3.8 Auto to Manual Advice

[malky1965]

Hi, I have a 1961 3.8 Auto which has been stripped to a bare shell for full restoration, I was originally going to keep it as an Auto for originality but have since been wondering whether to convert it to a manual. If I did what is the best option? 4 speed full synchro moss with OD or 5 speed getrag.

What is meant by long tail or short tail? How do I know what would be in mine if it were a manual?

Has anyone done this conversion and what parts do I need to accumulate, any advice and or help would be appreciated.

Regards
Malcolm

[Tilleyjon]

If you want more originality go moss, else go Getrag.

Getrag setup will set you back up to £5K including propshaft, bellhousing clutch adaptor plate etc.

Moss box you could pick up for under £1K, easy change, but you will need overdrive wiring, new steering cowl pedals etc.

There is a bit to consider, once you have decided, it is simpler to advise way forward.

[malky1965]

Hi, Thanks for your reply, The car will only be used for Sunday drives and car shows etc and possibly Le Mans classic every couple of years but never intended to be a race car getting hammered everywhere. If I were to go Moss do you know which box and OD I should be looking for as I don't know anything about the different versions, obviously I would want full synchro but i have read somewhere that this box was used in Morgans etc and make sure I don't get one with certain prefixes or letters at the end but I can't remember where I read it. If someone could tell me what part numbers I need to look out for in the box and OD unit for a 3.8 Mk2 it would help me a lot and as I said previously, what is Long tail short tail?

Regards
Malcolm

[PPV]

Not done this myself but seem to recall a technical article on the subject in the magazine. Have you tried using the search facility on the forums or magazine files? You could ring Ken Jenkins who I am sure will advise accordingly.
Regards,

[Tilleyjon]

Couple of links to pedal boxes on ebay

http://www.ebay.co.uk/itm/jaguar-420-s- ... Sw241Ye8j9
http://www.ebay.co.uk/itm/Jaguar-Mk2-ma ... SwHMJYLu2k

They are the same pedal box, brake master cylinder can be swapped from your car, you will need clutch servo.

I am quickly checking in will post more info later

[Martec]

Just to add a little extra information, Jaguar used two manual gearboxes in the MkII,

The early and noisy 'Moss' box which only has synchromesh on 2nd 3rd and 4th gear. You will be lucky to find a moss box in good nick as the synchro rings are part of the gear so can't be reconditioned. I'm sure people will say they have a wonderful box, but my original moss box was worn and a dog.

I replaced this with the slightly later full synchro box and overdrive, this has separate brass/bronze synchro rings so can be reconditioned (as was mine). Some say it is agricultural (not me), but I like it as it suits the car and I can get really nice smooth gear changes. I fitted this box because it was far cheaper than the none original boxes and fitted straight in with a suitable propshaft.

No idea what short or long tail means, as you have an auto then the tunnel is wide so no problem in fitting the manual box. You will need a different flywheel I expect and a clutch cylinder and peddle to suit.

Someone has already recommended you talk to Ken Jenkins.

Best wishes
Brian

[oldtimer]

Just read Martec's thread above-- I suggest re - read and remember. Absolutely dead accurate.
There are / were two types of overdrive unit. the later version was referred to as the compact overdrive.
I do believe the overall length of the two remain the same when measured from the bell housing face to the overdrive out put flange face.
The Auto does not have a flywheel it has a flex plate - so a flywheel with starter ring will be required along with a clutch centre plate and cover plate, cluch master cylinder and associated bits and pieces.
I would suggest you try and find a dead S type - every thing you need. Just by- the - way this gear box has a 5psi oil pressure fed system, excellent box.

Not a bad job you are considering but does need some careful study of the detail. Best of luck and keep us up to date

For what it is worth, in my opinion the manual version is a vast improvement

Oldtimer

[malky1965]

Thanks for all the replies, a lot of good information here. The Jaguar spares day is coming up and just needed a shopping list of parts I would require.
How would I know if it was a full synchro box, what do I look for, part numbers etc. I did think manual would be a better option than the auto although a fair bit of work involved, however it is down to a bare shell at the moment so no better time to do it I suppose.

Regards
Malcolm

[Tilleyjon]

The Prefix for the full synchro box is JCN, the N is the overdrive. This later box was actually built by Jaguar based on the Moss I think with Moss parts, but I am not positive on that.

The tail length refers to the gear lever position, it is a longtail on the MK2.

Take a look at this ad if you scroll down, they say they have an all synchro box for sale, but its showing as pending on their website.

http://www.ebay.co.uk/itm/Jaguar-MkII-M ... SwPhdU16gg

[malky1965]

The Prefix for the full synchro box is JCN, the N is the overdrive. This later box was actually built by Jaguar based on the Moss I think with Moss parts, but I am not positive on that.

The tail length refers to the gear lever position, it is a longtail on the MK2.

Take a look at this ad if you scroll down, they say they have an all synchro box for sale, but its showing as pending on their website.

http://www.ebay.co.uk/itm/Jaguar-MkII-M ... SwPhdU16gg

I did mail this company yesterday and they say they have one available with OD for £1000 with no bell housing and not refurbished,

Is this price about the norm?

Thanks

[Martec]

Talk to Ken Jenkins

[ChrisDixon]

I don't know if this applies to MK2s but on the S Type the auto transmission tunnel is wider than the manual which means that you can remove the gearbox without disturbing the engine. One thing you will need if fitting a Jag box is a manual gearbox crossmember. If you are looking for a box from a S-type wasn't there one in the JEC classifieds? If not, message me as someone I bought some other bits from did have one last time i spoke to them.

Oh and did anyone mention axle ratios? Again I'm quoting S Type for which the automatic and non-overdrive models had 3.54:1 and overdrive cars 3.77:1 so if you go for an overdrive gearbox you'll end up with taller gearing in overdrive top.

[oldtimer]

Having the higher 3.77 axle will be no bad thing for Motor way driving. I put a 4.2 engine in my S type and the combination worked well. I did a daily commute in it for years.

[Martec]

As my Moss box didn't have overdrive I also have the higher ratio back axle, better for economy and no real loss of acceleration.
Brian

[ChrisDixon]

Having the higher 3.77 axle will be no bad thing for Motor way driving. I put a 4.2 engine in my S type and the combination worked well. I did a daily commute in it for years.

Mine has an E-Type diff which is even taller than the 3.54 I believe its a 3.07 which gives 33 MPH per 1000 RPM which means relaxed motorway crusing but not much go in 2nd!