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Rebuilding a straight cut gearbox, gears are hard to turn
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Author:  meeni [ Sun Aug 28, 2011 4:30 pm ]
Post subject:  Rebuilding a straight cut gearbox, gears are hard to turn
Hi guys, I assembled the main part of my straight cut gearbox today and noticed it feels quite tight to turn, loose a small amount back and foward but when your start rotating it constantly it's a little bit tight.. Still easy by hand, 4th and 3rd gear are quite free, but 1st and second gear are very tight.. This to me feels wrong.. But maybe it's something that needs to bed in? I'm not 100% sure,, reverse gear is almost impossible to move by hand also,, bit worried as I don't want to damage 1000 dollars worth of gears.. So if anyone has expierienced this and knows what's wrong of If it's normal then please let me know asap

cheers

sean
Author:  GT mowog [ Sun Aug 28, 2011 5:43 pm ]
Post subject:  Re: Rebuilding a straight cut gearbox, gears are hard to tur
meeni wrote:
.....But maybe it's something that needs to bed in?


There is nothing in a Gearbox that 'beds in' only parts that wear out. Something is wrong with it.
Author:  meeni [ Sun Aug 28, 2011 5:45 pm ]
Post subject: 
Had to ask the question... Got any ideas why it's tight?
Author:  simon k [ Sun Aug 28, 2011 6:18 pm ]
Post subject: 
take it all apart again and start from scratch
Author:  low n blown [ Sun Aug 28, 2011 6:37 pm ]
Post subject: 
Check the parts you are puttin in are true. I have recently seen lots of new parts for gearboxes that are totally crap, synchros, layshafts. Also check the bearings (motion shaft) are sittin home fully and evenly all round. But especially check the layshaft is not bent. Something is up for sure.

PS it can bind a little if the nuts on the final drive and input shaft are not fully torqued, so I just found out last week.
Author:  meeni [ Sun Aug 28, 2011 7:17 pm ]
Post subject: 
I've pulled it apart and put it back together 3 times now and it all seems to be in good order, I can't feel a single part as the culprit as it all spins freely until you fit the lot together, neither of the input shaft nuts are tight so that may not be helping, I put a breaker bar on the input shaft nut and went through the gears turning it from there, they all spin and are even feeling throughout the cog, just reverse is tight, and when I say tight I mean with a 1/2" breaker bar on I can turn it without too much effort, then first is a little better, second a little better, then neautral is 3rd best, then 3rd and 4th are easy to turn regardless. I put a little oil on the gears to se if that helped and it did slightly as they were completely dry, I honestly can't think of any reason for it to be not working.. Maybe it is and I'm making I sound bad...
Author:  Asphalt [ Sun Aug 28, 2011 7:28 pm ]
Post subject: 
Did you use new 'genuine Rover' baulk rings...?

So basically you can't spin gears & mainshaft in opposite direction ('reverse')? I had this symptom when I first used 4 genuine Rover baulk rings. With 4 good used ones it all span free like it should. On the latest gearbox I've used a Rover ring on 2nd gear, and 3 MiniSpares rings on 1st,3rd & 4th. Which worked too. On my own gearboxes I use good 2nd hand rings (3rd & 4th are not that worn in most cases anyway).

However, I wasn't able to figure out what the problem is/was with those baulk rings... They'r not too big. I suspect the inner shape could be wrong and the new ring can't travell far enough on the cone and 'binds' the gears/synchro hubs. That's all theory of course and I could be wrong. However, there was definately a problem with 4 Rover rings. And I'm open to suggestions of what the problem might be :)

Cheers,
Jan
Author:  meeni [ Sun Aug 28, 2011 7:37 pm ]
Post subject: 
im using the baulk rings provided by guessworks from whom i bought everything.. theyre specialty is gearboxes so surely they dont sell the crapola ones.. hmmm interesting
Author:  GT mowog [ Sun Aug 28, 2011 7:49 pm ]
Post subject: 
What type (cast no. please) of gearcase are you fitting them in to and what's it's history?
Author:  meeni [ Sun Aug 28, 2011 8:06 pm ]
Post subject: 
havnt got a cast no handy at the moment but its a late a+ type gearbox and history is unknown as its from the uk and i bought it on friday..
Author:  meeni [ Sun Aug 28, 2011 8:23 pm ]
Post subject: 
heres the casing..

Image

and heres where im at with the gears, anything obviously wrong there?

Image
Author:  Harley [ Sun Aug 28, 2011 8:27 pm ]
Post subject: 
I'd take it apart and it back together without the oil pickup, selector forks, etc and see how that is. If its the same, remove the second layshaft and see how things feel then.

Have you got the original gearset still as a reference for measuring, just incase anything hasn't been made to tolerance?
Author:  GT mowog [ Sun Aug 28, 2011 8:37 pm ]
Post subject: 
From the what I can see in your pic it 'looks' OK, but it's not the same as having it on the bench in front of you.

Harley wrote:
I'd take it apart and it back together without the oil pickup, selector forks, etc and see how that is. If its the same, remove the second layshaft and see how things feel then.


I was thinking something similar, only leave the baulk rings out and nipping up the first & third motion shaft nuts, just the seat the bearings 100%.

But, before you strip it down again, while in 1st or 2nd and you spin it over, have a look at the 'ears' of the baulk rings in 3rd and 4th, you'll see them in the synchro hub, one of these may be picking up. You should easily be able to move them with a small screw driver, freely.

When (as I guess you will have to) strip it down again, you'll be removing the laygear before the 1st & 3rd motion shafts. At this point make sure the 1st and 3rd motion shafts spin freely of each other and test that all other gears (1st, 2nd & 3rd) also spin freely. There should be no binding what so ever.

Asphalt wrote:
Did you use new 'genuine Rover' baulk rings...?

So basically you can't spin gears & mainshaft in opposite direction ('reverse')? I had this symptom when I first used 4 genuine Rover baulk rings. With 4 good used ones it all span free like it should. On the latest gearbox I've used a Rover ring on 2nd gear, and 3 MiniSpares rings on 1st,3rd & 4th. Which worked too. On my own gearboxes I use good 2nd hand rings (3rd & 4th are not that worn in most cases anyway).

However, I wasn't able to figure out what the problem is/was with those baulk rings... They'r not too big. I suspect the inner shape could be wrong and the new ring can't travell far enough on the cone and 'binds' the gears/synchro hubs. That's all theory of course and I could be wrong. However, there was definately a problem with 4 Rover rings. And I'm open to suggestions of what the problem might be :)

Cheers,
Jan


The Baulk Rings Guessworks supply are non-genuine.
Author:  TheMiniMan [ Sun Aug 28, 2011 9:22 pm ]
Post subject: 
If you havn`t done up the big pinion nut, then you havn`t clearanced the gears from the syncros properly

it`s probably jst grabbing -dragging syncros,,,typical when you havn`t pulled the mainshaft up to the pinion end,,,

tighten your big nuts & have another feel

seems a bit kinky i know :-)
Author:  lmbm [ Mon Aug 29, 2011 4:23 am ]
Post subject: 
Quote:
If you havn`t done up the big pinion nut, then you havn`t clearanced the gears from the syncros properly

it`s probably jst grabbing -dragging syncros,,,typical when you havn`t pulled the mainshaft up to the pinion end,,,

tighten your big nuts & have another feel


when i built my first box it was feeling tight also.. and once all was torqued up then it went just fine.

One other thing to be aware, the inner part of the 1st/2nd synchro hub can be fitted wrong way :x , the face with an edge/ring around the shaft bore needs to be fitted towards first gear.

Cheers
Luis
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