Rover 14 gearbox

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Madnik
Posts: 4
Joined: Sun Dec 08, 2019 4:54 pm

Rover 14 gearbox

Post by Madnik » Mon Oct 07, 2024 10:22 pm

My Rover 14 gearbox 1939, has a crack running down the edge that fits to the bell housing,
Can anyone advise me if a Rover 12 gearbox can be used for a replacement, or are the gear ratio different for a 14?

RobHomewood
Posts: 334
Joined: Tue Oct 22, 2013 8:04 pm

Re: Rover 14 gearbox

Post by RobHomewood » Tue Oct 08, 2024 2:47 pm

Hi Madnik
If your 12 gearbox doesnt work out I have a spare 14/16 gearbox (complete but no clutch) which you might be interested in. Its probably 1947 but identical to the 39 14 as far as I know
Let me know
Rob

Madnik
Posts: 4
Joined: Sun Dec 08, 2019 4:54 pm

Re: Rover 14 gearbox

Post by Madnik » Tue Oct 08, 2024 8:43 pm

Hi RobinHomewood.
Thank you, I will keep this in mind.

TonyG
Posts: 303
Joined: Mon Sep 07, 2015 4:38 pm

Re: Rover 14 gearbox

Post by TonyG » Fri Oct 11, 2024 8:40 am

I’m pretty sure that the gearbox details are included in the Rover Parts Book. I don’t have mine to hand, but I seem to recall the gearbox part numbers are shown as variants against each model so it’s a matter of comparing the numbers on the boxes with the listing. That said, I think Rover used what was available at the time so the listing probably reflects that, rather than what is specifically required. For example, my ‘36 12 Tourer has the same gearbox as a Speed 14. According to the parts book these were fitted for a short period, which included the time my car was made. My guess is they were using up old stock. However, this suggests that a 14 box and 12 box are interchangeable. Whether or not the 14 box is made stronger in some way to manage the extra power of the bigger engine is another question but I doubt you will be testing it to the limits! So if it will physically fit, give it a try. Regarding ratios, this information should also be in the parts book, but I doubt they will be very different and top gear will certainly be the same.

It’s quite a job to get the gearbox out but not particularly complicated. If it’s like my 12s, you will need to remove the front seats, carpets, tunnel cover, pedals and floor plates. Then you have easy access to the prop shaft bolts, Speedo drive, clutch cable, gearbox mounting and remote gear selector. With that lot out of the way, you can undo the bell housing bolts and, with the rear of the engine supported on a jack, withdraw the box and manoeuvre it out of the car.

While the box is out you would be wise to check the rear gearbox mounting. These are rubber and inclined to perish due to the oil that gets on them. Meteor Spares supplied mine. Also, unless known to be ok, it would be worth checking the clutch plate and release bearing. An easy job to change at this point and also available from Meteor (at least they were when I needed some).

Regarding the release bearing, yours will probably be the later type which can be stripped apart and re-packed with grease. You will also have the later type clutch cover, which requires the later bell housing, I believe, so check your replacement gearbox has the same one if you are changing the whole assembly.

One final thing, the release bearing receives lubrication on the input shaft from the engine via some small oil ways. This is detailed, I seem to recall, in the RSR workshop manual where it also advises blocking one of the holes to reduce the possibility of over oiling and contaminating the clutch plate. It’s almost 10 years since I did mine so you need to check exactly what it says.

I hope some of that helps. Sounds like a lot, but very straight forward really!

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

TonyG
Posts: 303
Joined: Mon Sep 07, 2015 4:38 pm

Re: Rover 14 gearbox

Post by TonyG » Sat Oct 12, 2024 2:56 pm

Just had a look at my parts book and an old workshop manual. Suggest you get latest copy of both to help puzzle through any concerns you have.

My parts book only goes up to 1938 because my cars are 36 & 37 models. However, what it does reveal is that the part numbers for the gears are the same for all models, as is the casing and freewheel. This begs the question why it also shows different part numbers for the complete box, except for the Speed 14 of 36 and 12 models of 1937 having the same one, which fits with my own car. The notes relating to this refer to numbers on the gearbox in the form of 701xxx, 711xxx and 721xxx, for 10, 12 and 14 models, the same as used for chassis/engine numbers in 1937. This suggests that your box will be numbered 921xxx, but a later parts book might confirm this. However, this isn’t the gearbox part number in the book!

Looking at my old workshop manual in the technical specs it details that the gear ratios for your 1939 14 are the same as for a 1939 12. Do you know what year your spare 12 box is? Ratios for other years are detailed as well so you can check on this.

All this brings us back to measuring up the 12 box you have for physical size and giving it a go if it’s the same as your 14, which I’d guess it will be. Worth checking on differences though if they are from different years. I doubt you would notice a slight variation in intermediate gear ratios though.

It also says in the workshop manual that post war boxes were redesigned so there are few interchangeable parts with earlier ones. That’s not to say that a later box won’t physically fit in your car though. The later boxes have a greater degree of synchromesh I believe, so might be a worthwhile upgrade if you decide to go that way.

Hope that helps a bit.

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

Madnik
Posts: 4
Joined: Sun Dec 08, 2019 4:54 pm

Re: Rover 14 gearbox

Post by Madnik » Fri Oct 25, 2024 11:55 am

Thanks TonyG.
That’s helps me, I have the parts and workshop manuals, I have been checking part numbers they do differ, When I get around to removing the 14 box I can check against the 12 box.

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