rogerguzzi Posted January 18, 2019 Report Share Posted January 18, 2019 Hello All I have my single rail gearbox and overdrive in pieces to cure some oil leaks after 30,000 miles I am replacing all bearings and seals and o/rings in overdrive The 1st motion shaft needle bearing cage had broken so I thought I would get one from my usual bearing supplier so I measured the hole and shaft 25mm and 18mm and I think the old one was about 13 mm long The bearing spigot is 20mm long? And there is a 0.105” spacer in the hole and 0.210” at the other end. So I ordered a 19mm long one of Good quality! (INA I think So with the bearing in the hole and a 0.080” spacer at the other end it all fits! The rollers in the new one are 15mm long and 10mm in the old one! So why will this not work better? 5mm more bearing area so more support So what do we all think What have I missed? The hole is under cut at the bottom so it could be ground to the bottom the cage may not be so well supported here but then it is only there to keep the rollers apart Roger Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 18, 2019 Report Share Posted January 18, 2019 The spacers are probably just to protect and position the cage ends , bear in mind they can be in contact with shafts at different rotational speeds but reckon you plan will work ok. I tried to reclaim a bore with a full sleeved needle cage but unable to clear the lube holes in the base of the teeth and oil starvation caused a short life. Pete Link to comment Share on other sites More sharing options...
johny Posted January 18, 2019 Report Share Posted January 18, 2019 Hi Roger, you show the dimensions in mm but isnt it an imperial size bearing? Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 18, 2019 Author Report Share Posted January 18, 2019 1 hour ago, johny said: Hi Roger, you show the dimensions in mm but isnt it an imperial size bearing? Hello Johny No they are metric it was a right old mixture by then but in saying that you will find way before that there was a lot of metric used in car and motorcycle industry ! Roger Link to comment Share on other sites More sharing options...
johny Posted January 19, 2019 Report Share Posted January 19, 2019 Thanks. Ive attached a page from the TR7 manual that shows the single rail internals (presumibly the same design as those used in other models) and as you say it looks like there is room for a longer bearing. Maybe the original idea was to ensure there was sufficient space for slight variations in the two shafts positions due to case casting differences, thermal expansion, bearing wear etc. Triumph TR7 gearbox.pdf Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 19, 2019 Author Report Share Posted January 19, 2019 Hello Johny It is the same drawing in the Spitfire manual even same plate number A37-017A I will take photos today and a lot more measuring but it has got to be better? As this I a told is a weak point! Roger Link to comment Share on other sites More sharing options...
johny Posted January 19, 2019 Report Share Posted January 19, 2019 Its not so much of a weak point in your gearbox as its a vast improvement on the much smaller bearing used in my 3 rail unit. I think with yours the layshaft bearings are probably the weakest area as they are the same in both types of gearbox and certainly undersized for the 2L six..... Link to comment Share on other sites More sharing options...
68vitesse Posted January 19, 2019 Report Share Posted January 19, 2019 Triumph used some standard metric bearings i.e. the half shaft bearings in the differential. My Vitesse three rail gearbox was converted to the larger main shaft tip bearing. Regards Paul Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 19, 2019 Report Share Posted January 19, 2019 i did the same fed up with the 1\2" failures got a stem gear modified by m papworth to take the 18mm spigot and keep the orig clutch disc with the 18mm spigot mainshaft . some use a dolly set up with a rolled spline and change the disc to suit . Pete Link to comment Share on other sites More sharing options...
68vitesse Posted January 19, 2019 Report Share Posted January 19, 2019 My car uses a single rail Dolomite 1850 clutch, only difference is the friction plate as the input shaft is fine spline one. Regards Paul Link to comment Share on other sites More sharing options...
johny Posted January 19, 2019 Report Share Posted January 19, 2019 Roger, what are you going to do with the layshaft? If its in pretty good shape maybe best to reuse it as the pattern replacements dont always appear to be very good in that their surface hardening is poor so the rollers wear through it quite quickly..... Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 19, 2019 Author Report Share Posted January 19, 2019 Hello All I have had a good look and measure and to me it all looks if it will fit and give a bigger bearing area. The measurements are Spacer 0.210” Spacer 0.105” New bearing 0.735” (19mm = 0.745”) Old bearing 0.525” (13.5mm = 0.531”) So leave out thick spacer and fit thin spacer were the thick one would be (next to hub) Here are the photo’s to show how it will fit You can see from the blue how it sits in the middle The bearing cage is slightly deeper at the ends so will be supported in the bore although there is an under cut! The old one tends to cover the oil hole slightly So to my eye it looks like an upgrade? Roger Ps I will reuse the layshaft gear as it looks ok with new needle rolllers Link to comment Share on other sites More sharing options...
68vitesse Posted January 19, 2019 Report Share Posted January 19, 2019 Looking at your pictures have you used grease to hold things in place on assembly?. I have always used petroleum jelly as l understand it melts into the oil. Regards Paul Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 19, 2019 Report Share Posted January 19, 2019 thats micrometer blue used to show up contact facings what are the center pop marks in the end of the cone about ??? Pete Link to comment Share on other sites More sharing options...
68vitesse Posted January 19, 2019 Report Share Posted January 19, 2019 57 minutes ago, Pete Lewis said: thats micrometer blue used to show up contact facings what are the center pop marks in the end of the cone about ??? Pete In the fith and sixth pictures down, definitely not blue. Regards Paul Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 19, 2019 Report Share Posted January 19, 2019 Aha youre on about keeping the chip,shield central etc. ok If the chip shields had the right diameter they wouldnt need goo to hold them , only needed on the layshaft thrusts If you try dissolving grease or PJ in EP90 both are about as bad as each other pete Link to comment Share on other sites More sharing options...
johny Posted January 19, 2019 Report Share Posted January 19, 2019 Roger is the original inner spacer (0.210") standard? It doesnt look like the item shown in the manuals.... Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 19, 2019 Author Report Share Posted January 19, 2019 36 minutes ago, johny said: Roger is the original inner spacer (0.210") standard? It doesnt look like the item shown in the manuals.... Hello Johny That's what has been in there for 30,000 miles but it was me that built the gearbox out of at least 2! So its any ones guess I will have look through my other bits to see if I can find another unless some one has one they can measure? And yes the grease was to hold shim in place while pressing bearing on(I will wash it off before assembly) Roger Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 19, 2019 Author Report Share Posted January 19, 2019 4 hours ago, Pete Lewis said: thats micrometer blue used to show up contact facings what are the center pop marks in the end of the cone about ??? Pete Hello Pete I have no idea not done by me but gearbox built from 2+ Roger Link to comment Share on other sites More sharing options...
johny Posted January 19, 2019 Report Share Posted January 19, 2019 Theres some experts on here who Im sure will be able to tell us for sure.... Link to comment Share on other sites More sharing options...
JumpingFrog Posted January 19, 2019 Report Share Posted January 19, 2019 I think the pot marks might be from hardness testing at the factory. Ive seen it on my gearboxes too... Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 19, 2019 Report Share Posted January 19, 2019 Well they have no significance in gearbox design , assembly or strange they are positioned equi spaced about the rock over lugs on the baulkring , which can be anywhere ...very odd. From my production experience Its unlikely hardness testing would be done at 6 locations, but someone knows ?? Pete Link to comment Share on other sites More sharing options...
rogerguzzi Posted January 20, 2019 Author Report Share Posted January 20, 2019 On 19/01/2019 at 21:31, Pete Lewis said: Well they have no significance in gearbox design , assembly or strange they are positioned equi spaced about the rock over lugs on the baulkring , which can be anywhere ...very odd. From my production experience Its unlikely hardness testing would be done at 6 locations, but someone knows ?? Pete Hello All I have a second 1st motion shaft with exactly the same punch marks? (they are in line with baulk rings tags?) but they could be anywhere? I wonder if it was some way of helping production assembly? (I can not see how but then I have never worked on an assembly line!) Roger ps the plot thickens? Link to comment Share on other sites More sharing options...
Pete Lewis Posted January 21, 2019 Report Share Posted January 21, 2019 It could be the grip/drive on the copy lathe , the end faces would be faced and there has to be a initial centre before boring to cut the outline there wont be a chuck so thats the best i can suggest as part of the machining processing. Pete Link to comment Share on other sites More sharing options...
JumpingFrog Posted January 21, 2019 Report Share Posted January 21, 2019 3 hours ago, Pete Lewis said: It could be the grip/drive on the copy lathe , the end faces would be faced and there has to be a initial centre before boring to cut the outline there wont be a chuck so thats the best i can suggest as part of the machining processing. Pete This seems more likely than hardness testing, I've dug out a picture (very out of focus) of mine. Certainly has way too many marks to suggest hardness testing... Anyway, not something worth worrying about, as they all have them. Back on topic, this is an interesting modification, I'm aware that the cyclic load from an OD's pump does seem to put more pressure on these. Have you considered if the new spacer needs to be hardened? - I've never checked if the original ones are or not... Link to comment Share on other sites More sharing options...
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