If you would like to join the DLOC, please visit the Club's website https://www.dloc.org.uk/
Please don't post someone's email address. Some people don't want to risk it being harvested by spambots and GDPR regulations discourage it.
Always look at "ACTIVE TOPICS" which gives all posts in date & time order if you can't find a post or "Your Posts", as topics are sometimes moved.
Reg. nrs. Please add reg. nr. when posting a photo or anything about a car as this will help searches. Don't add punctuation next to nr. as this negates search.
FORUM DOWNTIME 22/06/19 , please read this topic: viewtopic.php?f=16&t=4577 There are missing posts. Please post again.

Pre-select adjustment N. Wales

Post Reply
BigJAK
Posts: 34
Joined: Mon Dec 18, 2017 10:00 pm
Location: North Wales

Pre-select adjustment N. Wales

Post by BigJAK » Wed Dec 26, 2018 8:03 pm

Hi,
I have a 1956 CC with a preselect box and have tried to adjust the first rod but think I have made it worse.
I read the instructions online and asked about being able to feel detents on the gearbox end and March them to the positions on the selector but as I said think I have made it worse.
Is there anyone in North Wales that could come and help?
Thanks

Stan Thomas
Posts: 504
Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Pre-select adjustment N. Wales

Post by Stan Thomas » Thu Dec 27, 2018 7:06 am

There are no detents in the gearbox selector mechanism.

I think the best thing to do is give me a ring on 01785 713862 - and I'll talk you through the adjustment.

qantasqf1
Posts: 110
Joined: Mon Mar 07, 2016 10:13 pm

Re: Pre-select adjustment N. Wales

Post by qantasqf1 » Thu Dec 27, 2018 6:14 pm

Just for the record and as an academic point there is a detent mechanism in these gearboxes. The struts each feature a rectangular lug which has to pass through a narrow slot machined into the brake gear mechanism. The gap between each slot had a plunger that moves to the left or right depending on which gear has been selected, thus preventing any other strut to pass through. It’s a very simple and effective arrangement, but there is no setting or adjustment for them...what you see is what you get. Just saying.
Steve

Stan Thomas
Posts: 504
Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Pre-select adjustment N. Wales

Post by Stan Thomas » Fri Dec 28, 2018 8:26 am

I'm afraid you've got it wrong Steve, and have confused the "double selection" protection mechanism as an detent.

To avoid the possibility of selecting two gears at once, there is the mechanism you describe - whereas, a detent mechanism (not present) would otherwise be to give a positive location of each gear as selected.

The external selector arm turns a skew gear which activates a camshaft which in turn advances and retracts the gear struts to the bus-bar face for selection and de-selection - and it is these struts which are subject to the safety mechanism you describe - but they do not locate or positvely identify the gear positions in respect of manually adjusting the external gear linkage as per BigJAK's inquiry - or indeed any of the various model gearboxes I've overhauled during the past 50 years or so.

https://www.merriam-webster.com/dictionary/detent
Last edited by Stan Thomas on Fri Dec 28, 2018 8:48 am, edited 2 times in total.

qantasqf1
Posts: 110
Joined: Mon Mar 07, 2016 10:13 pm

Re: Pre-select adjustment N. Wales

Post by qantasqf1 » Fri Dec 28, 2018 8:45 am

I thought a detent was a mechanism that prevented an action unless allowed to. Semantics, I suppose.

Post Reply