mk3 zephyr 4 overdrive

[Deleted]

Hi all some great reading on the site hope to post a few pics of my zephyr 4 soon she is a 1963 mk3 zephyr 4 bought off ebay rusty in all the usual places so a bit of welding to do Got an overdrive gearbox off ebay not sure if it will work with the 4 pot so any help/ comments would be appreciated with wiring it up or problems i could run in to any way best get out in the garage

[arthur]

Hi welcome to the forum, The 1703cc 4 pot may struggle with overdrive on it's original 3.9:1 ratio diff. Ford fitted the 4.11:1 diff to get the best effects from the overdrive.

[Mick]

Hi and welcome , incidentally the 4.111:1 diff was also fitted as an export option to manual Zephyr 4 cars which may help broaden your search if you intend to find one ........................tho i think you'd be far better selling it to me for 20 quid ;D

Good luck with it and let us know how you get on.

[Deleted]

Thanks Mick 20 quid as much as that wow Going off the idea of trying to fit it now dont really fancy changing the diff aswell think im gunna sit in the garage and have a cry

[Mick]

Was joking about the 20 quid , working overdrives fetch good money which should help put the smile back on your face if you decide to sell it.

[Deleted]

So with the original diff does it mean the car will struggle pulling away or rev its wots its off wen up to speed bit of a numpty with things like this DUH !!!

[Joe]

Hi, I think you will find it strugling to pull away with a six cylinder gearbox as the Z4 has lower gearing in the bottom three gears than a Z6 or Zodiac, top gear will be the same but the Z4 had a higher ratio (lower gear) 3.90-1 diff instead of the 3.54-1 6 fitted to the 6 cylinder cars. I dont think the four cylinder was offered with overdrive as an option. But if you could fit the 4.111 -1 diff it might work.
As Mick says if it works it will fetch a good price so dont dispair!

[michael]

The difference in rolling radius between the original crossplys and radials (particulary lower profiles) would also affect the gearing - typically lowering it by 5 - 10%. Similar in fact to the diff change.

[arthur]

Zephyr 4's were offered withe the overdrive option but it sounds like you have a 6 cylinder version. It all depends if you have everything you need to convert the car not least all the electric wiring, solenoids and overdrive cable and handle. Fitting the complete unit you would compound the gearing problem and so would have to attach the overdrive guts to the 4 cylinder box. The tyre difference as already mentioned would help compensate for the diff issue. It's by no means impossible but it is it worth it. Zephyr 4's with the right ratio tyres have a top speed of 86mph and can cruise quite easily around 60mph. As an aside i have an auto zephyr 4 fitted with the regulation 3.54 diff but it still reduces the top speed to around 78mph. lovely to drive though
Arthur

[Deleted]

Thanks for all your input guys all the solenoids are there no wires though got a mate with the overdrive handle and cable so i think i will give it ago dont need to be wheelspinning away from the lights and as long as i can keep up with traffic to the speed limit that will suite me fine to I will let you all know how i get on and maybe post some pics of the horror story repairs

[Mick]

Cool , good luck with the job .....if you fancy doing a build thread with pics/details of the install it would be much appreciated as i'm sure many including myself would like to fit an overdrive box and it would be a great tech article for the site.

[zephyrmadmick]

hi, just been reading about your o/drive project, i've fitted o/drive to my zephyr 6 & have aquired quite a bit of knowledge on 4/6 o/d g/box,s & will gladly share any info i have aquired, if you need, regards, mick

[Deleted]

Hi mick had a change of plan with the g/box as finances got in the way and sold the o/d box on to Mick (administrator)

[Joe]

I have an overdrive gearbox sitting in my shed at the moment, if anyone's interested in it.

[Ratna Zodiac]

How much Joe?

This has got me thinking...