Marina 4 speed gearbox gearchange extension.

[meverett]

Re: Marina 4 speed gearbox gearchange extension.

To have machined a new longer shaft would still be straight and the selector would still catch on the prop.
This is where I am so far, the 3 blue lines are 1st/3rd, neutral and 2nd/4th and where the u/j will be located on the shaft. I need to keep the original shaft from the gearbox level so I will cut the alu frame at this point and bend up slightly to the selector giving the clearance from the prop.

IMG_4055.JPG

If this doesn't work I will be on the lookout for another rear extension.

[meverett]

Re: Marina 4 speed gearbox gearchange extension.

Thanks Adrian, keep us posted with your development.
Martin.

[b_caswell]

Re: Marina 4 speed gearbox gearchange extension.

A friend of mine ran a rear engine and Hewland box race car and that used what we called a helicopter joint.

When I googled it I came up with this a expensive though

http://www.demon-tweeks.co.uk/motorsport/cv-joints-accessories/racetech-universal-joints

[meverett]

Re: Marina 4 speed gearbox gearchange extension.

Ouch, that is expensive. I have ordered a UJ from Banggood for £9, may take a while to get here though and hopefully will do the job.

[philcoyle]

Re: Marina 4 speed gearbox gearchange extension.

Try Car Builder Solutions, under budget gear change U J https://www.carbuildersolutions.com/...sal-joint-75mm

[stevejgreen]

Re: Marina 4 speed gearbox gearchange extension.

Another possibility. http://uk.rs-online.com/web/p/universal-joints/7906744/

[listerjp2]

Re: Marina 4 speed gearbox gearchange extension.

Would you not need a double universal joint?

Adrian

[listerjp2]

Re: Marina 4 speed gearbox gearchange extension.

Just another thought and it is only a thought.

Keep the original gear selector where it is, take another and u bolt it to a frame.

Then either rubber riv nut or use a number of bobbin type bolts to bolt that frame to the inside of the tunnel, this would hopefully allow some movement in the gearbox.

Then using a double universal coupling to connect an extended shaft, which would also allow more movement of the gearbox.

This would mean you could place the selector anywhere along the tunnel and as high as it could go to miss the drive shaft.

I await a loud bang when this idea is shot down, lol.

Adrian

[meverett]

Re: Marina 4 speed gearbox gearchange extension.

That's not a bad idea but too late for me to try. If I find this doesn't work and have to source another extension I may try that.
My UJ turned up today so may disappear to the garage for an hour or so.

[meverett]

Re: Marina 4 speed gearbox gearchange extension.

Ok, this would work in theory.

IMG_4069.JPG

I have cut the frame and bent it at the same position as where the UJ will be. I have connected the shaft temporarily with some rubber hose. The frame needs reinforcing at this cut and bent point as well.
It selects all gears and clears the propshaft and will bring the gear stick back 7".
Success? No, I don't think it will be strong enough over time as the selector casing does move slightly changing gear.

[h_m_cumming]

Re: Marina 4 speed gearbox gearchange extension.

Yes , but you can strengthen it easily enough. If necessary, do away with the mount to the gear box and mount it with a rubber mount to the top of the tunnel once you have determined the position. The gearbox hardly moves anyway.
Just sent you a message, check your inbox.

[listerjp2]

Re: Marina 4 speed gearbox gearchange extension.

Hi I agree with h_m_cumming.

See my mad idea below.

It will still work with your frame.

Adrian

[stevejgreen]

Re: Marina 4 speed gearbox gearchange extension.

See my mad idea below.

Adrian

Looking for it below, or was it deleted and therefore should be ignored.

Please clarify.

[stevejgreen]

Re: Marina 4 speed gearbox gearchange extension.

Yes , but you can strengthen it easily enough. If necessary, do away with the mount to the gear box and mount it with a rubber mount to the top of the tunnel once you have determined the position. The gearbox hardly moves anyway.
Just sent you a message, check your inbox.

Its an interesting thought but having done some spirited driving with the whole length of the transmission tunnel exposed, except for a panel underneath my left elbow, I was surprised that it was not as rigid as I at first thought, even with good quality engine and gearbox mounts.
I would be cautious following the idea without some form of flexible connection to allow even as little as 5mm.

[Mike]

Re: Marina 4 speed gearbox gearchange extension.

Ok, this would work in theory.

[ATTACH]9106[/ATTACH]

I have cut the frame and bent it at the same position as where the UJ will be. I have connected the shaft temporarily with some rubber hose. The frame needs reinforcing at this cut and bent point as well.
It selects all gears and clears the propshaft and will bring the gear stick back 7".
Success? No, I don't think it will be strong enough over time as the selector casing does move slightly changing gear.

Meverett

I had assumed your gear extension frame was a trial frame as it is made from thin aluminium and pop-rivets - (compare it to the original casting).

However,having proved the principle all that is required now is a sturdier steel version.

Do you have access to a local engineering company?
- if not I could get you a steel one made to your current design for not a great deal of cost - I'd be happy to help if you want to pursue what looks like a very good idea.


You never know there might be a few other interested parties to get several made at the same time?

Regards

Mike