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Gearbox thrust washer
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17-12-2018, 07:49 PM
This might result in an embarrassing admission but can someone tell me if the flat steel bit flush with the synchro cone here is the splined thrust washer that goes between the 1st and 2nd gears on the main shaft? This is from a 4 speed 2 synchro gearbox.
Thanks! Simon 
17-12-2018, 08:39 PM
Ready to be corrected (I admit it's too cold to go out and find one to fiddle with!) but I think that's right Simon.
Dare I ask where this is leading? If it's any consolation I haven't yet found a way that a 4-Speed box can be assembled incorrectly...
17-12-2018, 09:38 PM
It's been so long since I dismantled it now that it's going back together I can't remember if there was a separate washer there or not. For some reason I was thinking I had lost it, having some vague memory (imagined from pictures in parts books I think) of seeing it off the shaft. Now I am reassembling I couldn't find it anywhere.
I've been looking everywhere at home, pulling out all the boxes of parts, looking through plastic containers full of random screws and bolts and washers in a desperate attempt to find the 'missing' part. When I dismantled it I even took photos of all the parts but none of them showed the missing washer. That should have been my hint. I think it's part of that assembly. I never actually removed it so it's not been lost at all! That is if that's what I am looking at in that picture. So I spent the last two weeks looking frantically for something that was right in front of me the whole time... Simon
19-12-2018, 03:49 AM
I decided that must be it and since the end float between 2/3 is in spec I am going to leave it alone for now and start to reassemble the box. Will see how it all goes together.
Simon
19-12-2018, 01:20 PM
I think there's sometimes a stronger case for leaving things alone than for having them apart.
19-12-2018, 02:08 PM
Probably the case with a 4 speed crash - they seem to be the strongest and most reliable. Not so with the later synchro boxes. I bought a second hand 4 speed synchro box thinking that it would be an upgrade but it was knackered. Apart from the layshaft bushes being made from unobtainium the teeth on the 3rd/4th selector cones had been ripped off, there was considerable wear in the intershaft bearing and the selector forks were also badly worn. It looked like it had been full of water at some stage and overall it would have made a decent boat anchor but nothing more.
19-12-2018, 02:27 PM
(19-12-2018, 02:08 PM)Reckless Rat Wrote: Probably the case with a 4 speed crash - they seem to be the strongest and most reliable. Not so with the later synchro boxes. I bought a second hand 4 speed synchro box thinking that it would be an upgrade but it was knackered. Apart from the layshaft bushes being made from unobtainium the teeth on the 3rd/4th selector cones had been ripped off, there was considerable wear in the intershaft bearing and the selector forks were also badly worn. It looked like it had been full of water at some stage and overall it would have made a decent boat anchor but nothing more. I completely agree Reckless that synchro boxes are more delicate - that's one of the reasons I now have a 4-crash in mine (£7.50 well spent!) When it comes to an entire box I would never take a chance on running one without a strip down - not unless I knew it had come straight from a working car. In Simon's case there's a limit I think to how much evil may be lurking between his 2nd and 3rd cogs. When I rebuilt my synchro box (long time ago now) I ground a thou or two off the layshaft to clean it up (they are quite deeply hardened) and had new bronze bushes turned up to suit. Nothing fancy and they weren't line bored either but it was still running fine a couple of decades later. The synchro parts seem the most difficult area to me as I don't know what you can do (at reasonable cost) other than juggle them from one box to another.
19-12-2018, 08:48 PM
I got the gears in last night then found it had all locked up. I ended up re-shimming under the layshaft bush and very carefully selecting the right paper gasket thickness and testing it all with the layshaft bolted in properly. That's where I had gone wrong, my initial attempts were based on measuring with things not done up fully. It's surprising how much things change when done up tight. I got the layshaft endfloat to 4 thou in the end.
I also had one of those SPROINGGGGGG! moments when I pushed the 1/2nd gear synchro a tad too far and everything came apart. I found to get the gears in you need the 1/2nd synchro in the second gear engaged position. Luckily I found all the balls so no harm done. After that it all went together pretty easily with a bit of heat from the heat gun. The selectors aren't in yet (tonights job) but it all looks good so far. I enjoy seeing how something like this goes together and understanding how it all works. I put tape on the input and output shafts so I could see how the ratios change. Especially things like seeing why you shouldn't ever drive with your hand resting on the lever. It's good to be told things like that but even better to see and understand why yourself.
20-12-2018, 07:29 PM
Last night I looked at installing the selectors. I installed them loosely, without balls and springs, just to check I had everything put together correctly and yes, I can see it is all working properly. I was wondering if you should build up with bronze then file back the selector arms but wear on those didn't seem to make much difference, the bigger factor for how much the gear stick wobbles is seemingly the arms on the interlock plate.
I was looking at how you get the balls and springs in and tried one and gave the shaft a tap with the hammer. Nothing moved. Gave a bigger tap. Slight movement. Gave an even bigger tap and again SPROINGGGGGG! 1st speed synchro moved to far and springs and balls everywhere again (inside the box of course so none lost). I can see why people don't like fiddling with gearboxes! All apart again. I can pull the thing apart now in 5 minutes or so. So that all redone and all back together. That I can also do pretty quickly now I know how to do the fandango to get it all back together (I took pics I will put on my web site later). I decided to make the little tool shown in the Woodrow book but instead of metal I have modelled up and 3D printed some. No idea of that will work. I don't see why not. Will try that tonight. Simon |
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