Lotus Elan

hard to shift after new synchro hub

PostPost by: mini64 » Mon Feb 08, 2016 4:32 am

I replaced my 1/2 synchro hub assembly (and rings and blocker bars) due to grinding going into second (gears are relatively new). Grind is gone but it is very hard to get into either first or second, moving or stationary. Any ideas what I might have done wrong?
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PostPost by: Elan45 » Tue Feb 09, 2016 3:24 pm

I'm wondering if you've not got the interlock plungers wrong in the front end of the box. These go between the shift rails and interact through the plunger that fits in the center rail.

There is also an exact order the semi-circular springs and blocker bars go into the hub and supposedly there are match marks on the syncro hub and outer ring. I've always tried to put every thing back in order, but never had a hard shift problem as you describe.

On old BMC boxes such as Sprite, there is a plunger inside the hub which must be fitted exactly or it won't work at all, but I don't remember any such device in the Ford box. Sorry, I am down south and have no actual components I can hold in my hand to jog memory.

There is always the issue of different parts for early/ later boxes. Are you sure this is the right hub assembly for your gearbox?

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'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
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PostPost by: rgh0 » Wed Feb 10, 2016 10:03 am

If it was crunching before and now is hard to engage gears after replacing the synchro hubs and blocker bars it could be due your clutch dragging and not fully disengaging.

Before with worn synchros you could push through the blocker bars and engage before the speeds were synchronised producing the crunch. Now with new components the blocker bars are doing their job properly and stopping engagement when the speeds are mismatched making it difficult to engage gear.

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PostPost by: weddingcarclive » Wed Feb 10, 2016 10:36 am

have you used correct gear oil? Too thick and it will give these symptoms !!!
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PostPost by: mini64 » Wed Feb 10, 2016 6:50 pm

thanks for the responses guys.

it is just as hard with the engine off so I don't think its clutch problems. I'm using the same oil I always use - redline mtl 75-80

I do worry about the interlock plungers but this isn't my first time to mess with those. However, since I wasn't doing a full cleaning and rebuild this time I decided to try a new trick - as I pulled the shift rods out the back I chased them in with a bolt from the front, the bolt keeping the two larger plungers from falling out. This seemed to work well, but did it? I did get the center pin in.

It always takes me a few tries to get the blocker bars and wire springs to stay in as I am assembling but I try to check them and put them in the correct direction.

Roger, Interesting to note the word "supposedly" when referring to the match marks as I have never found any marks in my box. Yet this is probably the 5th time I've had it apart and never a previous problem like this.

I hope I have the right hub assembly - I ordered the late model which my box is and dimensionally it appeared the same.
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PostPost by: gus » Thu Feb 11, 2016 2:17 pm

So 3/4 is fine?

how does it feel?

I mean, the elan gearbox has a pretty light touch.
In the 3/4 you should feel the little play between the shift lever and the rod, then the little play between the fork and hub etc.
Does 1/2 feel the same?

try taking the shifter out and moving the rods with a screwdriver, do they move equally easy or is the 1/2 tight?

the interlocks just keep you from moving both shift rods at the same time, I would think they either work or they don't, unless some crap got in there, but I would think that would hardly be noticeable

If it isn't something dumb like the shifter ball cranked down too tight or a bit of snot in the shift rod, out she must come unfortunately
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