns over. So once again thanks for the discussion and the solution.