Jumping out of second gear
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alexander
- Posts: 139
- Joined: Wed Nov 14, 2018 2:10 pm
- Your interest in the forum: Javelin 1953 That has been off the road for a number of years needing some TLC. Also have a 1959 TR3a and a Francis Barnett 1951Merlin.
- Given Name: Dave
- Location: Warwick
Jumping out of second gear
Suggestions please drove the Javelin today and for the first time , when changing into second gear it jumps back out a couple of times. Could this be adjustment of the two little pegs and springs on the gearbox .
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JUP
- Posts: 26
- Joined: Sun Nov 21, 2021 9:45 am
- Your interest in the forum: Own Jowetts
- Given Name: Graham
- Location: Shropshire
Re: Jumping out of second gear
Suggest you check the gear rods length first - if this is the cause it will only need a little adjustment
I always set the rod length by puting the gearbox in reverse and adjust the gear rods accordingly
I always set the rod length by puting the gearbox in reverse and adjust the gear rods accordingly
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David Morris
- Posts: 837
- Joined: Thu Feb 09, 2006 9:23 am
- Your interest in the forum: Jowett Javelins since 1964. Now a Jowett Stationary engine owner and club member since 1964.
- Given Name: David
- Location: Sunny Bristol
Re: Jumping out of second gear
Hi Alexander,
There are several methods of setting the lengths of the rods. I suggest you first try the Jowett method set out in the handbook. You will need to find a small twist drill, to hold the selector shaft in the correct position. There is a corresponding hole in the gearbox casing. This locks the selector shaft in the correct position, and you can then set the rod lengths.
Bear in mind though that's with a new gearbox. You have one that's 70 years old, and you may need to apply a bit of tolerance. Personally, I would leave the selector rod detent adjustments alone, until you have tried the rod lengths. Whatever you do, make small adjustments at a time.The whole gearbox is a collection of worn components, and hitting the 'sweet spot', is tricky. I once knew an ex-Jowett Technical Apprentice, who spent months just lapping components on the Jowett-manufactured gearboxes, trying to get them to work. He ended up with a skin condition, that he was sure had been caused with his hands immersed in gearbox oil for months. Your box might have been one of his?
All the best,
David
There are several methods of setting the lengths of the rods. I suggest you first try the Jowett method set out in the handbook. You will need to find a small twist drill, to hold the selector shaft in the correct position. There is a corresponding hole in the gearbox casing. This locks the selector shaft in the correct position, and you can then set the rod lengths.
Bear in mind though that's with a new gearbox. You have one that's 70 years old, and you may need to apply a bit of tolerance. Personally, I would leave the selector rod detent adjustments alone, until you have tried the rod lengths. Whatever you do, make small adjustments at a time.The whole gearbox is a collection of worn components, and hitting the 'sweet spot', is tricky. I once knew an ex-Jowett Technical Apprentice, who spent months just lapping components on the Jowett-manufactured gearboxes, trying to get them to work. He ended up with a skin condition, that he was sure had been caused with his hands immersed in gearbox oil for months. Your box might have been one of his?
All the best,
David