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input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 3:01 am
by dgym
Hi gents,
in the midst of rebuilding my gearbox and have just removed the input shaft bearing, while parts diagrams show a spacer or washer between the bearing and the gear, I don't seem to have one. .. should I? oddly the washer in the picture doesn't have a number assigned to it.

any help is much appreciated!

-Jim

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 10:59 am
by Craven
Hi,
I think that illustration is of a very early arrangement, the washer you refer to is an oil slinger and I?ve not seen it in later boxes. Over the years Ford have made various modifications in the oil feed too bearings, later gearboxes ( snap ring ) have a fairly major change in the feed/pickup arrangement too the rear bearing.
Ron.

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 11:37 am
by promotor
A number of the 3 rail gearboxes I have stripped come with a bearing with a shield on the inward facing face (ie towards the gear case) but most don't. It would be this bit that I think the manual is trying to represent.
I presume it's function is to stop too much oil getting to the front oil seal and causing a leak (as has been already mentioned by Craven RE oil slinger). Oil can still get to a bearing with a shield by passing inside the first motion shaft and out through the oil drilling. The shield is metal and is part of the bearing and not a part specc'd or supplied separately by Ford or Lotus as far as my experience tells me.
I don't like the shields and the reason being due to seeing a gearbox with the shield completely melted - which I presume would be due to slightly low oil level and the oils inability to get through the first motion shaft to lubricate it, and the bearing subsequently getting ridiculously hot.

When I build a box if I receive new bearings with the shield on I remove it as I prefer more oil and a leaky oil seal than not enough oil and a seized box. My thinking that if for some stupid reason a gearbox has low oil level then the oil might just get into the bearing through splash.

I appreciate that this doesn't over normal running conditions and there's only a few people who would run a gearbox low of oil but it all helps to avoid disaster!

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 5:01 pm
by AHM
It is a shield on the gear side of the bearing.

I suspect that it is to prevent the gear from playing havoc with the oil supply to the bearing. The gear itself would make a very effective oil slinger so I'll guess that is why it is on the gear side.

Bearings with a snap ring and metal shield are expensive, ones without are not. So they are often supplied without. Take your pick!

Of course you can be sure that the guy that designed and tested the box wouldn't have added it if he wasn't sure it was needed and couldn't justify the additional cost.

Read all about input shaft bearing failures and then wonder why!

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 7:17 pm
by Craven
I wonder that this spacer/washer/slinger was ever used, with the bearing pressed against its location shoulder on the gear, the inner raceway snap ring (1) is an exact fit.
Ron.

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 9:10 pm
by AHM
Ron,
Shields fit between the inner and outer race so don't change the width.

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 9:55 pm
by dgym
thanks guys. :D

Re: input shaft bearing, is there a spacer?

PostPosted: Tue Mar 29, 2016 10:58 pm
by Craven
AHM.
Sure, my comments are made with reference to the illustration provided by dgmy in his original post.
I?m aware of front bearings with internal shields, price wise! 6206 NR or 6206 ZNR a ref http://www.wychbearings.co.uk/6206-nr_skf_open.html
Ron.