tell me about overdrives

[petetong]

got this thing in my head, and want to know if you lot think it would work? ;D
my van is fitted with a 4 speed box with column change setup.
now the thing is I really what to keep the column setup, but the gearing is'nt to good for motorway cruising
60 is about 5 1/2 grand on the rev counter..!
I have thought about dropping a different engine and box in it, but it does seem a bit silly to do that when the 3Y lump that's in it is running sweet as..
so.. my idea is to fit an overdrive to it.. then at the flick of a switch would be able to cruse happily all day long!

so the question is what do people know about them,but more to the point know of any that weren't the type that bolted to the back of the box.. (like MG ones seam to be) what I'm thinking is if I could fit it in between the gear box and the rear diff?? make up a short prop the fit between it and the out put on the gear box..

any thoughts idea would be appreciated

[BiAS]

Higher ratio rear diff/axle maybe?

[petetong]

Feb 28, 2010 22:53:53 GMT BiAS said:

Higher ratio rear diff/axle maybe?

i did think of that, but don't want to change the gearing of all 4 gears..

[BiAS]

Hmmm, didn't think of that, is the 'box swappable for a 5 speed out of something else? Does the column shift attach to the box where a traditional stick would've attached on a saloon?
I've personally not encountered an overdrive that isn't bolted to the box.

[B-8-D]

it can be done i have done it at work on a medows engined invictor..
its supprising how much room you will need though.. the overdrive units are rather large and at shortest input flange to output flange will be around 10" long minimum..
and a bigish space you will have to find in the tunnel someplace..
si

[petetong]

that's the thing, trying to find a 5 speed with the column setup is'nt that easy.. it would seem that when Toyota fitted the 5 speed to the hiace, they made them all as stick shifts

the the selector is fitted to the side of the box, not on top like most are!
i have looked at other boxes, 5speed yota ones but all have the selcotor on either the top, or the other side to mine.. and different bell housing set up!
and like you say it would seem that most overdrive units bolt to the rear of the standard box..
but I'm shore couple of years ago, we had a Volvo in work with a set up like i have said.. with a little prop that ran from the rear of the box to the over drive unit..
i might be wrong.. but I'm shore i have seen some thing like it?!!

[petetong]

Feb 28, 2010 23:26:18 GMT B-8-D said:

it can be done I have done it at work on a medows engined invictor..
its supprising how much room you will need though.. the overdrive units are rather large and at shortest input flange to output flange will be around 10" long minimum..
and a bigish space you will have to find in the tunnel someplace..
si

thats sounds interesting.. tell me more..

as for space, thats not a problem.. the gearbox and prop is under the floor on my hiace.. and i bet there's 4ft between the rear of the box and the diff face! about the only thing that's in the way is fresh air ;D

[10mpg]

Didn't the Mitsi L300 vans have a column mounted 5 speeder?

[Team Blitz]

Independent overdrive units are typically very expensive. See the Gearvendors site and become very afraid.

[bortaf]

The 5 speed space cruiser i used to service used cables from the stick maybe possable to mate the 2?

[Deleted]

Some Opel Commodores and Volvo 740`s came with a Laycock overdrive set, just a box on the end of the box, with a switch for shifting. Thats all i can come up with, maybe you can find one of those? Oh, 240`s came with them too, i seem to remember... Shouldnt be that hard to find, bought me a 4+od box for my commo daily for 100 pounds or thereabout

[mdh]

The Suzuki SJ had a seperate 2 speed transfer box - maybe you could gut/modify/bodge the 4wd bit?

[suterman]

The Volvo M46 gearbox is the one you mean Madmaxx.

came on a lot of 240s and 740s. I think the overdrive unit will unbolt from the m46 too IIRC

www.volvo-wiki.com/wiki/Volvo_M46_transmission




If it does unbolt I cant see why you shouldn't be able to make up some brackets and adapt the shafts to fit yours. You'd have to remember to switch off the overdrive in lower gears though, the torque might break it.

May even think about it with our van!


PS, those boxes are ten a penny in volvo circles as most people want M47 speed or even better M90 (ask a UK turbobricker)

[stevea]

Is this the sort of thing you were thinking of?



www.odspares.com/phdi/p1.nsf/supppages/odspares?opendocument&part=4
Lots of info on Laycock overdrives on that site also.

[captainmatt]

Not much info, but the Bachman Turner model works by assuming you ain't seen nothin' yet.

[Rich G]

Mar 1, 2010 13:34:49 GMT captainmatt said:

Not much info, but the Bachman Turner model works by assuming you ain't seen nothin' yet.

True but once seen though; here's something that you're never gonna forget...

[petetong]

thanks all for the replys..
and i think it was a volvo 740 that i had seen one fitted to..
think that might be an easy find.. if i look hard enough

suzuki sj box is a 2 speed on, but its a hi-low box.. so hi range is just 1 to 1.. so out put wouldn't be any different.. and the low speed is just that lower than input. 4.5 on a 410 if i remeber right..
so it would lower the over all gearing..not really any good to me

Mar 1, 2010 11:26:52 GMT stevea said:

Is this the sort of thing you were thinking of?



www.odspares.com/phdi/p1.nsf/supppages/odspares?opendocument&part=4
Lots of info on Laycock overdrives on that site also.

now that would do the job..!! but i don't no whether i should look to see how much one would be!
but going back to the volvo unit.. think i might see if i could find one of them,or one that's fitted to a MGB.. see if it could be unbolted and a blanking plate made up to cap the end off..and see if a drive flange could be machined up to fit the input shaft..
sound feasible??

[popuptoaster]

Mar 1, 2010 21:16:53 GMT petetong said:

suzuki sj box is a 2 speed on, but its a hi-low box.. so hi range is just 1 to 1.. so out put wouldn't be any different.. and the low speed is just that lower than input. 4.5 on a 410 if I remeber right..
so it would lower the over all gearing..not really any good to me

fit it backwards

[petetong]

Mar 1, 2010 22:28:41 GMT popuptoaster said:

Mar 1, 2010 21:16:53 GMT petetong said:

suzuki sj box is a 2 speed on, but its a hi-low box.. so hi range is just 1 to 1.. so out put wouldn't be any different.. and the low speed is just that lower than input. 4.5 on a 410 if I remeber right..
so it would lower the over all gearing..not really any good to me

fit it backwards

yeap.. that would work.. but(and there is allwas a but!)don't think it would like running backwards!
I have had lots to do with the sj transfer box..(had loads of sj over the years.. and even built my own crawler gear t- box.. a rocklobster!) there a good little box. but not the strongest!
not only that but would have to do some really fancy fabrication to get the lever to work from haft way down the van,to up in the cab!!
and thay won't change from hi to low ratios at high RPM
it would defo spit its guts out if you tried that
but its still a bloody good idea

[popuptoaster]

most vans are geared low so they can still do hill starts when fully loaded, if your running light or empty most of the time and it will pull away in second with no bother i'd try gearing it up a bit with a higher ratio diff or axle, especially if your now running low profile tyres on it, i suspect my van will need gearing up when its done but I'm gonna get it running and see what its like first.