joinathanbrooks Posted March 15, 2021 Report Share Posted March 15, 2021 Refitting a gearbox with with A type overdrive (no overdrive previously) into car. Got so far as have engagement on splines/clutch plate as cannot turn rear drive flange on gearbox. I could before and box is in 4th gear. Using gap between Engine and bell housing estimate approx. 8 mm to go and box will not go home. Slides nicely although hard "donk" before coming to a hard stop. Any pointers/assistance welcome. Quote Link to post Share on other sites
PodOne Posted March 15, 2021 Report Share Posted March 15, 2021 Hi Jonathon? Have you replaced the spigot bush in the end of the crank? Might be worth just checking its internal diameter v the end of the input shaft. Has the input shaft any slight "nicks" that might be just enough to stop it going home. Not bent one of the top three studs which might be stopping it going together. Is the clutch plate the right way around as one side is more prominent and from memory should face the flywheel? Although I'm not sure if this would stop it mating. Andy Best of luck. Keep us posted sounds like it will be something simple. Quote Link to post Share on other sites
rcreweread Posted March 16, 2021 Report Share Posted March 16, 2021 Jonathan - if gearbox splines have engaged with the clutch plate and you have it in 4th gear, it won't turn, as to do so would mean turning over the engine! Knock it out of gear and the it should then turn Cheers Rich Quote Link to post Share on other sites
Bfg Posted March 16, 2021 Report Share Posted March 16, 2021 I've experienced similar when fitting a gearbox to an engine (not a Triumph though). Silly me.. a dowel had fallen out and I put it into the wrong hole ..and then there were two ! ..one dowel sticking out of the engine case and one sticking out of the bellhousing. Definitely one of my more greying-blonde moments ! Anonymous Quote Link to post Share on other sites
joinathanbrooks Posted March 16, 2021 Author Report Share Posted March 16, 2021 Expectation is that it will not turn as connected to Engine through the clutch. Checked and there are no dowels/studs as all were removed. Wondering if clutch out of line/clutch plate wrong way round/something else; any suggestions/experiences? Quote Link to post Share on other sites
John L Posted March 16, 2021 Report Share Posted March 16, 2021 You may have a different gearbox input shaft, can you give us a picture of the one you took out? I had this problem, but did notice, as tried plate on the gearbox shaft first. John Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 Should the bearing that the gearbox input shafts goes into; move backwards and forwards? Quote Link to post Share on other sites
PodOne Posted March 17, 2021 Report Share Posted March 17, 2021 14 minutes ago, joinathanbrooks said: Should the bearing that the gearbox input shafts goes into; move backwards and forwards? Presume you mean the spigot bush in the flywheel then no. Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 58 minutes ago, PodOne said: Presume you mean the spigot bush in the flywheel then no. yes the spigot bush and moves by approx. 4mm. Is there a difference between TR5 and TR6 spigot bush? Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 Have you replaced the clutch? Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 yes clutch has been replaced and checked plate was the correct way round Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 Sounds like you are out of alignment if you did not change the spigot bush it should be fine Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 yes probably out of line after checking today; although do not know why spigot bush would move laterally (backwards and forwards). Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 They do but not side to side Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 so normal for spigot bush to move back and forward in the region of 4 mm? Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 Yes the only difference in size is between the long back crank and short and if you did not change it then alignment it is Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 What is the the long back crank and short? Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 do these two different cranks have a different size spigot bush? Quote Link to post Share on other sites
PodOne Posted March 17, 2021 Report Share Posted March 17, 2021 First Jonathon what year car is yours? The early cars 1969 I believe had the long backed crank the same as the TR5 with the spigot bush in the rear of the crank and the later cars with the short back crank the spigot bush fits in the rear of the fly wheel and yes they were different sizes listed by Rimmers https://rimmerbros.com/Item--i-GRID600006. I'm not sure when the crank change over happed someone will no doubt chip in. When I fitted the clutch to my 1969 long back crank the bush was flush with the rear of the crank and I could not get any rear/forward or rotation movement and the input shaft slid straight in first time so I presume and makes sense that the input shafts nose spins within the internal diameter of the bush which is a press fit within the crank same principle I suspect with the other option of the spigot bush in the flywheel. Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 My car was registered May 72. Spigot bearing is in crank and I replaced that some 25 years ago when original rebuild done as I have old spigot bearing. Noticed also flywheel crank mount bolts have wear on them possibly caused by clutch plate splines on the input shaft. Borrowed a TR6 input shaft tonight to align clutch plate for refit. Spigot end of this fits old bearing (this is worn) but not the one in the crank, that may be a red herring. I do recall from a conversation many years ago that my crank is "cross drilled" although cannot remember the context that comment was made in. Just been reading and noted that long/short cranks have to have flywheels that match and do not understand the implications of that at present. Originally clutch assembly and bearing replaced during rebuild. Quote Link to post Share on other sites
PodOne Posted March 17, 2021 Report Share Posted March 17, 2021 Struggling to visualise why the flywheel bolt heads would have wear on them doesn't sound right and if the input shaft fits the old and not the new it suggest the new bush internal diameter is too small (Wrong bush?). Might be time for some pictures? Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 The flywheel on the long back is dished to allow for the long crank and the spigot fitted to both is in the crank.Have you removed the clutch to check the fit? Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 Pic attached. Quote Link to post Share on other sites
joinathanbrooks Posted March 17, 2021 Author Report Share Posted March 17, 2021 What do I need to check the fit of? Quote Link to post Share on other sites
ntc Posted March 17, 2021 Report Share Posted March 17, 2021 Is the pic how it is now? Quote Link to post Share on other sites
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