(18-03-2018, 10:32 PM)Tony Press Wrote: This is always critical if the front angular contact bearings are the special narrow outer ring pair which must be mounted back to back.
An ordinary pair can be mounted either back to back or face to face.
The housing depth must be always checked in later crankcases to ensure the correct pair of bearings are fitted.
Cheers, Tony.
The "Companion" says they should be mounted so that the thicker outer rings are together - which is, I take it "back to back".
This is irrespective of the housing depth or the width of the outer rings. In regards to those I have the correct width bearings for the housing in the engine I have.
There is no preload on the bearings which is due, I take it, to wear. So I will introduce a 2.5 thou shim to add a bit of preload, which most people seem to think is a good idea.
Other sources say they should be installed with the faces marked "Thrust" together. The set that came out of the engine had "Thrust" on the inner rings, which was on the opposite side to the thicker part of the outer rings.
Which means, I think, that someone has already had these bearings out, and turned the middles round to get some more wear out of them.
So I am using another set that I don't think have been used as much. They are not marked "Thrust", so that confusion doesn't arise. Still need the preload, though, so either they are not a matched pair, or are a bit worn.
I am sure when re-assembled I will still have the "wobble".
Or maybe I will buy a Big Seven, then life will be so much easier!
"But it is a fast, yet often quoted, misconception, that the Austin Eight adopted the Big Seven engine. As has been explained in these columns the latter’s engine is markedly different yet a step forward from the Seven in the modernization process. Without repeating what has been said before, the Austin 8 has a different crankshaft and connecting rods, the entire lubrication system from sump pan to pump is different and the detailing of the valve gear has also been altered as has the manifolding, cooling and even the components for mounting the unit.
That said, the Eight does have a 900 cc (56.77 x 89 mm) side valve engine (the Big Seven’s stroke is 0.1 mm shorter because of a smaller diameter for the big end journals)."
Regarding mounting of Angular Contact bearings on the Austin Seven crankshaft front I add the following- having in mind the flexible Austin Seven two bearing crankshaft-
19-03-2018, 08:11 AM (This post was last modified: 19-03-2018, 08:19 AM by "Slack Alice" Simon.)
(18-03-2018, 11:40 PM)Tony Press Wrote: Talking of the Big Seven - I have again located the website that quotes the differences between the Big Seven and the Eight engines-
"But it is a fast, yet often quoted, misconception, that the Austin Eight adopted the Big Seven engine. As has been explained in these columns the latter’s engine is markedly different yet a step forward from the Seven in the modernization process. Without repeating what has been said before, the Austin 8 has a different crankshaft and connecting rods, the entire lubrication system from sump pan to pump is different and the detailing of the valve gear has also been altered as has the manifolding, cooling and even the components for mounting the unit.
That said, the Eight does have a 900 cc (56.77 x 89 mm) side valve engine (the Big Seven’s stroke is 0.1 mm shorter because of a smaller diameter for the big end journals)."
Regarding mounting of Angular Contact bearings on the Austin Seven crankshaft front I add the following- having in mind the flexible Austin Seven two bearing crankshaft-
Cheers, Tony.
(19-03-2018, 08:11 AM)Slack Alice Wrote:
(18-03-2018, 11:40 PM)Tony Press Wrote: Talking of the Big Seven - I have again located the website that quotes the differences between the Big Seven and the Eight engines-
"But it is a fast, yet often quoted, misconception, that the Austin Eight adopted the Big Seven engine. As has been explained in these columns the latter’s engine is markedly different yet a step forward from the Seven in the modernization process. Without repeating what has been said before, the Austin 8 has a different crankshaft and connecting rods, the entire lubrication system from sump pan to pump is different and the detailing of the valve gear has also been altered as has the manifolding, cooling and even the components for mounting the unit.
That said, the Eight does have a 900 cc (56.77 x 89 mm) side valve engine (the Big Seven’s stroke is 0.1 mm shorter because of a smaller diameter for the big end journals)."
Regarding mounting of Angular Contact bearings on the Austin Seven crankshaft front I add the following- having in mind the flexible Austin Seven two bearing crankshaft-
Cheers, Tony.
Thanks for that, Tony.
That explains the comment in the Companion about the bearings in the "wrong" way round acting like a self aligning bearing.
Given that the crank bends and the housing is a bit worn and the 'case is acknowledged to be not particularly stiff - the "wrong" way round would seem to be better.
Two things: I don't go for speed/revs. I want durability.
If fitted the "wrong" way round, the preload shim goes between the middle rings.
This engine was nice and quiet when starting off, got progessively more rattly when warmed up. Maybe this was because there was no pre-load on the front mains, they got slacker and noisier when warm?
19-03-2018, 09:23 AM (This post was last modified: 19-03-2018, 09:39 AM by "Slack Alice" Simon.)
(19-03-2018, 09:21 AM)Ruairidh Dunford Wrote: Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?
(19-03-2018, 09:23 AM)Slack Alice Wrote:
(19-03-2018, 09:21 AM)Ruairidh Dunford Wrote: Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?
Correction:
on checking the bearings I have, the centre rings project more one side than the other, presumably having been ground to generate the preloading, with the bearings fitted back to back. (Of course, you idiot Harding!)
This projection means there is a space between the outers, if put together the "wrong" way round, of 75 to 100 thou.
Which means they will not fit in the housing properly, they will project too much. To fit them the "wrong" way round, the inners will have to be removed and turned around.....
....which is maybe why they were wrong in my engine in the first place.
19-03-2018, 10:27 AM (This post was last modified: 19-03-2018, 10:38 AM by Tony Press.)
(19-03-2018, 09:21 AM)Ruairidh Dunford Wrote: Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?
What problems can you envisage ?
The bearings are still a pair so radial load is not compromised, the clutch axial thrust is still taken by one bearing - the inner bearing in one case, the outer bearing in the other, both working through the front plate.
Providing the bearings have standard width outer rings the housing depth is the same either way.
The only difference would be the nose of the crankshaft is allowed some slight movement without unduly stressing the bearings under crankshaft whip.
I am not aware of any factory instruction about fitting the angular contact or 'double purpose' bearings other than the August September 1936 Service journal - page 124. Of course the 1936 on reduced width outer ring bearings must always be fitted back to back.
I would think the face to face assembly would cause less problems than the suggestion of fitting a self aligning bearing at the flywheel end, or deep groove ball bearing or bearings at the front.
I cannot quote the result of anyone knowingly using bearings in the face to face configuration.
Simon,
You wrote- "on checking the bearings I have, the centre rings project more one side than the other, presumably having been ground to generate the preloading, with the bearings fitted back to back. (Of course, you idiot Harding!)
This projection means there is a space between the outers, if put together the "wrong" way round, of 75 to 100 thou."
If the outer rings of your AC bearings are 1/32" narrower than the inner they are post 1936 pair and must be installed back to back - check the housing depth is 1 9/16" (vs 1 5/8" for the standard bearings)
(19-03-2018, 09:21 AM)Ruairidh Dunford Wrote: Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?
What problems can you envisage ?
The bearings are still a pair so radial load is not compromised, the clutch axial thrust is still taken by one bearing - the inner bearing in one case, the outer bearing in the other, both working through the front plate.
Providing the bearings have standard width outer rings the housing depth is the same either way.
The only difference would be the nose of the crankshaft is allowed some slight movement without unduly stressing the bearings under crankshaft whip.
I am not aware of any factory instruction about fitting the angular contact or 'double purpose' bearings other than the August September 1936 Service journal - page 124. Of course the 1936 on reduced width outer ring bearings must always be fitted back to back.
I would think the face to face assembly would cause less problems than the suggestion of fitting a self aligning bearing at the flywheel end, or deep groove ball bearing or bearings at the front.
I cannot quote the result of anyone knowingly using bearings in the face to face configuration.
Simon,
You wrote- "on checking the bearings I have, the centre rings project more one side than the other, presumably having been ground to generate the preloading, with the bearings fitted back to back. (Of course, you idiot Harding!)
This projection means there is a space between the outers, if put together the "wrong" way round, of 75 to 100 thou."
If the outer rings of your AC bearings are 1/32" narrower than the inner they are post 1936 pair and must be installed back to back - check the housing depth is 1 9/16" (vs 1 5/8" for the standard bearings)
Tony.
Tony, just rereading this thread as I want to preload my AC bearings, the main downside with face to face is that you are relying on the front lip to preload the bearings, and restrain the outer tracks
In use, whereas back to back the starter dog is providing the preload and holds it all together.
Does anyone do shims to put between the outer tracks.
There seems some misconception about clamping loads. Unless narrow outer bearings are (very wrongly) fitted in an early long tunnel case without packing, the cover plate should never fully contact the case. The clamp tension comes onto the lip. Plus any extra load arising from a bearing attempting to tilt in its housings, as a very rigid preloaded bearing would seem more inclined to do.
Whilst any radial clearance in Seven bearings is audible, I cannot see that end float needs to be absolutely nil. Many other makes with helical gears must operate with several thou.
Cheap remedies are now unfashionable, but for cars not requiring stepped bearings, I suspect a modern deep groove ball race fronted by an old one as spacer would be just fine.
(19-03-2018, 09:21 AM)Ruairidh Dunford Wrote: Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?
What problems can you envisage ?
The bearings are still a pair so radial load is not compromised, the clutch axial thrust is still taken by one bearing - the inner bearing in one case, the outer bearing in the other, both working through the front plate.
Providing the bearings have standard width outer rings the housing depth is the same either way.
The only difference would be the nose of the crankshaft is allowed some slight movement without unduly stressing the bearings under crankshaft whip.
I am not aware of any factory instruction about fitting the angular contact or 'double purpose' bearings other than the August September 1936 Service journal - page 124. Of course the 1936 on reduced width outer ring bearings must always be fitted back to back.
I would think the face to face assembly would cause less problems than the suggestion of fitting a self aligning bearing at the flywheel end, or deep groove ball bearing or bearings at the front.
I cannot quote the result of anyone knowingly using bearings in the face to face configuration.
Simon,
You wrote- "on checking the bearings I have, the centre rings project more one side than the other, presumably having been ground to generate the preloading, with the bearings fitted back to back. (Of course, you idiot Harding!)
This projection means there is a space between the outers, if put together the "wrong" way round, of 75 to 100 thou."
If the outer rings of your AC bearings are 1/32" narrower than the inner they are post 1936 pair and must be installed back to back - check the housing depth is 1 9/16" (vs 1 5/8" for the standard bearings)
Tony.
Tony, just rereading this thread as I want to preload my AC bearings, the main downside with face to face is that you are relying on the front lip to preload the bearings, and restrain the outer tracks
In use, whereas back to back the starter dog is providing the preload and holds it all together.
Does anyone do shims to put between the outer tracks.
Rgds Gene
Gene,
The preload (if thought required) should be two thou. which the front plate will be able to accept if face to face fitting is used.
It is quite difficult to measure the required shim thickness on the bench with an unmatched pair of angular contact bearings and this won't allow for inner ring expansion when mounted.
I was given some excellent advice: " hold the bearings together by the centre rings, clamp one side of the outer rings together, measure the gap diametrically opposite, and halve it to give the amount needed to be added to give the bearings the required pre-load.
Simples.
That is as far as I have got, now. Other things have got in the way and the engine is still in bits all over the garage.
