Centre main

[Tom and Maria]

How do I tell if the centre main is on the right way round? I have the crank in place and all the pistons fitted but have just read on another thread about the centre main being on a right and wrong way round. I guess this is to do with the tab on the bearing?

Can I tell whether I have put it on right or wrong without removing it again? I do hate fiddling about with those tab washers...

Thanks, more questions to come as the rebuild progresses...

Tom

[bmcecosse]

Shell location tabs together...... Why bother with tab washers? Later A series didn't......

[Tom and Maria]

So can I tell without undoing it? Is there a mark or something I can see?

Tom

[bmcecosse]

No - fraid not. It's only two bolts!! Usually if wrong way round....the crank won't turn.

[Tom and Maria]

The crank turns beautifully, so hopefully it is okay. Still worth removing to check?

Incidentally, the pistons are quite tight in the bores. As I was adding them the crank got progressively harder to turn. Everything is very well oiled and the big ends are beautiful, just the rings quite tight in the bores.

I can still turn it all by hand. sound normal? I've only ever rebuilt moped engines in the past, so not really a comparison.

Tom

[MarkyB]

Sounds fine.

[IslipMinor]

Tom,

If the sump is still off, I would remove the centre main bearing just to check. The bearing shell tabs must face each other. If the cap has been fitted the wrong way round, the crank is usually very hard, if not impossible, to turn, even without rods/pistons fitted.

[bmcecosse]

With pistons fitted it should still turn very easily by hand. 'I can still turn it' sounds far too tight to me.......

[philthehill]

An easy way to check if the centre main is the right way round without stripping more than removing the sump is to check the orientation of the mounting bolts for the oil pick up filter gauze bracket. If the cap is the wrong way round the bolt on the centre main cap will not align.

[bmcecosse]

Good point Phil - I've been messing about with Minis far too long!!!!111

[Tom and Maria]

Great advice, I knew there had to be a quick way to tell, hadn't thought about the oil pick up.

Pistons move steadily, I can turn the engine over by the flywheel bolts (which gives almost no leverage) so I'm hoping they are just a good solid fit rather than too tight a fit.

Many thanks,

Tom

[bmcecosse]

That doesn't sound so bad now... 'by the flywheel bolts'

[MarkyB]

With a spanner I should think!

[Tom and Maria]

The flywheel isn't on yet, but the bolts are in for safe keeping so are easily gripped. I'll admit it isn't easy, but it can be done.

The proof of the pudding will be in the first run...

Tom

[bmcecosse]

Be sure to run up the oil pressure (you have primed the new pump...?) before attempting to start it.....