[928uk] 3 speed gear change rpm

[todd at oxfordeye.co.uk]

Hi Smiffy, 

 

Mine is a 1979 car, so I don’t think it has a kickdown relay? But… I made a temp fix to shorten the Bowden cable and it now changes at 4500rpm AND it kicks down. I just need to make a better fix (aka properly) and adjust the locking bolt on the throttle pressure thing (side of gearbox that the Bowden cables connects to)

 

Thanks,

Todd.

 

From: Paul R Smith <smiffypr at gmail.com> 
Sent: Wednesday, June 5, 2024 9:39 AM
To: todd at oxfordeye.co.uk; 928uk at lists.928.org.uk
Subject: Re: [928uk] 3 speed gear change rpm

 

The next test along this line of investigation is, repeat test with ignition on, can you here a relay click when your pedal operates the switch. You may need to expose the fuse-board to hear it.

Smiffy

On 04/06/2024 21:33, todd at oxfordeye.co.uk <mailto:todd at oxfordeye.co.uk>  wrote:

Hi Smiffy, 
 
Yes, I hear the click - tested and it does not kick down though. That’s a problem for future Todd.
 
Todd.
 
-----Original Message-----
From: 928uk  <mailto:928uk-bounces at lists.928.org.uk> <928uk-bounces at lists.928.org.uk> On Behalf Of Paul R Smith via 928uk
Sent: Tuesday, June 4, 2024 9:15 AM
To: 928uk at lists.928.org.uk <mailto:928uk at lists.928.org.uk> 
Subject: Re: [928uk] 3 speed gear change rpm
 
When you push the pedal the last few mm to the floor (engine/ignition off), can you hear the kickdown switch click?
 
Smiffy
 
On 04/06/2024 07:25, toddgibbs111--- via 928uk wrote:

Hi Llew,
 
So, throttle is sharper, zero play. Perhaps a little too tight as I noticed the idle siting at 1100 (I think cable is keeping it open slightly).
 
Anyway, gear changes at 4100 rpm still.... I'll get under the car today and see what I can find.
 
Todd.
 
-----Original Message-----
From: Llewelyn Guildford <mailto:llew.guild at gmail.com> <llew.guild at gmail.com>
Sent: Monday, June 3, 2024 4:50 PM
To: Todd Gibbs <mailto:todd at oxfordeye.co.uk> <todd at oxfordeye.co.uk>
Cc: 928 <mailto:928uk at lists.928.org.uk> <928uk at lists.928.org.uk>
Subject: Re: [928uk] 3 speed gear change rpm
 
Hi Todd
 
No worries, I’ve been there myself with a lot of what you’re doing so it’s quite relaxing viewing from the sidelines!
 
Can you send a photo?
 
Let me know what it is like with the throttle cable adjusted , you might find it sorts itself out because the throttle actuator is what pulls on the gearbox shift cable and if it’s too slack it won’t work properly! The gearbox cable is definitely adjustable though, sorry I can’t explain the exact steps.
 
Llew
 
Sent from my iPhone
 

On 3 Jun 2024, at 16:09, Todd Gibbs via 928uk <mailto:928uk at lists.928.org.uk> <928uk at lists.928.org.uk>  wrote:
 
Hi Llewelyn
 
Thanks for watch the videos :)
 
Ok I’ve had the airbox off again today and there is no adjustment there in mine. I know exactly where you are thinking (there is a hard tube rising from the bell housing that thur cable passes through). Mine just has a flexible cable “shield” that connects to the hard pipe.
 
I’ve gone back and adjusted the throttle cable, it was slightly loose, and about to test it out….
 
Thanks and will report back
 
Todd
 

On 3 Jun 2024, at 09:42, Llewelyn Guildford <mailto:l.guildford at stemmer-imaging.com> <l.guildford at stemmer-imaging.com>  wrote:
 
Hi Todd
 
I follow your project on YT - Great progress 😊
 
It's a while since I've done this (2017 I think!) so hopefully my memory serves me semi-well!
 
The cable is adjustable - Although the adjuster doesn't look obviously so. It seems hard to find an image of it online. The adjuster isn't as an end of the cable, it is half way down. It is located slightly right of centre if you're looking from the front of the car, and is situated behind the airbox on or near the bell housing, so if you take off your airbox and look down behind the bulkhead, standing on the left hand side of the car you should be able to see it. I can't remember in detail exactly how to tension it but it is fairly obvious.
 
Check list for correct shifting:
 
Make sure the kickdown switch is working, is adjusted correctly and 
that the throttle pedal actuates it at WOT (all this can be done
stationary) Make sure the gearbox has the right level of oil in it and that the oil is in reasonable condition I've personally never had to mess around with the vacuum modulator thing on the gearbox and I've had quite a few 3 speed 928s.
 
Then move on to the cables
 
Start with the throttle cable and get it tensioned so it's nice and tight but doesn't bind! Once you're happy with that adjust the elusive Bowden cable and you should be good to go.
 
Gearbox side I would a) not mess with the vac modulator other than 
to make sure there are no vacuum leaks b) whatever you've altered on 
the cable mount bolt I'd put it back to the original position
 
9 times out of 10 gearboxes run perfectly after this.
 
When you've got a baseline result you can then drive, make a small adjustment to the Bowden cable either way then compare - You'll find your own sweet spot with it!
 
If you need a hand ever I do find myself in Oxford from time to time so could pop over and have a look with you...
 
Hope this helps,
 
Llewelyn
 
-----Original Message-----
From: 928uk <mailto:928uk-bounces at lists.928.org.uk> <928uk-bounces at lists.928.org.uk>  On Behalf Of Ben Hodges 
via 928uk
Sent: Sunday, June 2, 2024 7:12 PM
To: Todd Gibbs <mailto:todd at oxfordeye.co.uk> <todd at oxfordeye.co.uk>
Cc: 928 List <mailto:928uk at lists.928.org.uk> <928uk at lists.928.org.uk>
Subject: Re: [928uk] 3 speed gear change rpm
 
Hi Todd
 
I’ve sent you a couple of docs that may help - apologies if you 
already have them
 
Cheers
Ben
 

On Sun, 2 Jun 2024 at 16:43, Todd Gibbs via 928uk 
 <mailto:928uk at lists.928.org.uk> <928uk at lists.928.org.uk>
wrote:
 
Gents,
 
Someone put me out of my misery - how do I adjust my 3 speed 
gearbox change up rpm?
 
Currently it changes at 4100rpm.
 
My Bowden cable is not adjustable, it has press fittings both ends.
I’ve adjusted the pressure module and now my gear changes are 
punchier (good), but same 4100rpm. I’ve adjust the bolt thing on 
the side of the gearbox in the mechanism that the Bowden cable pulls on. 4100rpm still.
 
So I’m at a loss. What else is there?
 
Thanks for any help
 
Todd