can you get a "taller" 4th gear ?

[rob]

rather than replace the gearbox to get a better top end speed is it possible to strip gearbox and fit a different 4th gear ?
its a standard 1600 ce box

 

[mjknight71]

2lt g/b from a l8 type4 is apparently better...

 

[slammedresto]

this is a hot topic of late

ive gone late bay 6 rib box, has a taller 4th :wink:

 

[the councillor]

there's (understandably) a lot of misconceptions and misunderstandings about gearboxes.

the 2 litre box has a shorter 4th gear than the 1600.

but to get the final drive ratio you have to multiply the gear ratio and the ring & pinion together, so for motorway cruising you need the tallest 4th gear and the tallest R&P, and it just so happens (well, you know what i mean, it wasn't a random choice or anything) that the R&P in the 2 litre box is significantly taller than the 1600 R&P, so multiplied together you get a better overall final drive ratio (for cruising (or higher top speed)) from the 2 litre than you do from the 1600.

oddly enough, the 1800 'box has the same 4th as the 2 litre, but a shorter R&P, although it's still taller than the 1600's, so if you were to rebuild (or have rebuilt) an 1800 'box with the 4th gears from a 1600 'box, you'd get an even better final drive than the 2 litre.

how exciting

hope this helps somebody because i've got a headache now :roll:

 

[rob]

hope this helps somebody because i've got a headache now :roll:

yes it does help thanks

 

[rob]

this is a hot topic of late

ive gone late bay 6 rib box, has a taller 4th :wink:

i agree this would be the easiest option ..... just a bit curious as to other options due to these boxs commanding such a good price

 

[aggri1]

G'day!

there's (understandably) a lot of misconceptions and misunderstandings about gearboxes.
...
if you were to rebuild (or have rebuilt) an 1800 'box with the 4th gears from a 1600 'box, you'd get an even better final drive than the 2 litre.

'Better' is probably a judgement relative to your driving style. For me, I feel that the standard gearbox is the 'best' in all three of my busses ('67, '69 and '74). I don't feel the need to go really fast, and prefer not to be slowed down drastically and have to gear down at every slight hill because of the too-tall fourth gear. I have standard motors in the Bays. But, if you do drive fast and have a big donk to push you along, yeah, then it would make sense to have the taller gears.

Also if you just change fourth, you might end up with a too-large step from third to fourth. This might be rather annoying in some situations.

I noticed a significant difference in effective gearing just by getting some proper tyres. Changing the P185/65-15s (on Mangel rims) for 185R15 tyres (on stock rims) dropped the revs a fair bit it felt like; I noticed the decreased acceleration too, and my speedo was suddenly correct again. That's also a very easy change to make. (This was on the Splitty).

Cheers, A.

 

[the councillor]

G'day!
'Better' is probably a judgement relative to your driving style.

g'day !

there's literally hundreds of variables, agreed, but if you look at the original post...

rather than replace the gearbox to get a better top end speed is it possible to strip gearbox and fit a different 4th gear ?

then the only possible way to get a better top speed is to alter the final drive ratio, hence the nature of my reply.

 

[aggri1]

...then the only possible way to get a better top speed is to alter the final drive ratio, hence the nature of my reply.

Yep, you're absolutely right! (It is still only early here, I'm eating breakfast right now).

Cheers, A.

 

[the councillor]

well, your reply was bang on to be honest... yes changing the final drive ratio in fourth offers you a better cruising ability / potentially higher top speed, but as you hint at, it's not always as simple as that 8)

(dark here; sleet :x )

 

[fredster]

then the only possible way to get a better top speed is to alter the final drive ratio

Not true. What about putting larger tyres on?

 

[the councillor]

jesus wept will you people please stop quoting me out of context :lol:

read what i've typed again, slowly this time, and try and concentrate :wink:

the original post asks if it's possible to get a better top speed by replacing the 4th gear in a geabox, yeah ? no mention of tyres.

i reply that yes, it is possible, and list the various ways to get a 'better' top speed capability.

then aggri comes along then says it's not necessarily 'better' it just depends on your driving style, to which i reply that of course it does, but the original question asked only about a higher top speed WITH RELATION TO GEARBOX MODIFICATIONS, regardless of driving style.

now you come along and ask about tyres ????

well of course you'll get a higher top speed if you put taller tyres on, that's a given, but where in the original post does he mention tyres ? taking pedantry to a new level a higher top speed might be attained by the addition of booster rockets, but you have to draw the line somewhere.

to get a better top end speed is it possible to strip gearbox and fit a different 4th gear ?

YES. the end.

*elvis has left the building*

8)

 

[Araon]

but surely top end speed could be improved by cutting out all the metal and manufacturing an entirely fiberglass body shell, filling your tyres with helium and forcing your passengers onto a Belsen style diet regime.

 

[sparkywig]

If you want to go faster, buy something that's not box-shaped........................ :roll:

 

[justin pane]

Yes you can the CE box 4th is .82. I understand Longenterprises do a .77, give BEARS a ring they will help.

 

[the councillor]

but surely top end speed could be improved by cutting out all the metal and manufacturing an entirely fiberglass body shell, filling your tyres with helium and forcing your passengers onto a Belsen style diet regime.

quality

offends my liberal sensibilities

overall ----> :lol:

 

[aggri1]

I don't want Elvis to leave just yet, even if jesus weeps. :wink:

Would it perhaps be a nicer drive if one were to change the ring and pinion rather than the 4th gear? That would avoid having a very large jump from 3rd to 4th gear by keeping the ratios the same but scaling them all up a bit. (EDIT: not sctrictly 'up', but 'faster').

(I just couldn't resist!)

Cheers, A.

 

[the councillor]

i like the cut of your jib :twisted:

fancy meeting up for a beer :wink: