Increase in road speed by swapping gearbox

[parker999]

Hi all !!!
Can Anyone confirm that if I change my ce code gearbox for one from a 1975 bay- 1700-2.0 gearbox, will I get a better cruising speed of say 70mph and keep my 1600tp engine.,.
Currently manage 50 - 55 mph with current box.,

 

[Robert Parry]

Yes it will give you a higher cruising speed. As long as you have the engine to do it. I have never tried it with the stock 1.6 Robert. My first post, not so difficult! :shock:

 

[john the horse]

true but can badly affect your cooling as you have slightly less rpm and if ya running a stock engine can be working harder too. having said that i know a guy with this set up and has had no trouble although he dont live in a hilly area.

jth
'

 

[Tofufi]

As above, you'll have lower revs at speed.

However, this comes at the expense of having to work the engine harder in each gear 1-3, with larger gaps between (at least some of) the gears. I found my 1600 with standard 'box going over the Pyrenees felt like it needed more gears going up the steep hills. I'd imagine with the longer 4th you may well need to drop down to 3rd on some steep motorway hills.

I've just fitted a 5 speed 'box to my bus, which gives higher 1st, 2nd and 3rd gears. 4th stays approx the same, and you get a 5th gear a fair bit higher than the 1600 4th gear. It's far nicer to drive, as the gears are closer together meaning you don't need to rev so high before changing gear.

More details here:
http://forum.earlybay.com/viewtopic.php?f=4&t=60286" onclick="window.open(this.href);return false;

 

[hart5lizard]

I may be sounding dumb, but you say, you need the low gearing of the 3 rib box to allow the fan on the engine to rotate at the most efficient speed for optimum cooling.

What about a 1303s beetle, does that not have the exact same engine as a 1600 bay?, coupled to an at code box with higher gearing, would reduce the speed of the cooling fan.

regards Dan

 

[Resto-raider]

A beetle only weighs half to a third of what a (Westy) van weighs.
Van engines need to work much harder and thus heat up much quicker.

 

[hart5lizard]

So if you added a larger crank pulley, the cooling fan would spin quicker, would that increase the cooling effect at lower revs ?

 

[68_early_bay]

So if you added a larger crank pulley, the cooling fan would spin quicker, would that increase the cooling effect at lower revs ?

But at higher revs you could then have the possibility of spinning the fan too fast and it could disintegrate :lol:

 

[*Sam*]

Interestingly if you read Richard atwell's web site he disagrees with the theory of long gears equal less cooling ( when referring to a 6rib box or 1303s box)
http://www.ratwell.com" onclick="window.open(this.href);return false;

 

[parker999]

Thanks everyone for your replies

 

[Trikky2]

Yes putting a 2 litre gearbox on your 1600 will significantly lower the engine rpm at any given road speed.

Cooling only becomes an issue if the engine is laboured at too low an rpm - but this applies to any engine and gearbox combination.

The problem with doing this conversion is that the 1600 does not develop sufficient power for the longer ratios of a 2 litre gearbox.

This means that on a flat road with no headwind your bus will have a nice overdrive type top gear. The problem comes when you have headwinds or anything more than a slight incline. You will need to change down to third rather often.

A stock 1600 produces around 58 bhp if its in good condition. You need around 75 to 80 to run a 2 litre gearbox comfortably IMO.

Wheel and tyre combinations can significantly affect overall gearing, so if using or considering non stock wheels/tyres its worth checking on one of those wheel and tyre calculators online.

 

[EgoTrippin]

My bus struggled on anything other than the flat with the 1600sp and 1302 box. Even overheated in Holland on the flat with a headwind!

You should really run a bigger motor, say 1776 to really get the best use from a longer ratio box. Or get decent sized rear tyres.

Now running a 2007 stroker motor with a re-built 1302 box and rear tyres which match the stock radius. Result is 105mph at 5000rpm on the rolling road. I don't mind dropping down to 3rd on hills as it easily does 60mph in 3rd
When its on cam it will overtake normal traffic going uphill at 70 ish mph

 

[Tofufi]

Interestingly if you read Richard atwell's web site he disagrees with the theory of long gears equal less cooling ( when referring to a 6rib box or 1303s box)
http://www.ratwell.com" onclick="window.open(this.href);return false;

Please could you give us a clue which article that can be found in? 8)

I've not found my van runs any hotter with the 5 speed (which has similar 5th gear to a 6-rib 4th), although I'm careful to not go into 5th until I'm at 40mph or above...

The problem with doing this conversion is that the 1600 does not develop sufficient power for the longer ratios of a 2 litre gearbox.

This means that on a flat road with no headwind your bus will have a nice overdrive type top gear. The problem comes when you have headwinds or anything more than a slight incline. You will need to change down to third rather often.

I've got to agree with this :lol:

I've got a tintop microbus, so it's often lightly loaded. I'd bet a fully laden camper with a stock 1600/6 rib gearbox would be frustrating on hills.

 

[*Sam*]

I will see if I can find it again, I stumbled across it last week whilst trying find out how long a standard box is.
I run a 1303s box in my bus with my standard 1600 SP but I generally drive at 55-60mph so not really stressing the engine.
I only have to change down on very steep hills such as the ones found on the A30 Cornwall.
I am however at present running 186/65/15 tyres which are under sized.
I will be replacing them with 195/70/15 which I believe are more like a standard bus size

 

[*Sam*]

http://www.ratwell.com/technical/FAQ.html" onclick="window.open(this.href);return false;

This is the link 4.8 is the parogrsph to read, basically what you have said about not changing up gear to early is what keeps your engine temp down is spot on.

 

[Tofufi]

http://www.ratwell.com/technical/FAQ.html

This is the link 4.8 is the parogrsph to read, basically what you have said about not changing up gear to early is what keeps your engine temp down is spot on.

Thanks. Can't argue with that.

My engine 'seems' to run slightly cooler with the 5 speed, but that's only based on holding the dipstick after a run

Our buses do have quite a large frontal area to push through the air