Vitesse overdrive upgrade

[Paul H]

Hi just purchased a 1969 Vitesse Saloon MK 2 no overdrive

 

One of the known issues is a noisy gearbox -  In general terms is replacing with overdrive worth the extra cost ? 

 

What would be a comfortable cruising speed with a replacement non overdrive gearbox ?

 

What would be a comfortable cruising speed with a replacement  overdrive gearbox ?

 

Thanks in advance for any input 

[TomL]

Hi Bivvyman,

 

A non-overdrive Vitesse on standard rims and 155-tyres does 17.4mph per 1000 revs in top gear.

 

This is very low geared compared to a modern car (my modern car runs at about 35mph per 1000 revs) and it will be far from a relaxed motorway-cruiser.

 

Overdrive will improve things to just shy of 22mph per 1000 revs.

 

Have a look at this website as it explains the effects of diff ration and tyre sizes: http://www.mintylamb.co.uk/gearspeed/

 

Let us know what you decide to do.

 

Tom

[Paul H]

Hi Bivvyman,

 

A non-overdrive Vitesse on standard rims and 155-tyres does 17.4mph per 1000 revs in top gear.

 

This is very low geared compared to a modern car (my modern car runs at about 35mph per 1000 revs) and it will be far from a relaxed motorway-cruiser.

 

Overdrive will improve things to just shy of 22mph per 1000 revs.

 

Have a look at this website as it explains the effects of diff ration and tyre sizes: http://www.mintylamb.co.uk/gearspeed/ 

 

Let us know what you decide to do.

 

Tom

Hi Tom , thanks for reply and beginning to understand the issue - I tried the link and got a Mcaffe Warning not to proceed. Are there any other sites that would help 

Best regards 

[TomL]

Hi,

 

I don't know why that link isn't working.  Try searching: Minty Lamb Ratios

 

It's worth a go.

 

Tom

[Paul H]

Hi,

 

I don't know why that link isn't working.  Try searching: Minty Lamb Ratios

 

It's worth a go.

 

Tom

Hi Tom - All Minty Lamb page have a McAfee warning

 

[Paul H]

Hi Tom - All Minty Lamb page have a McAfee warning

[TomL]

Hi,

I can't explain that I'm afraid.  I have used the site for years - no problem.

 

Tom

[Paul H]

 

Found the page using my iPad , no issues

Many thanks

It's decision time or have I got enough cash . I can change a gearbox though might have to farm out overdrive conversion

[Pete Lewis]

 minty lamb many use it without problems ,  i use Linux and it loads OK

 

apart from the noisy gearbox which  does have  a number of short comings making noise you dont need .

 a cheaper option to raise the diff ratio

from 3.89 :1 to 3.63:1 

 

your existing box can be converted with a new mainshaft   (tkc923) and a number of other parts like mounting and chassis plate ,remote rod cam and inhibitor switch

 

most would use D type overdrive it needs an adadaptor plate to co join the two units 

 

see places like OD spares     http://www.odspares.com/             Overrdrive repairs  http://www.overdrive-repairs.co.uk/      for major units

 

main failings for gearbox noise are 

mainshaft spigot tip worn out

input shaft bearing

layshaft needle roller spindle 

synchro ....broken spings in the sliding hub sleeves

[Clive]

Check out exactly what you do need to convert to OD, it is quite a list if sourcing parts individually. 

You can buy a complete conversion reconditioned, but sit down when you get a price!

 

Used conversions do turn up, but again check what you get and what is needed to complete the conversion.

 

All said and done, I have driven long distances without OD, but at a steady 60mph+ the od is a lovely addition and just feels better. Compare it to driving along the motorway in 4th rather than 5th in a modern car.

 

If you intend mainly shorter drives and quieter/slower roads, I wouldn't worry so much.

[John Bonnett]

You could fit a 3.27 diff which would make a big difference to noise level and the way the car eats up the miles.

[Pete Lewis]

Dont over gear it if you travel a lot 4 up and a boot full of picnic/tools /spares

 

Or you do a lot of hill starts on porlock hill

 

3.27 is GT6 and mainly less loaded than a saloon

 

if you run light then its fine

 

pete

[Paul H]

Check out exactly what you do need to convert to OD, it is quite a list if sourcing parts individually. 

You can buy a complete conversion reconditioned, but sit down when you get a price!

 

Used conversions do turn up, but again check what you get and what is needed to complete the conversion.

 

All said and done, I have driven long distances without OD, but at a steady 60mph+ the od is a lovely addition and just feels better. Compare it to driving along the motorway in 4th rather than 5th in a modern car.

 

If you intend mainly shorter drives and quieter/slower roads, I wouldn't worry so much.

Thanks for input and the driving in 4th on a motorway makes sense so looks like overdrive is the way forward.

[mishmosh]

First mod I make to my cars is overdrive. Wouldn't be without it.

[SpitFire6]

Hi,

 On modern roads, a non-overdrive car is too noisy, drinks fuel and wears the engine out. An OD will pay for itself in x years. X mighty be a big number. LOL.

 

Cheers,

Iain.

[Gully]

Pete's right about avoiding over gearing. When I bought my GT6 it had a 3.27 diff and overdrive - rarely used the overdrive (aside from motorway / dual carriageway blasts) and pulling away uphill took way too much clutch slipping for my liking. Swapped to a 3.63 diff and it's ideal gearing for 'fun' roads and perfectly happy on faster stuff. I think Cookie runs the same combination.

 

Gully

[John Bonnett]

My GT6 ran a 3.27 diff with overdrive and it pulled it easily. A  3.27 diif was a standard fitment on non-overdrive cars so it was designed for it and should be able to cope in all conditions..

[Gully]

I know it was the standard equipment, but for my money 1st gear was too tall - no argument with those who are happy with the compromise on acceleration in favour of non-overdrive cruising. Without OD, my feeling was that the gearbox needed a wider range of gearing. Each to their own.

 

Gully

[SpitFire6]

^Hi,

^{My GT6_Spitfire with OD had a 3.63. diff. The 3.27 is great with an OD. Around 10% difference is not felt.}

 

^{I run a TR saloon transmission and can smoke the 215's if I want with no clutch slip. LOL.}

 

^Cheers,

^Iain.

[Pete Lewis]

Ian yours is a 2500 yes ,,, quite a different torquey machine to a std 2ltr.