yorkshire_spam Posted November 29, 2017 Share Posted November 29, 2017 Hi all,Wimpus' recent gearbox related activities have got me thinking.The RMS8NR/MJ1NR/MS10K - pn 104433 input and output shaft bearings are getting harder and more expensive to source.Current best prices I can manage are around 15 quid per bearing for "European budget quality" or between 30 and 35 quid per bearing for good named brand (SKF/FAG/STEYR etc.)Which got me wondering.... what purpose does the snap-ring serve? Since the corresponding RMS8/MJ1/MS10 bearings are easier and cheaper to source.Is it there for location or retention? Cheers, Sam Quote Link to comment Share on other sites More sharing options...
glang Posted November 29, 2017 Share Posted November 29, 2017 Unfortunately I think the snap rings prevent bearing movement due to the thrust forces developed by the helix type gears used in these boxes. If they were straight cut it would be another matter but then there would be other problems..... Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted November 29, 2017 Author Share Posted November 29, 2017 Quoted from glang Unfortunately I think the snap rings prevent bearing movement due to the thrust forces developed by the helix type gears used in these boxes. If they were straight cut it would be another matter but then there would be other problems..... I thought that too, but I can't see how the bearings could move into the box (due to the internals) and they certainly don't stop the front bearing being pushed out (as I could clearly see on my box when the circlip snapped - the front bearing was pushed about 3mm forwards.I'm wondering if blocking the outer race against the bell housing/tail casing might be possible and serve the same purpose without needing the snap rings.You could quite easily be right though - it could be a VERY stupid idea.I'd also wondered about taper roller bearings.... but that's another story! Quote Link to comment Share on other sites More sharing options...
glang Posted November 29, 2017 Share Posted November 29, 2017 Dont forget that the thrust forces go in both directions depending on whether the car is under power or not. Trouble is we dont know how much force is generated and if some loctite would sufficient to hold the bearings.... Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted November 29, 2017 Author Share Posted November 29, 2017 And looking closely at RKC634 the overdrive adapter casing, there's clearly a recess in the face for the snap ring, so even if the input shaft bearing can move forward the output shaft bearing is going stay where it should.Oh well, probably a non-starter. Quote Link to comment Share on other sites More sharing options...
JumpingFrog Posted November 29, 2017 Share Posted November 29, 2017 I've been trying to source these bearings too, but I'm unable to buy quality ones anywhere. I got sent some NTN ones with a kit, but I'm not entirely convinced these are genuine as NTN's product finder doesn't list RMS8N.One thing I've considered, is buying MJ1 (still quite expensive, all imperial bearings are...), then getting grooves cut in them on a lathe. I've also looked into taper roller bearings too, but couldn't find anything that looked suitable (at least using Timken's bearing finder).There is a similar availability issue for some mini gearboxes, these also use an MJ1 derivative, but these have a step rather than a snap ring... Quote Link to comment Share on other sites More sharing options...
glang Posted November 29, 2017 Share Posted November 29, 2017 Looking at my three rail non OD box the input shaft bearing cant go forwards because its held in place by the oil seal housing and the output shaft bearing cant go backwards cos its restrained by a snap ring on the shaft which itself is fixed by the tail bearing snap ring.Would it be possible to fix a non grooved input bearing by drilling and tapping a hole in the casing adjacent to the bearing so that a bolt could be screwed in to trap the edge of the bearing without interfering with the input gear? Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted November 29, 2017 Share Posted November 29, 2017 There for location and definitely required. You could buy plain bearings and have the slots machined later (should be easy enough with a modern tipped part-off tool) though might not end up much cheaper.The ones we got for the Spit gearbox were very "ordinary" quality - I was almost tempted to re-use the rather weary originals.Nick Quote Link to comment Share on other sites More sharing options...
glang Posted September 28, 2018 Share Posted September 28, 2018 Hi, reviving an old thread as it applies to a three rail box Im rebuilding for my Vit 2L. Ive bought a non OD unit second hand at a bargain 26quid and am pleased to find it in generally good condition. Encountered a few strange things when stripped down like a roller missing from the mainshaft tip bearing (no where to be found) and unfortunately a small pit in the bearing area of the layshaft (otherwise its perfect although there is polishing in the areas where supported in the casing as if its been moving slightly?). Anyway the main bearings are a bit wobbly (don't know if this is normal but will compare it with my 80k box when I take it out) and I wanted to know of anyone's experience with the budget replacements mentioned in the original thread? Thanks Quote Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 3, 2018 Share Posted October 3, 2018 being a single row ball race there will be some waggle/float , but once supported by the flywheel spigot or the tail housing it all holds steady . no float or waggle is possible when all assembled. Quote Link to comment Share on other sites More sharing options...
glang Posted October 4, 2018 Share Posted October 4, 2018 Thanks Pete. I'll probably carefully inspect the four bearings I have available and use the best two. Ive tried contacting a well known gearbox refurbishment company but, as expected, they wont tell me who supplies them with bearings, synchros and layshafts so I'll try to stick with original items...... Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted October 4, 2018 Author Share Posted October 4, 2018 Just to throw my 2p worth in... my suppliers can't get what I'd call branded ones anymore. I can get KSM Japan bearings, but no skf, fag, rhp etc. And the KSM bearings are about 35-40 quid EACH. Quote Link to comment Share on other sites More sharing options...
glang Posted October 4, 2018 Share Posted October 4, 2018 Yes I reckon the rebuild shops must be using the 'chinese' stuff from the usual Triumph suppliers but then their gearbox warranties are probably only a year at best..... Quote Link to comment Share on other sites More sharing options...
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