Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 https://www.canleyclassics.com/triumph-spitfire-mkiv/1500-mainshaft-and-gears from most listings its unfortunate but you have a 1500 single rail sleeve at 29t in a 3 rail box from my experience the single rail hub is a loose fit on the 3 rail mainshaft i have not found enough to say if a single rail sleeve will fit a 3 rail hub but think your box is a hotch pot of mixed up evolution the hub part numbers are different 1 rail vs 3 rail best maybe to pick up a slave 3 rail 4 sycn box Pete Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 yes I can see a Dolomite 1500 3 rail box has 33 on hub and 15 on layshaft but the reverse ratio is different to the Spitfire VI/1500 (all other ratios the same) so you should have a different number of teeth.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 dont forget this box of darrens is a spitty Mk IV 4 sync there are small variations but layshafts for mkIV 3 rail and 1500 single use the same lasyshaft cluster https://www.canleyclassics.com/triumph-spitfire-mkiv/1500-constant-pinion-countershaft-and-reverse-shaft-gears pete Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 well thats interesting so if Darrens layshaft has 15 teeth and it needs a 21 tooth idler plus 33 tooth hub (seems the Mk1 Vitesse had a 34 tooth hub which strangely is shown as being interchangeable)... Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 however if he has 13 teeth on the layshaft the 17 tooth idler and 29 hub are indeed correctly matched.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 the problem is the 34 t in the WSM is i believe a good old triumph typo its always been 33 on 3 rail 4 sync boxes the fit and interference with first must be down to the wrong hub unit 3 rail and single are very different part numbers for a reason you only get 29 t on a single rail sorry i dont have a pair to compare , but as said I have had the wrong ones in a spoof box i acquired and they dont work unless you want a rattling good fit Pete Link to comment Share on other sites More sharing options...
Peter Truman Posted November 19, 2019 Report Share Posted November 19, 2019 Somewhere in the previous posts on this thread there was comment re selecting 1st & reverse together, I put the single rail internals into a Vit/GT6 3 rail gearbox case, a couple of issues I had were The reverse selector lever (106254) wouldn't engage the reverse actuator (147394), serious realignment of the reverse operating lever (106254) was necessary as recommended by I think Marcus, after some serious bashing (2.7lb small sledge ex TVCWB Water Board in the NE of England 50yrs ago!) more than I was prepared to impale on the lever so I drilled & half cut thro lever and aligned it with the actuator then welded the lever up to make whole & strong again! The second issue was I selected both reverse and 1st together! In the norties when I first looked at this conversion and incorporating a J type O/D, I think it was John Kipping (by then living in NZ) responded advising to watch out and ensure I installed the washer (158585) in the reverse actuator shaft/rail as per 4 syncro Spit IV 3 rail gearbox (see Canley's MkIV gearbox drawing) or I would select both gears together. This washer is NLA by the usual suspects & I found mine ex USA, in reality it is no different to a std thin washer but I paid around $25 to buy and post to Aus, but at least I now knew what it was like! I also replaced the reverse idler (single rail) which was 21 teeth from the same US supplier. It's been a while now since I did the conversion so I hope I've got my facts right as I think Pete L says age dims the memory! Regards Peter T Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 thats good Pete but at least you were transposing a full set darrens seems a mixture ...but then it may not be is it a full set of single rail components in a 3 rail case but no mods to the reverse actuation good call Pete Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 you could be right about the hub but its made more complicated because part number 515377 listed only for Mk1 Vit was superseeded by 516911 which Rimmers show is suitable for Mk1 and 2. I think Darrens box must have all the internals of a single rail because to work it must have a 13 tooth laygear which surely has a different cut of gears and wouldnt work with the earlier main/input shaft ones. The only thing that doesnt add up is that Darren says its got the small mainshaft tip.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 think early single had the small 1/2" tip eg rkc767?? the change to 18mm tip was later on in dolly production this now has all the hallmarks of being single rail internals in the 3 rail case , so as PeterT says needs significant relay lever mods to work Pete Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 So finished work a bit earlier gone into the workshop and had a think with a good mate of mine who’s a engineer a Aston Martin ,to bounce some ideas ,pulled the main shaft out and looked at the hub to main shaft fit which is fairly snug but one question he brought up was the distances between the split thrust and the hub as shown in the two attached photos .So my question to guys is this normal ! Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 Just checked the lay shaft 13 teeth and the old idler gears is slightly tapered !! Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 As an aside I wonder if its Dolomite 1850 or Spitfire internals that have been used. As the former has the same ratios as my Vitesse that would give 26, 24, 20, 13, 15 teeth along the laygear..... Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 Thanks for all the threads l have modified the reverse selector lever as Marcus suggests heated it locally and bent it bit by bit untill it takes the back of the reverse idler gear to a few thou away from the first gear then measured and machined a new spacer sleeve which is just under a 1” that stops it touching the speed gear will check the rest of the teeth on the lay shaft a bit later Johny let you guys know Darron Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 im pretty sure the hub float is normal its a common triumph design the idler is absurd . some very odd mesh alignment to wear teeth to that angle . chimbles leading edge is one normal thing but i have never seen spur teeth wear to that dramatic extent pleased the hub is snug on the mainshaft so this sums up its a 1500 spit single rail internals in a 3 rail case to get the J type mainshaft and small tip spigot thought for the day do you need reverse !!!! Pete Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 my thought Pete is, was that idle gear in constant mesh with the syncro hub when it was in fiirst gear! because i moved the arm pivit piont back about 6mm(1/4)" and the orignal sleeve behind the gear had a extra spacer behind it, so it had to be in mesh in first, and because there is a tooth nearly missing this was making the knocking noise in first, and that the reason i took the box out ! Darron Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 Johny just checked and as yours 26,24,20.13and 15teeth on the layshaft Darron Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 19, 2019 Report Share Posted November 19, 2019 to get straight cut teeth to the angular wear there has to be something giving misalignment , under load ,, free wheeling in mesh wont wear the tooth faces like yours exhibits thats very abnormal what are the corresponding teeth like on the sleeve or layshaft this wear patern is worrying ive built a couple of spitty boxes with vitesse clusters , just need the 2nd and 3rd gears to match , makes a better ratio box in my view Pete Link to comment Share on other sites More sharing options...
johny Posted November 19, 2019 Report Share Posted November 19, 2019 just for interest then are we agreed it must be early Dolomite 1850 single rail internals built into a Spitfire 3 rail box? Link to comment Share on other sites More sharing options...
Darron Posted November 19, 2019 Author Report Share Posted November 19, 2019 To be honest Pete the other gears look good the idler gear looks like it was made like that check the photos Darron Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 20, 2019 Report Share Posted November 20, 2019 well it beats me all my years of gearbox and never seen spur gears with a tapered flank its not going to aid engagement and tooth loading is out the box for gear design whats the new one like ??? for comparison, Pete Link to comment Share on other sites More sharing options...
Darron Posted November 20, 2019 Author Report Share Posted November 20, 2019 https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/reverse-idler-gears-3x-versions.1475947/ Pete have a look at these I’m sure one is the same as the one in my box , Darron Link to comment Share on other sites More sharing options...
johny Posted November 20, 2019 Report Share Posted November 20, 2019 well the guy doesnt seem to be surprised by the one like yours but rather by the 17t non tapered one. Id say yours is definitely an attempt to improve reverse gear ease of engagement and also maybe gear whine noise.... Link to comment Share on other sites More sharing options...
Darron Posted November 20, 2019 Author Report Share Posted November 20, 2019 That’s exactly what went through my mind I think I’m heading towards taking some material off the back of the gear to allow it to go back a few thou so it doesn’t interfere With the hub it is only a reverse idler and there is plenty of material, only problem is it’s too hard to machine on a lathe will have to improvise with the lathe and a grinder ! Darron Link to comment Share on other sites More sharing options...
JumpingFrog Posted November 20, 2019 Report Share Posted November 20, 2019 To my eyes, your gearset looks like late TR7 (UKC8749 cluster), built into a 3-rail casing. But retaining a small-tip J-type main shaft (late Spitfire Mk.IV 1300?)... UKC8749 top, UKC8963 (late Dolly 1850) bottom, only difference is second gear helix angle. The part number for the 17T idler gear is UKC8750. The hub is UKC8748, you should still be able to find these parts somewhere. The Midget 1500 and Marina used these parts, Austin-Rover part number for the hub is DAM3982, these have a better made inner (forged not cast). For your reverse gear problems, it's worth checking the spacer is correct too (apologies if I haven't quite understood the issue): https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/close-ratio-spitfire-gearbox.927491.1259499/#msg-1259499 See post #55. Link to comment Share on other sites More sharing options...
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