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Darron

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Posts posted by Darron

  1. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    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 ,033478D0-7992-4110-B5BA-070B2E096818.thumb.jpeg.792fe4b8873a5ac7639e565c27dc03d8.jpegpulled 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 !

    A0FEF0AF-611B-434B-A894-294E4C358ED9.jpeg

  2. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Hi Johny

    thanks first of all for your replies ,first that’s my worry with purchasing a 33 tooth and secondly is the lay shaft gear which to be honest haven’t checked how many teeth yet , and going back to Pete’s last thread the over all length size of the the hub is surely the same so it’s not going to make any difference with the out of gear pinion problem I have with it just touching .

    when the gear box was in it drove ok all gears selected with out grinding apart from reverse obviously, as for the diff I haven’t checked but drove and pulled beautifully.

    Darron

  3. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Thank you for that Pete I will go to his site and check it out my only concern is the 17 tooth idler as there are three listed for the box 17 ,19 and 21 as long as the 17 meshes with that pitch! sorry to go on but just want it right if I’m going to lay out about  another £150 as I have paid best part of £200 with the new idler gasket and bearings , snap rings , circlips  synchros and seals at least doing it myself it will be done thoroughly and learned a lot at the same time

    Darron

  7. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    well Pete 

    the answer to that is i really dont know, the 1st and 2nd hub has 29 teeth the idler as 17 as this is another one replacing the old one which had 17 teeth , the main shaft has a small ball bearing that locates a thrust washer between 1st gear and the syncro hub, that i dont seem to find i any exploded veiw of three rail main shafts ,it has a j type OD fitted to it ,and i know from the gearbox number its a mk 4 spitfire box the end of the main shaft as the smaller roll bearing too.

    The problem is i dont know whats the difference between the the two and where to look to find out, not knowing the history of who rebuilt either other than it was done not that many miles ago but before i aquired the vehicle there is a possibility that i could get intouch with the previous owner and find out, but thats not going to really help

  8. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Hi Pete yes the tube stops the idler from hitting the first gear which I have machined a new one ,so a few thou short of touching the gear, it’s the bloody hub the problem when I took the gearbox apart the idler had some teeth partially missing and the selector was to far forward, so the gear must of been in mesh when first was selected this is why when pulling away in first it used to knock because of the partial missing teeth and the spacer tube was the right length 23.71mm but had another smaller spacer of about 2 to 3mm behind it pushing the idler even further foreword !

    I have bent the selector back into its right position as per Marcus thread but that bloody hub gear just catching the idler. I’m in two minds to grind a little off the back edge of the idler, put the original size tube back in so it clears the hub , it’s just the question why that bugs me !!

  11. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Interest Pete as I closed my browser on my phone opened it and it took a few seconds but down loaded ok so don’t know what going on there , the video is only 40 something mb it was taken on my iPhone strange . It shows the idling gear clear of the first gear but only just which is fine but when the syncro hub is engaged the idling gear catches the the hub teeth so much so that when I put the top on and select 1 st it almost locks up by hand 

    Darron 

  14. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    So after a week got back into workshop today to make a start on putting back together the gearbox ,made a dummy rear bearing and a fixture to fit to the front of the gearbox which will double up as a aid for driving on the rear bearing with a nylon bush so as to not damage the shaft tip , this was done as I was taking the main shaft in and out on a regular basis to set the reverse idling gear up ,by adjusting the selector so it doesn’t fowl the 1st and 2nd synchro hub. which worked very well , also machined up another sleeve  to just under 1”as the original was short and a extra small spacer behind it ! 
    my question to you guys is when I put the lid back on temporary and select first it still fowls the hub with it set just in front of 1st ,so took the main shaft out and there seems to be a lot of movement on the hub to shaft back and forth to where it comes up against the split thrust washers allowing it to move back a fare bit and touching the idler there is nowhere near this movement on the 3/4 hub is this normal

  17. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Well gents decided to go with the loads that the new springs give after Pete’s previous comments ,as the loads are the same . will be putting the 1st and 2nd synchro back into the box though there is some damage to the reverse gearing On this but I have had trouble sourcing another with 29 teeth I will attach a photo to see what you guys think

    Darron

    7E9C5373-6CCC-451D-AAB5-F65A48E06164.jpeg

    B4966372-06B8-42EF-A858-0080232F3F7D.jpeg

    DDABDF11-8A91-4D10-B02B-F8BAB4453174.jpeg

  19. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Ahh well Pete I would love to just use it and let you guys know but that’s a awful lot of work to put back in and then to take all out again ☹️ Bit of a stickler for things right ,that’s why I am on here with you gurus ,Going to strip them down again and really check for the allusive shims if I can’t find them then perhaps see if I can measure the old spring rates ,and use them  mix and match but with the right amount of coils , even face a bit off the old ones as Johnny as suggested some how try to get the release loads lighter fingers crossed 👍

    Darron

  23. Synchro springs 3 rail 4 syncro

    in Gearbox & Overdrive

    Posted

    Hi all

    thanks again for the post earlier in the week, going on from what Pete Lewis has 
    Enlightened me with checking the release load of the synchros on a set of bathroom scales ,the 1st and 2nd is about 15 kg (33lbs) and 3rd and 4th is 14kg (31lbs) I will add there are no shims in either synchros, my question is this too high or except-able as the manual I have says 10 to 21lbs 

    regards 

    Darron 

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