johny

I take it if the bush is shorter than the gear theres a risk it will spin on the shaft with the gear rather than just the gear spinning on the bush as per design....

Could use a micrometer on the bushes at least to see if their length is within tolerance....

I dont know Pete, according to the manual each bush should be slightly longer that the gear it fits in. With care this should be measureable and if not present the set up once on the shaft is never going to be right🙁

If youre sure of the measurements (the end float is only 0.051 - 0.152mm) looks like you need new bushes. Rimmers have 147354 and I THINK theyre the same for all models of gearbox or perhaps you could use the ones in the other gearbox?

well I suppose the proof is in how well it 'bites' onto a cone so you could try that manually but Id be surprised if it wasnt perfectly useable. Also just noticed that the damage is on the part of the ring that will come into use very late on, if ever, in its life as its on the trailing edge of the grooves so another reason for it being nothing to worry about👍

before you start Daniel you could check the thickness of the new thrusts as Rimmers say they should be the same as the manual indicates which is: 1.676 - 1.727mm small washer 3.124 - 3.175mm large washer

Measure the thickness of the old rollers with a micrometer and pick out the two biggest ones (you can compare their size with the new ones)... I dont like the look of either of the old thrust washers as they have done quite a few kilometers so think it best to take some metal off the back of the bigger of the new ones. This shouldnt be too difficult as the steel is soft and you can use a piece of emery cloth (abrasive sheet) held on a flat surface and carefully rub the thrust washer on it. Measure its thickness all the way round to make sure youre doing it evenly and obviously stop when youve reached the correct size - measure the gap from laygear to case with feeler gauges to calculate this👍

should be 25 rollers each side. New thrusts look ok although looks like the design is slightly different for the smaller one but the part that takes the load is the same size👍 The manual says to set the laygear end float by selecting the correct thrust washers to give between 0.178 and 0.330 mm clearance. If your outside of this you could remove metal from the back of a washer or if loose make a shim....

Oh but a word of advice though, be careful when pulling the magnetic trigger wheel off the dizzy shaft as its plastic top can come away from the body which allows the incredibly small but powerful magnets inside to fly out and attach themselves to each other or any metalwork! Its then a horrendously fiddly job to get them back into the body and of course they all have to be installed north-south pole correctly or wont operate the sensor head🤪

Not to mention different size synchro rings in the same box😂

Yes I like the accuspark (and under various other names) variety now that they seem to have sorted out the early failure problem. However I do still think its a good idea to buy a second kit, which can be any Amazon 20 pound jobbie, so that in case of a problem you can quickly swop over just the head unit. This needs a small allen key to do but has the advantage of leaving the backplate in place so the timing stays the same👍

Although this 150328 offering from Bastuck in Germany at 14.46€ (incl VAT) might be a good alternative....

Yes Im still waiting for a report back on how well these pattern part synchro rings work from someone who has rebuilt a gearbox with them? I suspect NOS or even good used originals are preferable but for Daniel in Germany thats not going to be easy....

The good news is that all the other components in your overhaul kit should be good for the later gearbox👍

Well you cannot be 100% sure because gearboxes have been modified over the years (the later bigger synchro rings last longer and work better then the originals) but yes youre right the KD should have the smaller rings the same as in the kit. The rings are common to various Triumph (and other makes) models with the small ones being used in all Heralds, Spitfire 1, 2, 3, Vitesse 1 & 2 and GT6 1, 2, 2+ while the larger were in GT6 III, Spitfire IV & 1500 (single rail) plus other models....

One thing, the three rail gearbox used two different designs of synchro ring during its life. The early ones are part number 148409 and they have a smaller internal diameter than the later synchros 150328 so are not interchangeable. Your car would have used the early type while the later Mk3 GT6 (KE serial number gearboxes) had the bigger ones which would explain why the new rings you have wont fit on the cones...

without load there should be minimal contact so the tip bearing being a needle roller should be ok. However if towed for a long distance Id be more worried about the stationary gear sleeves running dry and seizing on the spinning mainshaft....

I think even though the lube in a towed gearbox isnt as designed it doesnt usually cause a problem because the components arent under load😊

yes the only remedy I can see is to wedge the clutch pedal down and put the gearbox in 4th gear. That would ensure everthing is spinning in the gearbox and more closely replicate the normal driving situation but of course could lead to disaster😨

Well its actually a bit different to drive our gearboxes from the prop end because although its true the mainshaft will spin there will be limited splash lubrication as none of the forward gears on it will turn. They are held stationary along with the input shaft and laygear so there could be a lack of lubrication especially for the tip bearing and gear sleeves...

Strange that the compression is good though. I suppose one of those leak down tests where you pressurise each cylinder stationary and then see if it drops would be more useful?

Ha, Im surprised the Fiats tyres didnt slide until they burst! Must have been some big ol RV not to notice the extra drag🤪

You know the Triumph workshop manual for the TR7 is available online for free download?

I think a lot of it is the condition of the block hole - if theres any corrosion or damage to it then getting the plug to seal is always going to be harder. Ive never used the disc type plug but they look even riskier...

Oh I dont know, this is what Rimmers show they supply for all single line MC GT6 models (pt number 517662)...