1098 4-speed to 5-speed

[warb21]

Just wondering what others would do. I've a v nice 1967 with its original 1098 low mileage engine and 4-speed box, albeit with a 3.9 diff. I want a 5-speed, though, because I do a lot of urban motorway driving on my daily commute. I'm not competent enough to do the work myself. Do I:

A Spend parts and labour on a pricey conversion (and does one always surrender the 4speed as part of the deal?)
B sell my car and look for one with a 5speed (1275cc is ok)
C look out for a car with 5speed in less good condition, buy it, pay to have boxes swapped and sell again at a loss but less than the cost of A
D find someone near me (Manc/North West) who'd enjoy it as a project, and who I'd pay, but less than the cost that the expert garages might charge
E some other solution

I'm not in any hurry. And the 1098 is very sweet as it is so don't really need to change it to 1275.

I've not had my car that long so I don't feel too emotionally connected to that particular one, as long as any other one was the same condition and spec, I'd have just as much fun in it.

Any thoughts?

[bmcecosse]

A standard 1098 engine will struggle badly with a 5 speed box - you will constantly be changing down to 4th. Personally I would do nothing - just run it as is - maybe keep an eye open fora 3.7 final drive at a 'fair' price - but frankly it's not much different to a 3.9 and again a standard 1098 may struggle. You really do need a good 1275 to justify a 5 speed box - and it's not inexpensive !

[simmitc]

I drove a standard 1098 with Ford Type 9 5 speed box for years on dual carriageway trunk roads. Yes, I had to drop from 5th to 5th on any sort of an incline, but other than that it was fine, and quieter than the standard 4-speed. You also gain synchro on 1st which is useful when towing a trailer on a steep hill. Whether it is worth the cost of doing it is a purely personal opinion.

[bmcecosse]

If you do it - you will probably need to change that 3.9 final drive back to the standard 4.22.

[philthehill]

I drove a standard 1098 with Ford Type 9 5 speed box for years on dual carriageway trunk roads. Yes, I had to drop from 5th to 5th on any sort of an incline, but other than that it was fine, and quieter than the standard 4-speed. You also gain synchro on 1st which is useful when towing a trailer on a steep hill. Whether it is worth the cost of doing it is a purely personal opinion.

Must be a very special gearbox having two 5th gears.

[faversham999]

If u buy an car with 5 speed box use the bits , then sell it with your parts on it . You should get more for it standard cars deck more than boy racers

[John Naylor]

Just looking at some numbers:
4.22 to 3.9 diff : 8%
4.22 to 3.7 diff: 14%
Sierra 5 speed 4th to 5th: 22%
But remember changing back to 4th is quicker than changing the axle ratio!

[bmcecosse]

So it's a big overdrive ratio - and may actually be better used with a 4.55 final drive.

[John Naylor]

I reckon 5th would be 13% higher then. Sounds good.

[amgrave]

So fitting a five speed box with 4.55 diff would achieve the same as fitting a 3.7 diff. Fitting the 3.7 diff is a lot easier and cheaper and would make the 4 speed box first gear a bit more useful too.

[bmcecosse]

Exactly....

[John Naylor]

So you think a standard 1098 with a 3.7 diff is a good idea? Amazing!

[amgrave]

Not a standard 1098 no, it would not handle it.

[warb21]

thanks for all the replies. Though I'm confused by the last couple! So I shouldn't just get a 3.7 diff for my standard 1098?

[charlie_morris_minor]

hopefully this might help.. a 3.7 diff does not suit a standard 1098 engine, i have one in my car and the next job on my list is to remove and change back to a 4.2. I do not do that much motorway work and the 3.7 makes driving in town just rubbish as i have to work the engine harder than i would like. A warmed up 1098 with a 3.7 diff i can not comment on, but I think this was Roys set up and he likes \ liked it.

[panky]

I've got a warm 1098 in my Traveller with a 3.7 diff. I ran with the 4.22 for a while and it was very good on acceleration but fitting the 3.7 dulled it back down a bit - but accelerates for longer I do think a standard engine would struggle with one

[John Naylor]

Hence my reason for getting a 5 speed box. In 4th the ratio is 1:1 and it is just as intended with a 1098 and 4.22 axle but you have the option of changing into 5th which is an overdrive and you can reduce the engine revs by about a fifth and may even hear the radio. On some inclines it would be necessary to drop into 4th but that wouldn't worry me unduly. As the whole kit, including box, was £500 I don't think that is very much more expensive than a 3.7 diff from what I've seen advertised. I haven't fitted it yet so I may be disappointed but gaining more torque or changing to 1275 would solve that and make Motorway driving a doddle.

[warb21]

Thanks again - all v helpful.

[The vast minority]

I own the car mentioned above, Roy's traveller. Here's the thing from a guy that has a totally standard 1098 with standard diff in a saloon and a warm 1098 with 3.7 in a traveller.

They have been out together all over the Yorkshire dales

On the flat and on gentle hills the acceleration is about the same, but the standard car can leave the modified one on hills for sure. I can't comment on cruising speed and revs on the motorway or fast A roads from direct experience but it's plainly obvious the traveller would win there so that test wasn't conducted. ill be happy to send details of the spec of this car should you wish to try this route, it's all bolt on and requires neither engine or gearbox removal.


An even better compromise would I think be to fit a 3.7 diff and a 1275 midget engine which strangely enough is exactly my intention this weekend.

Al

[John Naylor]

Roy's 'warming up' sounds v interesting. Can't afford 1275 at the moment so please let us know what has been done!