Darron

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 !

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

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

no dont be sorry Pete thats just the reasaon i ran it by you ,never noticed untill you said that it was a three syncro ! blinded by the fact i thought i found one cheap. Darron

Hi Pete do you think that this syncro hub will fit my shaft only one i can find at a resonable price at the moment. Darron https://www.ebay.co.uk/itm/triumph-herald-gearbox-cogs-synchro-rings-cluster-gt6-spitfire-vitesse/143421625485?hash=item216498548d:g:gQYAAOSwQ3JdsbdF

Thanks for the reply Pete ,hmmm so where do I go from here! I take it the hub is dimensionally the same just a different amount of teeth in which case the idler shouldn’t interfere with it any way or is it different if I source a 33 tooth hub will it mesh with the 17 tooth idler Darron

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

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 !!

Does the idling gear turn when not selected to be in reverse ,ie because the proximity of it to the hub and first gear it spins or should it be stationary, sorry for being a pain with this guys but I want to get it right and never doing a triumph box before regards Darron

Hi pete here is a photo of how close the reverse idle is to the synchro hub

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

Hi gents so back in the workshop and have made a video of the problem I have which why the box was removed in the first place any help or information would be gladly received Darron IMG_0514.MOV

Thanks for the quick response Pete that puts my mind at rest for hub float but leaves me pondering on the fact that the reverse idler still fowls because of the float bringing the hub so far back ! These things are sent to test us .

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

Don’t know to be honest but they are exactly the same as the ones I have in mine but the gearbox in mine is not the original it’s from a mk 4 spitfire I think with a j type overdrive Darron

Hi johny i am replacing the synchro rings with very good second hand ones after reading about the pattern replacements sourced a set off eBay £9.70 including postage from a 1500 gearbox but in very good nick 👍 Darron

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

Sorry Pete as you suggested not Johnny about facing some off the springs Regards Darron

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

HI Johny i had a good look and also probed at them with a pick but could not make any thing move will have to try again tomorrow and get in with a lighted magnifing glass but would of thought that one or two would have come out while i was washing and cleaning the hubs and gears Darron

hi Pete the test was slow and progressive and done several times to check, also the synchos were all lubricated up! Darron

Thanks for the quick reply Johnny ,funny thing is that before I took the gearbox out when driving it I always thought it was very stiff to put into each gear it never crunched or anything but wasn’t as slick as I thought it ought to be ! regard Darron

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

Pete thanks for all the information chap I have already made a dummy shaft for reassembly and the testing of them on bathroom scale is spot on Regards Darron

Thanks for the quick reply guys the kit came from Autogearstransmissions used these as they source better bearings and seals than Chinese ones but not labled up ! Will check rimmers diagram later regards Darron